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Papers on GHG emissions from bioenergy related land-use

Posted by Ari Jokimäki on March 10, 2014

This is a list of papers on GHG emissions from bioenergy related land-use. The list is not complete, and will most likely be updated in future in order to make it more thorough and more representative.

Damaged forests provide an opportunity to mitigate climate change – Lamers et al. (2014) “British Columbia (BC) forests are estimated to have become a net carbon source in recent years due to tree death and decay caused primarily by mountain pine beetle (MPB) and related post-harvest slash burning practices. BC forest biomass has also become a major source of wood pellets, exported primarily for bioenergy to Europe, although the sustainability and net carbon emissions of forest bioenergy in general are the subject of current debate. We simulated the temporal carbon balance of BC wood pellets against different reference scenarios for forests affected by MPB in the interior BC timber harvesting area using the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3). We evaluated the carbon dynamics for different insect-mortality levels, at the stand- and landscape level, taking into account carbon storage in the ecosystem, wood products and fossil fuel displacement. Our results indicate that current harvesting practices, in which slash is burnt and only sawdust used for pellet production, require between 20–25 years for beetle-impacted pine and 37–39 years for spruce-dominated systems to reach pre-harvest carbon levels (i.e. break-even) at the stand-level. Using pellets made from logging slash to replace coal creates immediate net carbon benefits to the atmosphere of 17–21 tonnes C ha−1, shortening these break-even times by 9–20 years and resulting in an instant carbon break-even level on stands most severely impacted by the beetle. Harvesting pine dominated sites for timber while using slash for bioenergy was also found to be more carbon beneficial than a protection reference scenario on both stand- and landscape level. However, harvesting stands exclusively for bioenergy resulted in a net carbon source unless the system contained a high proportion of dead trees (>85%). Systems with higher proportions of living trees provide a greater climate change mitigation if used for long lived wood products.” Lamers, P., Junginger, M., Dymond, C. C. and Faaij, A. (2014), Damaged forests provide an opportunity to mitigate climate change. GCB Bioenergy, 6: 44–60. doi: 10.1111/gcbb.12055. [Full text]

Sequester or substitute—Consequences of increased production of wood based energy on the carbon balance in Finland – Kallio et al. (2013) “Forests play an important role in mitigating climate change. Forests can sequester carbon from the atmosphere and provide biomass, which can be used to substitute for fossil fuels or energy-intensive materials. International climate policies favor the use of wood to substitute for fossil fuels rather than using forests as carbon sink. We examine the trade off between sequestering carbon in forests and substituting wood for fossil fuels in Finland. For Finland to meet its EU targets for the use of renewable energy by 2020, a considerable increase in the use of wood for energy is necessary. We compare scenarios in which the wood energy targets are fully or partially met to a reference case where policies favoring wood based energy production are removed. Three models are used to project fossil fuel substitution and changes in forest carbon sinks in the scenarios through 2035. Finnish forests are a growing carbon sink in all scenarios. However, net greenhouse gas (GHG) emissions will be higher in the medium term if Finland achieves its current wood energy targets than if the use of energy wood stagnates or decreases. The volume of GHG emissions avoided by replacing coal, peat and fossil diesel with wood is outweighed by the loss in carbon sequestered in forests due to increased biomass removals. Therefore, the current wood energy targets seem excessive and harmful to the climate. In particular, biodiesel production has a significant, negative impact on net emissions in the period considered. However, we did not consider risks such as forest fires, wind damage and diseases, which might weaken the sequestration policy. The potential albedo impacts of harvesting the forests were not considered either.” A.M.I. Kallio, O. Salminen, R. Sievänen, Journal of Forest Economics, Volume 19, Issue 4, December 2013, Pages 402–415, http://dx.doi.org/10.1016/j.jfe.2013.05.001.

Effects of stump extraction on the carbon sequestration in Norway spruce forest ecosystems under varying thinning regimes with implications for fossil fuel substitution – Alam et al. (2013) “The overall aim of this work was to assess the effects of stump and root extraction on the long-term carbon sequestration and average carbon storage in the integrated production of energy biomass and stemwood (pulpwood and sawlogs) under different thinning options (unthinned, current thinning and 30% increased thinning thresholds from current thresholds). The growth and development of Norway spruce (Picea abies L. Karst.) stands on a fertile site (Oxalis-myrtillus) in central Finland (Joensuu region: 62˚39΄N, 29˚37΄E) was simulated for two consecutive rotation periods (80 + 80 years/160 years). Stemwood and energy biomass production, carbon sequestration, and average storage and emission dynamics related to the entire production process of biomass were assessed. The assessment was done by employing a life cycle assessment tool, which combines simulation outputs from an ecosystem model and the related technosystem emissions. It was found that stump and root harvesting constituted 21–36% of the total biomass production (energy biomass and stemwood) depending on the thinning regimes and rotation period. No considerable effect was found in stemwood production when stump and root extraction was compared to the regime in which stumps and roots were left at the site. Stump and root extraction did not affect carbon sequestration on the following rotation and, in fact, an increase in forest growth was found for the unthinned and 30% increased thresholds compared to the first rotation. The results also showed that if current thinning threshold is increased, win-win situations are possible, especially when climate change mitigation is the main concern. The substitution of coal with energy biomass is possible without reducing carbon storage in the forest ecosystem. The utilization of energy biomass, including stumps and roots, instead of coal could reduce up to 33% of emissions over two rotation periods depending on the thinning regimes. Even if stumps and roots were excluded, a maximum of 19% carbon emissions could be reduced by using only logging residues.” Alam, A., Kellomäki, S., Kilpeläinen, A. and Strandman, H. (2013), Effects of stump extraction on the carbon sequestration in Norway spruce forest ecosystems under varying thinning regimes with implications for fossil fuel substitution. GCB Bioenergy, 5: 445–458. doi: 10.1111/gcbb.12010.

The ‘debt’ is in the detail: A synthesis of recent temporal forest carbon analyses on woody biomass for energy – Lamers & Junginger (2013) “The temporal imbalance between the release and sequestration of forest carbon has raised a fundamental concern about the climate mitigation potential of forest biomass for energy. The potential carbon debt caused by harvest and the resulting time spans needed to reach pre-harvest carbon levels (payback) or those of a reference case (parity) have become important parameters for climate and bioenergy policy developments. The present range of analyses however varies in assumptions, regional scopes, and conclusions. Comparing these modeling efforts, we reveal that they apply different principle modeling frameworks while results are largely affected by the same parameters. The size of the carbon debt is mostly determined by the type and amount of biomass harvested and whether land-use change emissions need to be accounted for. Payback times are mainly determined by plant growth rates, i.e. the forest biome, tree species, site productivity and management. Parity times are primarily influenced by the choice and construction of the reference scenario and fossil carbon displacement efficiencies. Using small residual biomass (harvesting/processing), deadwood from highly insect-infected sites, or new plantations on highly productive or marginal land offers (almost) immediate net carbon benefits. Their eventual climate mitigation potential however is determined by the effectiveness of the fossil fuel displacement. We deem it therefore unsuitable to define political guidance by feedstock alone. Current global wood pellet production is predominantly residue based. Production increases based on low-grade stemwood are expected in regions with a downturn in the local wood product sector, highlighting the importance of accounting for regional forest carbon trends.” Lamers, P. and Junginger, M. (2013), The ‘debt’ is in the detail: A synthesis of recent temporal forest carbon analyses on woody biomass for energy. Biofuels, Bioprod. Bioref., 7: 373–385. doi: 10.1002/bbb.1407.

Carbon dioxide emissions from wood fuels in Sweden 1980–2100 – Wibe (2012) “It is often assumed that wood fuels are carbon neutral. This is approximately true in the very long run since the emissions from burning wood fuels are compensated by the uptake from new trees. But it is not true in the short- and the medium term due to a number of factors. This problem is analyzed in detail in this paper, where the net carbon (dioxide) effect of using wood residues in Sweden 1980–2100 is calculated. Two important implications of the program for using wood fuels are considered: (i) the decrease of carbon stored in logging residues due to a faster transformation to carbon dioxide and (ii) delayed growth of new forest generations when logging residues are removed from the forest and used as fuel. The effects of both these factors are calculated (and projected) for the period 1980–2100. The main result is that wood fuels (in the form of wood residues) emits about 60% of the carbon dioxide that would have been emitted if the corresponding amount of energy would, have been produced by oil. One policy implication of this is that emissions from wood fuels should not, as is now the practice, be ignored and by definition equaled to zero, in national and international statistics of green house gas emissions.” Sören Wibe, Journal of Forest Economics, Volume 18, Issue 2, April 2012, Pages 123–130, http://dx.doi.org/10.1016/j.jfe.2011.11.003.

Net atmospheric impacts of forest bioenergy production and utilization in Finnish boreal conditions – Kilpeläinen et al. (2012) “The net CO2 exchange of forests was investigated to study net atmospheric impact of forest bioenergy production (BP) and utilization in Finnish boreal conditions. Net CO2 exchange was simulated with a life cycle assessment tool over a 90-year period and over the whole Finland based on National Forest Inventory data. The difference in the net exchanges between the traditional timber production (TP) and BP regime was considered the net atmospheric impact of forest bioenergy utilization. According to the results, forests became net sources of CO2 after about 20 years of simulation, and the net exchange was higher in the BP regime than in the TP regime until the middle of the simulation period. From 2040 onwards, the net exchange started to decrease in both regimes and became higher in the TP regime, excluding the last decade of the simulation. The shift of forests to becoming a CO2 source reflected the decrease in CO2 sequestration due to the increasing share of recently harvested and seedling stands that are acting as sources of CO2, and an increase of emissions from degradation of wood products. When expressed in terms of radiative forcing, the net atmospheric impact was on average 19% less for bioenergy compared with that for coal energy over the whole simulation period. The results show the importance of time dependence when considering dynamic forest ecosystems in BP and climate change mitigation. Furthermore, the results emphasize the dualistic role and possibilities of forest management in controlling the build and release of carbon into and from the stocks and in controlling the rate of the build speed, i.e. growth. This information is needed in identifying the capability and possibilities of ecosystems to produce biomass for energy, alongside other products and ecosystem services (e.g. pulp wood and timber), and simultaneously to mitigate climate change.” Kilpeläinen, A., Kellomäki, S. and Strandman, H. (2012), Net atmospheric impacts of forest bioenergy production and utilization in Finnish boreal conditions. GCB Bioenergy, 4: 811–817. doi: 10.1111/j.1757-1707.2012.01161.x.

Is woody bioenergy carbon neutral? A comparative assessment of emissions from consumption of woody bioenergy and fossil fuel – Zanchi et al. (2012) “Under the current accounting systems, emissions produced when biomass is burnt for energy are accounted as zero, resulting in what is referred to as the ‘carbon neutrality’ assumption. However, if current harvest levels are increased to produce more bioenergy, carbon that would have been stored in the biosphere might be instead released in the atmosphere. This study utilizes a comparative approach that considers emissions under alternative energy supply options. This approach shows that the emission benefits of bioenergy compared to use of fossil fuel are time-dependent. It emerges that the assumption that bioenergy always results in zero greenhouse gas (GHG) emissions compared to use of fossil fuels can be misleading, particularly in the context of short-to-medium term goals. While it is clear that all sources of woody bioenergy from sustainably managed forests will produce emission reductions in the long term, different woody biomass sources have various impacts in the short-medium term. The study shows that the use of forest residues that are easily decomposable can produce GHG benefits compared to use of fossil fuels from the beginning of their use and that biomass from dedicated plantations established on marginal land can be carbon neutral from the beginning of its use. However, the risk of short-to-medium term negative impacts is high when additional fellings are extracted to produce bioenergy and the proportion of felled biomass used for bioenergy is low, or when land with high C stocks is converted to low productivity bioenergy plantations. The method used in the study provides an instrument to identify the time-dependent pattern of emission reductions for alternative bioenergy sources. In this way, decision makers can evaluate which bioenergy options are most beneficial for meeting short-term GHG emission reduction goals and which ones are more appropriate for medium to longer term objectives.” Zanchi, G., Pena, N. and Bird, N. (2012), Is woody bioenergy carbon neutral? A comparative assessment of emissions from consumption of woody bioenergy and fossil fuel. GCB Bioenergy, 4: 761–772. doi: 10.1111/j.1757-1707.2011.01149.x.

Harvesting in boreal forests and the biofuel carbon debt – Holtsmark (2012) “Owing to the extensive critique of food-crop-based biofuels, attention has turned toward second-generation wood-based biofuels. A question is therefore whether timber taken from the vast boreal forests on an increasing scale should serve as a source of wood-based biofuels and whether this will be effective climate policy. In a typical boreal forest, it takes 70–120 years before a stand of trees is mature. When this time lag and the dynamics of boreal forests more generally are taken into account, it follows that a high level of harvest means that the carbon stock in the forest stabilizes at a lower level. Therefore, wood harvesting is not a carbon-neutral activity. Through model simulations, it is estimated that an increased harvest of a boreal forest will create a biofuel carbon debt that takes 190–340 years to repay. The length of the payback time is sensitive to the type of fossil fuels that wood energy replaces.” Bjart Holtsmark, Climatic Change, May 2012, Volume 112, Issue 2, pp 415-428, DOI: 10.1007/s10584-011-0222-6. [Full text]

Land-use change to bioenergy production in Europe: implications for the greenhouse gas balance and soil carbon – Don et al. (2012) “Bioenergy from crops is expected to make a considerable contribution to climate change mitigation. However, bioenergy is not necessarily carbon neutral because emissions of CO2, N2O and CH4 during crop production may reduce or completely counterbalance CO2 savings of the substituted fossil fuels. These greenhouse gases (GHGs) need to be included into the carbon footprint calculation of different bioenergy crops under a range of soil conditions and management practices. This review compiles existing knowledge on agronomic and environmental constraints and GHG balances of the major European bioenergy crops, although it focuses on dedicated perennial crops such as Miscanthus and short rotation coppice species. Such second-generation crops account for only 3% of the current European bioenergy production, but field data suggest they emit 40% to >99% less N2O than conventional annual crops. This is a result of lower fertilizer requirements as well as a higher N-use efficiency, due to effective N-recycling. Perennial energy crops have the potential to sequester additional carbon in soil biomass if established on former cropland (0.44 Mg soil C ha−1 yr−1 for poplar and willow and 0.66 Mg soil C ha−1 yr−1 for Miscanthus). However, there was no positive or even negative effects on the C balance if energy crops are established on former grassland. Increased bioenergy production may also result in direct and indirect land-use changes with potential high C losses when native vegetation is converted to annual crops. Although dedicated perennial energy crops have a high potential to improve the GHG balance of bioenergy production, several agronomic and economic constraints still have to be overcome.” Don, A., Osborne, B., Hastings, A., Skiba, U., Carter, M. S., Drewer, J., Flessa, H., Freibauer, A., Hyvönen, N., Jones, M. B., Lanigan, G. J., Mander, Ü., Monti, A., Djomo, S. N., Valentine, J., Walter, K., Zegada-Lizarazu, W. and Zenone, T. (2012), Land-use change to bioenergy production in Europe: implications for the greenhouse gas balance and soil carbon. GCB Bioenergy, 4: 372–391. doi: 10.1111/j.1757-1707.2011.01116.x.

Global warming potential factors and warming payback time as climate indicators of forest biomass use – Pingoud et al. (2012) “A method is presented for estimating the global warming impact of forest biomass life cycles with respect to their functionally equivalent alternatives based on fossil fuels and non-renewable material sources. In the method, absolute global warming potentials (AGWP) of both the temporary carbon (C) debt of forest biomass stock and the C credit of the biomass use cycle displacing the fossil and non-renewable alternative are estimated as a function of the time frame of climate change mitigation. Dimensionless global warming potential (GWP) factors, GWPbio and GWPbiouse, are derived. As numerical examples, 1) bioenergy from boreal forest harvest residues to displace fossil fuels and 2) the use of wood for material substitution are considered. The GWP-based indicator leads to longer payback times, i.e. the time frame needed for the biomass option to be superior to its fossil-based alternative, than when just the cumulative balance of biogenic and fossil C stocks is considered. The warming payback time increases substantially with the residue diameter and low displacement factor (DF) of fossil C emissions. For the 35-cm stumps, the payback time appears to be more than 100 years in the climate conditions of Southern Finland when DF is lower than 0.5 in instant use and lower than 0.6 in continuous stump use. Wood use for construction appears to be more beneficial because, in addition to displaced emissions due to by-product bioenergy and material substitution, a significant part of round wood is sequestered into wood products for a long period, and even a zero payback time would be attainable with reasonable DFs.” Kim Pingoud, Tommi Ekholm, Ilkka Savolainen, Mitigation and Adaptation Strategies for Global Change, April 2012, Volume 17, Issue 4, pp 369-386, DOI: 10.1007/s11027-011-9331-9.

Forest Bioenergy or Forest Carbon? Assessing Trade-Offs in Greenhouse Gas Mitigation with Wood-Based Fuels – McKechnie et al. (2011) “The potential of forest-based bioenergy to reduce greenhouse gas (GHG) emissions when displacing fossil-based energy must be balanced with forest carbon implications related to biomass harvest. We integrate life cycle assessment (LCA) and forest carbon analysis to assess total GHG emissions of forest bioenergy over time. Application of the method to case studies of wood pellet and ethanol production from forest biomass reveals a substantial reduction in forest carbon due to bioenergy production. For all cases, harvest-related forest carbon reductions and associated GHG emissions initially exceed avoided fossil fuel-related emissions, temporarily increasing overall emissions. In the long term, electricity generation from pellets reduces overall emissions relative to coal, although forest carbon losses delay net GHG mitigation by 16−38 years, depending on biomass source (harvest residues/standing trees). Ethanol produced from standing trees increases overall emissions throughout 100 years of continuous production: ethanol from residues achieves reductions after a 74 year delay. Forest carbon more significantly affects bioenergy emissions when biomass is sourced from standing trees compared to residues and when less GHG-intensive fuels are displaced. In all cases, forest carbon dynamics are significant. Although study results are not generalizable to all forests, we suggest the integrated LCA/forest carbon approach be undertaken for bioenergy studies.” Jon McKechnie, Steve Colombo, Jiaxin Chen, Warren Mabee, and Heather L. MacLean, Environ. Sci. Technol., 2011, 45 (2), pp 789–795, DOI: 10.1021/es1024004. [Full text]

Paying for forest carbon or stimulating fuelwood demand? Insights from the French Forest Sector Model – Lecocq et al. (2011) “As European countries move towards steeper cuts in greenhouse gases emissions, questions are mounting, in the forest sector, about the best balance between policies that favor carbon sequestration in biomass, and policies that favor fossil-fuel substitution, with potentially conflicting implications for forest management. We provide insights on this debate by comparing the environmental and economic implications for the French forest sector of a “stock” policy (payment for sequestration in situ), a “substitution” policy (subsidy to fuelwood consumption), and a combination thereof – all calibrated on the same price of carbon. To do so, we use the French Forest Sector Model (FFSM), which combines a dynamic model of French timber resource and a dynamic partial-equilibrium model of the French forest sector. Simulations over the 2010–2020 period show that the stock policy is the only one that performs better than business-as-usual in terms of carbon. In the substitution policy, cumulative substitution benefits are not sufficient to offset carbon losses in standing forests over this biologically short, but politically relevant period of time. And the combination policy does not perform better. However, the stock policy has negative impacts on consumers welfare, its costs are increasing over time as carbon is accumulated, and it raises political economy questions about the negotiability of the reference against which excess carbon is measured.” Franck Lecocq, Sylvain Caurla, Philippe Delacote, Ahmed Barkaouia, Alexandre Sauquet, Journal of Forest Economics, Volume 17, Issue 2, April 2011, Pages 157–168, http://dx.doi.org/10.1016/j.jfe.2011.02.011.

Agricultural crop-based biofuels – resource efficiency and environmental performance including direct land use changes – Börjesson & Tufvesson (2011) “This paper analyses biofuels from agricultural crops in northern Europe regarding area and energy efficiency, greenhouse gases and eutrophication. The overall findings are that direct land use changes have a significant impact on GHG balances and eutrophication for all biofuels, the choice of calculation methods when by-products are included affecting the performance of food crop-based biofuels considerably, and the technical design of production systems may in specific cases be of major importance. The presented results are essential knowledge for the development of certification systems. Indirect land use changes are recognised but not included due to current scientific and methodological deficiencies.” Pål Börjesson, Linda M. Tufvesson, Journal of Cleaner Production, Volume 19, Issues 2–3, January–February 2011, Pages 108–120, http://dx.doi.org/10.1016/j.jclepro.2010.01.001.

Indirect carbon dioxide emissions from producing bioenergy from forest harvest residues – Repo et al. (2011) “Forest harvest residues are important raw materials for bioenergy in regions practicing forestry. Removing these residues from a harvest site reduces the carbon stock of the forest compared with conventional stem-only harvest because less litter in left on the site. The indirect carbon dioxide (CO2) emission from producing bioenergy occur when carbon in the logging residues is emitted into the atmosphere at once through combustion, instead of being released little by little as a result of decomposition at the harvest sites. In this study (1) we introduce an approach to calculate this indirect emission from using logging residues for bioenergy production, and (2) estimate this emission at a typical target of harvest residue removal, i.e. boreal Norway spruce forest in Finland. The removal of stumps caused a larger indirect emission per unit of energy produced than the removal of branches because of a lower decomposition rate of the stumps. The indirect emission per unit of energy produced decreased with time since starting to collect the harvest residues as a result of decomposition at older harvest sites. During the 100 years of conducting this practice, the indirect emission from average-sized branches (diameter 2 cm) decreased from 340 to 70 kg CO2 eq. MWh−1 and that from stumps (diameter 26 cm) from 340 to 160 kg CO2 eq. MWh−1. These emissions are an order of magnitude larger than the other emissions (collecting, transporting, etc.) from the bioenergy production chain. When the bioenergy production was started, the total emissions were comparable to fossil fuels. The practice had to be carried out for 22 (stumps) or four (branches) years until the total emissions dropped below the emissions of natural gas. Our results emphasize the importance of accounting for land-use-related indirect emissions to correctly estimate the efficiency of bioenergy in reducing CO2 emission into the atmosphere.” Repo, A., Tuomi, M. and Liski, J. (2011), Indirect carbon dioxide emissions from producing bioenergy from forest harvest residues. GCB Bioenergy, 3: 107–115. doi: 10.1111/j.1757-1707.2010.01065.x.

From the global efforts on certification of bioenergy towards an integrated approach based on sustainable land use planning – van Dam et al. (2010) “This paper presents an overview of 67 ongoing certification initiatives to safeguard the sustainability of bioenergy. Most recent initiatives are focused on the sustainability of liquid biofuels. Content-wise, most of these initiatives have mainly included environmental principles. Despite serious concerns in various parts of the world on the socio-economic impacts of bioenergy production, these are generally not included in existing bioenergy initiatives. At the same time, the overview shows a strong proliferation of standards. The overview shows that certification has the potential to influence direct, local impacts related to environmental and social effects of direct bioenergy production. Key recommendations to come to an efficient certification system include the need for further harmonization, availability of reliable data and linking indicators on a micro, meso and macro levels. Considering the multiple spatial scales, certification should be combined with additional measurements and tools on a regional, national and international level. The role of bioenergy production on indirect land use change (ILUC) is still very uncertain and current initiatives have rarely captured impacts from ILUC in their standards. Addressing unwanted LUC requires first of all sustainable land use production and good governance, regardless of the end-use of the product. It is therefore recommended to extend measures to mitigate impacts from LUC to other lands and feedstock.” J. van Dam, M. Junginger, A.P.C. Faaij, Renewable and Sustainable Energy Reviews, Volume 14, Issue 9, December 2010, Pages 2445–2472, http://dx.doi.org/10.1016/j.rser.2010.07.010.

Greenhouse Gas Emissions from Biofuels’ Indirect Land Use Change Are Uncertain but May Be Much Greater than Previously Estimated – Plevin et al. (2010) “The life cycle greenhouse gas (GHG) emissions induced by increased biofuel consumption are highly uncertain: individual estimates vary from each other and each has a wide intrinsic error band. Using a reduced-form model, we estimated that the bounding range for emissions from indirect land-use change (ILUC) from US corn ethanol expansion was 10 to 340 g CO2 MJ−1. Considering various probability distributions to model parameters, the broadest 95% central interval, i.e., between the 2.5 and 97.5%ile values, ranged from 21 to 142 g CO2e MJ−1. ILUC emissions from US corn ethanol expansion thus range from small, but not negligible, to several times greater than the life cycle emissions of gasoline. The ILUC emissions estimates of 30 g CO2 MJ−1 for the California Air Resources Board and 34 g CO2e MJ−1 by USEPA (for 2022) are at the low end of the plausible range. The lack of data and understanding (epistemic uncertainty) prevents convergence of judgment on a central value for ILUC emissions. The complexity of the global system being modeled suggests that this range is unlikely to narrow substantially in the near future. Fuel policies that require narrow bounds around point estimates of life cycle GHG emissions are thus incompatible with current and anticipated modeling capabilities. Alternative policies that address the risks associated with uncertainty are more likely to achieve GHG reductions.” Richard J. Plevin, Michael O’Hare, Andrew D. Jones, Margaret S. Torn, and Holly K. Gibbs, Environ. Sci. Technol., 2010, 44 (21), pp 8015–8021, DOI: 10.1021/es101946t. [Full text]

Effects of US Maize Ethanol on Global Land Use and Greenhouse Gas Emissions: Estimating Market-Mediated Responses – Hertel et al. (2010) “Releases of greenhouse gases (GHG) from indirect land-use change triggered by crop-based biofuels have taken center stage in the debate over the role of biofuels in climate policy and energy security. This article analyzes these releases for maize ethanol produced in the United States. Factoring market-mediated responses and by-product use into our analysis reduces cropland conversion by 72% from the land used for the ethanol feedstock. Consequently, the associated GHG release estimated in our framework is 800 grams of carbon dioxide per megajoule (MJ); 27 grams per MJ per year, over 30 years of ethanol production, or roughly a quarter of the only other published estimate of releases attributable to changes in indirect land use. Nonetheless, 800 grams are enough to cancel out the benefits that corn ethanol has on global warming, thereby limiting its potential contribution in the context of California’s Low Carbon Fuel Standard.” Thomas W. Hertel , Alla A. Golub , Andrew D. Jones , Michael O’Hare , Richard J. Plevin and Daniel M. Kammen, BioScience 60(3):223-231. 2010, doi: http://dx.doi.org/10.1525/bio.2010.60.3.8. [Full text]

Direct and indirect land-use competition issues for energy crops and their sustainable production – an overview – Fritsche et al. (2010) “Biofuel production from energy crops is land-use intensive. Land-use change (LUC) associated with bioenergy cropping impacts on the greenhouse gas (GHG) balance, both directly and indirectly. Land-use conversion can also impact on biodiversity. The current state of quantifying GHG emissions relating to direct and indirect land-use change (iLUC) from biomass produced for liquid biofuels or bioenergy is reviewed. Several options for reducing iLUC are discussed, and recommendations made for considering LUC in bioenergy and biofuel policies. Land used for energy cropping is subject to competing demands for conventional agriculture and forest production, as well as for nature protection and conservation. Biomass to be used for bioenergy and biofuels should therefore be produced primarily from excess farm and forest residues or from land not required for food and fiber production. The overall efficiency of biomass production, conversion, and use should be increased where possible in order to further reduce land competition and the related direct and iLUC risks. This review of several varying approaches to iLUC substantiates that, in principle, GHG emissions can be quantified and reductions implemented by appropriate policies. Such approaches can (and should) be refined and substantiated using better data on direct LUC trends from global monitoring, and be further improved by adding more accurate estimates of future trade patterns where appropriate. This brief discussion of current policies and options to reduce iLUC has identified a variety of approaches and options so that a quantified iLUC factor could be translated into practical regulations – both mandatory and voluntary – with few restrictions. Depending on the future development of energy cropping systems and yield improvements, sustainable bioenergy production could make a significant contribution to the future global energy demand.” Fritsche, U. R., Sims, R. E. H. and Monti, A. (2010), Direct and indirect land-use competition issues for energy crops and their sustainable production – an overview. Biofuels, Bioprod. Bioref., 4: 692–704. doi: 10.1002/bbb.258. [Full text]

Proper accounting for time increases crop-based biofuels’ greenhouse gas deficit versus petroleum – O’Hare et al. (2009) “The global warming intensities of crop-based biofuels and fossil fuels differ not only in amount but also in their discharge patterns over time. Early discharges, for example, from market-mediated land use change, will have created more global warming by any time in the future than later discharges, owing to the slow decay of atmospheric CO2. A spreadsheet model of this process, BTIME, captures this important time pattern effect using the Bern CO2 decay model to allow fuels to be compared for policy decisions on the basis of their real warming effects with a variety of user-supplied parameter values. The model also allows economic discounting of climate effects extended far into the future. Compared to approaches that simply sum greenhouse gas emissions over time, recognizing the physics of atmospheric CO2 decay significantly increases the deficit relative to fossil fuel of any biofuel causing land use change.” M O’Hare et al 2009 Environ. Res. Lett. 4 024001 doi:10.1088/1748-9326/4/2/024001. [Full text]


Set-asides can be better climate investment than corn ethanol – Piñeiro et al. (2009)

Although various studies have shown that corn ethanol reduces greenhouse gas (GHG) emissions by displacing fossil fuel use, many of these studies fail to include how land-use history affects the net carbon balance through changes in soil carbon content. We evaluated the effectiveness and economic value of corn and cellulosic ethanol production for reducing net GHG emissions when produced on lands with different land-use histories, comparing these strategies with reductions achieved by set-aside programs such as the Conservation Reserve Program (CRP). Depending on prior land use, our analysis shows that C releases from the soil after planting corn for ethanol may in some cases completely offset C gains attributed to biofuel generation for at least 50 years. More surprisingly, based on our comprehensive analysis of 142 soil studies, soil C sequestered by setting aside former agricultural land was greater than the C credits generated by planting corn for ethanol on the same land for 40 years and had equal or greater economic net present value. Once commercially available, cellulosic ethanol produced in set-aside grasslands should provide the most efficient tool for GHG reduction of any scenario we examined. Our results suggest that conversion of CRP lands or other set-aside programs to corn ethanol production should not be encouraged through greenhouse gas policies.” Gervasio Piñeiro, Esteban G. Jobbágy, Justin Baker, Brian C. Murray, and Robert B. Jackson 2009. Set-asides can be better climate investment than corn ethanol. Ecological Applications 19:277–282. http://dx.doi.org/10.1890/08-0645.1. [Full text]

Biofuel Plantations on Forested Lands: Double Jeopardy for Biodiversity and Climate – Danielsen et al. (2009) “The growing demand for biofuels is promoting the expansion of a number of agricultural commodities, including oil palm (Elaeis guineensis). Oil-palm plantations cover over 13 million ha, primarily in Southeast Asia, where they have directly or indirectly replaced tropical rainforest. We explored the impact of the spread of oil-palm plantations on greenhouse gas emission and biodiversity. We assessed changes in carbon stocks with changing land use and compared this with the amount of fossil-fuel carbon emission avoided through its replacement by biofuel carbon. We estimated it would take between 75 and 93 years for the carbon emissions saved through use of biofuel to compensate for the carbon lost through forest conversion, depending on how the forest was cleared. If the original habitat was peatland, carbon balance would take more than 600 years. Conversely, planting oil palms on degraded grassland would lead to a net removal of carbon within 10 years. These estimates have associated uncertainty, but their magnitude and relative proportions seem credible. We carried out a meta-analysis of published faunal studies that compared forest with oil palm. We found that plantations supported species-poor communities containing few forest species. Because no published data on flora were available, we present results from our sampling of plants in oil palm and forest plots in Indonesia. Although the species richness of pteridophytes was higher in plantations, they held few forest species. Trees, lianas, epiphytic orchids, and indigenous palms were wholly absent from oil-palm plantations. The majority of individual plants and animals in oil-palm plantations belonged to a small number of generalist species of low conservation concern. As countries strive to meet obligations to reduce carbon emissions under one international agreement (Kyoto Protocol), they may not only fail to meet their obligations under another (Convention on Biological Diversity) but may actually hasten global climate change. Reducing deforestation is likely to represent a more effective climate-change mitigation strategy than converting forest for biofuel production, and it may help nations meet their international commitments to reduce biodiversity loss.” Danielsen, F., Beukema, H., Burgess, N. D., Parish, F., Brühl, C. A., Donald, P. F., Murdiyarso, D., Phalan, B., Reijnders, L., Struebig, M. and Fitzherbert, E. B. (2009), Biofuel Plantations on Forested Lands: Double Jeopardy for Biodiversity and Climate. Conservation Biology, 23: 348–358. doi: 10.1111/j.1523-1739.2008.01096.x. [Full text]

Carbon payback times for crop-based biofuel expansion in the tropics: the effects of changing yield and technology – Gibbs et al. (2008) “Biofuels from land-rich tropical countries may help displace foreign petroleum imports for many industrialized nations, providing a possible solution to the twin challenges of energy security and climate change. But concern is mounting that crop-based biofuels will increase net greenhouse gas emissions if feedstocks are produced by expanding agricultural lands. Here we quantify the ‘carbon payback time’ for a range of biofuel crop expansion pathways in the tropics. We use a new, geographically detailed database of crop locations and yields, along with updated vegetation and soil biomass estimates, to provide carbon payback estimates that are more regionally specific than those in previous studies. Using this cropland database, we also estimate carbon payback times under different scenarios of future crop yields, biofuel technologies, and petroleum sources. Under current conditions, the expansion of biofuels into productive tropical ecosystems will always lead to net carbon emissions for decades to centuries, while expanding into degraded or already cultivated land will provide almost immediate carbon savings. Future crop yield improvements and technology advances, coupled with unconventional petroleum supplies, will increase biofuel carbon offsets, but clearing carbon-rich land still requires several decades or more for carbon payback. No foreseeable changes in agricultural or energy technology will be able to achieve meaningful carbon benefits if crop-based biofuels are produced at the expense of tropical forests.” Holly K Gibbs et al 2008 Environ. Res. Lett. 3 034001 doi:10.1088/1748-9326/3/3/034001. [Full text]

Land Clearing and the Biofuel Carbon Debt – Fargione et al. (2008) “Increasing energy use, climate change, and carbon dioxide (CO2) emissions from fossil fuels make switching to low-carbon fuels a high priority. Biofuels are a potential low-carbon energy source, but whether biofuels offer carbon savings depends on how they are produced. Converting rainforests, peatlands, savannas, or grasslands to produce food crop–based biofuels in Brazil, Southeast Asia, and the United States creates a “biofuel carbon debt” by releasing 17 to 420 times more CO2 than the annual greenhouse gas (GHG) reductions that these biofuels would provide by displacing fossil fuels. In contrast, biofuels made from waste biomass or from biomass grown on degraded and abandoned agricultural lands planted with perennials incur little or no carbon debt and can offer immediate and sustained GHG advantages.” Joseph Fargione, Jason Hill, David Tilman, Stephen Polasky, Peter Hawthorne, Science 29 February 2008: Vol. 319 no. 5867 pp. 1235-1238, DOI: 10.1126/science.1152747. [Full text]

Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change – Searchinger et al. (2008) “Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products.” Timothy Searchinger, Ralph Heimlich, R. A. Houghton, Fengxia Dong, Amani Elobeid, Jacinto Fabiosa, Simla Tokgoz, Dermot Hayes, Tun-Hsiang Yu, Science 29 February 2008: Vol. 319 no. 5867 pp. 1238-1240, DOI: 10.1126/science.1151861. [Full text]

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Papers on wind turbine noise

Posted by Ari Jokimäki on November 6, 2012

This is a list of papers on wind turbine noise. The list is not complete, and will most likely be updated in future in order to make it more thorough and more representative.

Update (November 13, 2012): Hubbard & Shepherd (1991), Jakobsen (2005), Pedersen & Larsman (2008), Pedersen et al. (2009), Hessler et al. (2008), Knopper & Ollson (2011), and Bolin et al. (2011) added. Thanks to Martin for pointing these out (in private communication).
Update (November 7, 2012): Taylor et al. (2012) added.

The influence of negative oriented personality traits on the effects of wind turbine noise – Taylor et al. (2012) “Concern about invisible environmental agents from new technologies, such as radiation, radio-waves, and odours, have been shown to act as a trigger for reports of ill health. However, recently, it has been suggested that wind turbines – an archetypal green technology, are a new culprit in explanations of medically unexplained non-specific symptoms (NSS): the so-called Wind Turbine Syndrome (Pierpont, 2009). The current study assesses the effect of negative orientated personality (NOP) traits (Neuroticism, Negative Affectivity and Frustration Intolerance) on the relationship between both actual and perceived noise on NSS. All households near ten small and micro wind turbines in two UK cities completed measures of perceived turbine noise, Neuroticism, Negative Affectivity, Frustration Intolerance, attitude to wind turbines, and NSS (response N = 138). Actual turbine noise level for each household was also calculated. There was no evidence for the effect of calculated actual noise on NSS. The relationship between perceived noise and NSS was only found for individuals high in NOP traits the key role of individual differences in the link between perceived (but not actual) environmental characteristics and symptom reporting. This is the first study to show this effect in relation to a so called ‘green technology’.” Jennifer Taylor, Carol Eastwick, Robin Wilson, Claire Lawrence, Personality and Individual Differences, http://dx.doi.org/10.1016/j.paid.2012.09.018.

Effects of industrial wind turbine noise on sleep and health – Nissenbaum et al. (2012) “Industrial wind turbines (IWTs) are a new source of noise in previously quiet rural environments. Environmental noise is a public health concern, of which sleep disruption is a major factor. To compare sleep and general health outcomes between participants living close to IWTs and those living further away from them, participants living between 375 and 1400 m (n = 38) and 3.3 and 6.6 km (n = 41) from IWTs were enrolled in a stratified cross-sectional study involving two rural sites. Validated questionnaires were used to collect information on sleep quality (Pittsburgh Sleep Quality Index – PSQI), daytime sleepiness (Epworth Sleepiness Score – ESS), and general health (SF36v2), together with psychiatric disorders, attitude, and demographics. Descriptive and multivariate analyses were performed to investigate the effect of the main exposure variable of interest (distance to the nearest IWT) on various health outcome measures. Participants living within 1.4 km of an IWT had worse sleep, were sleepier during the day, and had worse SF36 Mental Component Scores compared to those living further than 1.4 km away. Significant dose-response relationships between PSQI, ESS, SF36 Mental Component Score, and log-distance to the nearest IWT were identified after controlling for gender, age, and household clustering. The adverse event reports of sleep disturbance and ill health by those living close to IWTs are supported.” Michael A Nissenbaum, Jeffery J Aramini, Christopher D Hanning, Noise & Health, 2012, 14, 60, 237-243, DOI: 10.4103/1463-1741.102961.

Infrasound and low frequency noise from wind turbines: exposure and health effects – Bolin et al. (2011) “Wind turbines emit low frequency noise (LFN) and large turbines generally generate more LFN than small turbines. The dominant source of LFN is the interaction between incoming turbulence and the blades. Measurements suggest that indoor levels of LFN in dwellings typically are within recommended guideline values, provided that the outdoor level does not exceed corresponding guidelines for facade exposure. Three cross-sectional questionnaire studies show that annoyance from wind turbine noise is related to the immission level, but several explanations other than low frequency noise are probable. A statistically significant association between noise levels and self-reported sleep disturbance was found in two of the three studies. It has been suggested that LFN from wind turbines causes other, and more serious, health problems, but empirical support for these claims is lacking.” Karl Bolin et al 2011 Environ. Res. Lett. 6 035103 doi:10.1088/1748-9326/6/3/035103. [FULL TEXT]

Health effects and wind turbines: A review of the literature – Knopper & Ollson (2011) “Background: Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet. Methods: The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of KnowledgeSM and the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions. Results: Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured. Conclusions: What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted.” Loren D Knopper and Christopher A Ollson, Environmental Health 2011, 10:78 doi:10.1186/1476-069X-10-78. [FULL TEXT]

Evaluating the impact of wind turbine noise on health-related quality of life – Shepherd et al. (2011) “We report a cross-sectional study comparing the health-related quality of life (HRQOL) of individuals residing in the proximity of a wind farm to those residing in a demographically matched area sufficiently displaced from wind turbines. The study employed a nonequivalent comparison group posttest-only design. Self-administered questionnaires, which included the brief version of the World Health Organization quality of life scale, were delivered to residents in two adjacent areas in semirural New Zealand. Participants were also asked to identify annoying noises, indicate their degree of noise sensitivity, and rate amenity. Statistically significant differences were noted in some HRQOL domain scores, with residents living within 2 km of a turbine installation reporting lower overall quality of life, physical quality of life, and environmental quality of life. Those exposed to turbine noise also reported significantly lower sleep quality, and rated their environment as less restful. Our data suggest that wind farm noise can negatively impact facets of HRQOL.” Daniel Shepherd, David McBride, David Welch, Kim N Dirks, Erin M Hill, Noise & Health, 2011, 13, 54, 333-339, DOI: 10.4103/1463-1741.85502. [FULL TEXT]

Low-frequency noise from large wind turbines – Møller & Pedersen (2011) “As wind turbines get larger, worries have emerged that the turbine noise would move down in frequency and that the low-frequency noise would cause annoyance for the neighbors. The noise emission from 48 wind turbines with nominal electric power up to 3.6 MW is analyzed and discussed. The relative amount of low-frequency noise is higher for large turbines (2.3–3.6 MW) than for small turbines (≤ 2 MW), and the difference is statistically significant. The difference can also be expressed as a downward shift of the spectrum of approximately one-third of an octave. A further shift of similar size is suggested for future turbines in the 10-MW range. Due to the air absorption, the higher low-frequency content becomes even more pronounced, when sound pressure levels in relevant neighbor distances are considered. Even when A-weighted levels are considered, a substantial part of the noise is at low frequencies, and for several of the investigated large turbines, the one-third-octave band with the highest level is at or below 250 Hz. It is thus beyond any doubt that the low-frequency part of the spectrum plays an important role in the noise at the neighbors.” Henrik Møller and Christian Sejer Pedersen, J. Acoust. Soc. Am. Volume 129, Issue 6, pp. 3727-3744, http://dx.doi.org/10.1121/1.3543957. [FULL TEXT]

Wind Turbine Noise – Harrison (2011) “Following an introduction to noise and noise regulation of wind turbines, the problem of adverse health effects of turbine noise is discussed. This is attributed to the characteristics of turbine noise and deficiencies in the regulation of this noise. Both onshore and offshore wind farms are discussed.” John P. Harrison, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 256-261, doi: 10.1177/0270467611412549. [FULL TEXT]

The Problems With “Noise Numbers” for Wind Farm Noise Assessment – Thorne (2011) “Human perception responds primarily to sound character rather than sound level. Wind farms are unique sound sources and exhibit special audible and inaudible characteristics that can be described as modulating sound or as a tonal complex. Wind farm compliance measures based on a specified noise number alone will fail to address problems with noise nuisance. The character of wind farm sound, noise emissions from wind farms, noise prediction at residences, and systemic failures in assessment processes are examined. Human perception of wind farm sound is compared with noise assessment measures and complaint histories. The adverse effects on health of persons susceptible to noise from wind farms are examined and a hypothesis, the concept of heightened noise zones (pressure variations), as a marker for cause and effect is advanced. A sound level of LAeq 32 dB outside a residence and above an individual’s threshold of hearing inside the home are identified as markers for serious adverse health effects affecting susceptible individuals. The article is referenced to the author’s research, measurements, and observations at different wind farms in New Zealand and Victoria, Australia.” Bob Thorne, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 262-290, doi: 10.1177/0270467611412557.

The Noise From Wind Turbines: Potential Adverse Impacts on Children’s Well-Being – Bronzaft (2011) “Research linking loud sounds to hearing loss in youngsters is now widespread, resulting in the issuance of warnings to protect children’s hearing. However, studies attesting to the adverse effects of intrusive sounds and noise on children’s overall mental and physical health and well-being have not received similar attention.This, despite the fact that many studies have demonstrated that intrusive noises such as those from passing road traffic, nearby rail systems, and overhead aircraft can adversely affect children’s cardiovascular system, memory, language development, and learning acquisition. While some schools in the United States have received funds to abate intrusive aircraft noise, for example, many schools still expose children to noises from passing traffic and overhead aircraft. Discussion focuses on the harmful effects of noise on children, what has to be done to remedy the situation, and the need for action to lessen the impacts of noise from all sources. Furthermore, based on our knowledge of the harmful effects of noise on children’s health and the growing body of evidence to suggest the potential harmful effects of industrial wind turbine noise, it is strongly urged that further studies be conducted on the impacts of industrial wind turbines on their health, as well as the health of their parents, before forging ahead in siting industrial wind turbines.” Arline L. Bronzaft, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 291-295, doi: 10.1177/0270467611412548. [FULL TEXT]

Infrasound From Wind Turbines Could Affect Humans – Salt & Kaltenbach (2011) “Wind turbines generate low-frequency sounds that affect the ear. The ear is superficially similar to a microphone, converting mechanical sound waves into electrical signals, but does this by complex physiologic processes. Serious misconceptions about low-frequency sound and the ear have resulted from a failure to consider in detail how the ear works. Although the cells that provide hearing are insensitive to infrasound, other sensory cells in the ear are much more sensitive, which can be demonstrated by electrical recordings. Responses to infrasound reach the brain through pathways that do not involve conscious hearing but instead may produce sensations of fullness, pressure or tinnitus, or have no sensation. Activation of subconscious pathways by infrasound could disturb sleep. Based on our current knowledge of how the ear works, it is quite possible that low-frequency sounds at the levels generated by wind turbines could affect those living nearby.” Alec N. Salt, James A. Kaltenbach, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 296-302, doi: 10.1177/0270467611412555.

Properly Interpreting the Epidemiologic Evidence About the Health Effects of Industrial Wind Turbines on Nearby Residents – Phillips (2011) “There is overwhelming evidence that wind turbines cause serious health problems in nearby residents, usually stress-disorder-type diseases, at a nontrivial rate. The bulk of the evidence takes the form of thousands of adverse event reports. There is also a small amount of systematically gathered data. The adverse event reports provide compelling evidence of the seriousness of the problems and of causation in this case because of their volume, the ease of observing exposure and outcome incidence, and case-crossover data. Proponents of turbines have sought to deny these problems by making a collection of contradictory claims including that the evidence does not “count,” the outcomes are not “real” diseases, the outcomes are the victims’ own fault, and that acoustical models cannot explain why there are health problems so the problems must not exist. These claims appeared to have swayed many nonexpert observers, though they are easily debunked. Moreover, though the failure of models to explain the observed problems does not deny the problems, it does mean that we do not know what, other than kilometers of distance, could sufficiently mitigate the effects. There has been no policy analysis that justifies imposing these effects on local residents. The attempts to deny the evidence cannot be seen as honest scientific disagreement and represent either gross incompetence or intentional bias.” Carl V. Phillips, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 303-315, doi: 10.1177/0270467611412554. [FULL TEXT]

Toward a Case Definition of Adverse Health Effects in the Environs of Industrial Wind Turbines: Facilitating a Clinical Diagnosis – McMurtry (2011) “Internationally, there are reports of adverse health effects (AHE) in the environs of industrial wind turbines (IWT). There was multidisciplinary confirmation of the key characteristics of the AHE at the first international symposium on AHE/IWT. The symptoms being reported are consistent internationally and are characterized by crossover findings or a predictable appearance of signs and symptoms present with exposure to IWT sound energy and amelioration when the exposure ceases. There is also a revealed preference of victims to seek restoration away from their homes. This article identifies the need to create a case definition to establish a clinical diagnosis. A case definition is proposed that identifies the sine qua non diagnostic criteria for a diagnosis of adverse health effects in the environs of industrial wind turbines. Possible, probable, and confirmed diagnoses are detailed. The goal is to foster the adoption of a common case definition that will facilitate future research efforts.” Robert Y. McMurtry, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 316-320, doi: 10.1177/0270467611415075. [FULL TEXT]

Industrial Wind Turbine Development and Loss of Social Justice? – Krogh (2011) “This article explores the loss of social justice reported by individuals living in the environs of industrial wind turbines (IWTs). References indicate that some individuals residing in proximity to IWT facilities experience adverse health effects. These adverse health effects are severe enough that some families have abandoned their homes. Individuals report they welcomed IWTs into their community and the negative consequences were unexpected. Expressions of grief are exacerbated by the emotional and physical toll of individuals’ symptoms, loss of enjoyment of homes and property, disturbed living conditions, financial loss, and the lack of society’s recognition of their situation. The author has investigated the reported loss of social justice through a review of literature, personal interviews with, and communications from, those reporting adverse health effects. The author’s intention is to create awareness that loss of social justice is being associated with IWT development. This loss of justice arises from a number of factors, including the lack of fair process, the loss of rights, and associated disempowerment. These societal themes require further investigation. Research by health professionals and social scientists is urgently needed to address the health and social impacts of IWTs operating near family homes.” Carmen M. E. Krogh, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 321-333, doi: 10.1177/0270467611412550.

WindVOiCe, a Self-Reporting Survey: Adverse Health Effects, Industrial Wind Turbines, and the Need for Vigilance Monitoring – Krogh et al. (2011) “Industrial wind turbines have been operating in many parts of the globe. Anecdotal reports of perceived adverse health effects relating to industrial wind turbines have been published in the media and on the Internet. Based on these reports, indications were that some residents perceived they were experiencing adverse health effects. The purpose of the WindVOiCe health survey was to provide vigilance monitoring for those wishing to report their perceived adverse health effects. This article discusses the results of a self reporting health survey regarding perceived adverse health effects associated with industrial wind turbines.” Carmen M.E. Krogh, Lorrie Gillis, Nicholas Kouwen, Jeff Aramini, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 334-345, doi: 10.1177/0270467611412551.

Can road traffic mask sound from wind turbines? Response to wind turbine sound at different levels of road traffic sound – Pedersen et al. (2010) “Wind turbines are favoured in the switch-over to renewable energy. Suitable sites for further developments could be difficult to find as the sound emitted from the rotor blades calls for a sufficient distance to residents to avoid negative effects. The aim of this study was to explore if road traffic sound could mask wind turbine sound or, in contrast, increases annoyance due to wind turbine noise. Annoyance of road traffic and wind turbine noise was measured in the WINDFARMperception survey in the Netherlands in 2007 (n=725) and related to calculated levels of sound. The presence of road traffic sound did not in general decrease annoyance with wind turbine noise, except when levels of wind turbine sound were moderate (35–40 dB(A) Lden) and road traffic sound level exceeded that level with at least 20 dB(A). Annoyance with both noises was intercorrelated but this correlation was probably due to the influence of individual factors. Furthermore, visibility and attitude towards wind turbines were significantly related to noise annoyance of modern wind turbines. The results can be used for the selection of suitable sites, possibly favouring already noise exposed areas if wind turbine sound levels are sufficiently low.” Eja Pedersen, Frits van den Berg, Roel Bakker, Jelte Bouma, Energy Policy, Volume 38, Issue 5, May 2010, Pages 2520–2527, http://dx.doi.org/10.1016/j.enpol.2010.01.001. [FULL TEXT]

Response to noise from modern wind farms in The Netherlands – Pedersen et al. (2009) “The increasing number and size of wind farms call for more data on human response to wind turbine noise, so that a generalized dose-response relationship can be modeled and possible adverse health effects avoided. This paper reports the results of a 2007 field study in The Netherlands with 725 respondents. A dose-response relationship between calculated A-weighted sound pressure levels and reported perception and annoyance was found. Wind turbine noise was more annoying than transportation noise or industrial noise at comparable levels, possibly due to specific sound properties such as a “swishing” quality, temporal variability, and lack of nighttime abatement. High turbine visibility enhances negative response, and having wind turbines visible from the dwelling significantly increased the risk of annoyance. Annoyance was strongly correlated with a negative attitude toward the visual impact of wind turbines on the landscape. The study further demonstrates that people who benefit economically from wind turbines have a significantly decreased risk of annoyance, despite exposure to similar sound levels. Response to wind turbine noise was similar to that found in Sweden so the dose-response relationship should be generalizable.” Eja Pedersen, Frits van den Berg, Roel Bakker, and Jelte Bouma, J. Acoust. Soc. Am. Volume 126, Issue 2, pp. 634-643 (2009), DOI: http://dx.doi.org/10.1121/1.3160293. [FULL TEXT]

The impact of visual factors on noise annoyance among people living in the vicinity of wind turbines – Pedersen & Larsman (2008) “Wind turbines are highly visible objects and the response to wind turbine noise is possibly influenced by visual factors. In this study, visibility of the noise source, visual attitude and vertical visual angle (VVA) in different landscapes were explored. Data from two cross-sectional field studies carried out among people living near wind turbines (n=1095) were used for structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see vs. respondents who could not see wind turbines from their homes, living in flat vs. hilly/rocky terrain, and living in built-up vs. rural areas. Visual attitude towards the noise source was associated with noise annoyance to different degrees in different situations. A negative visual attitude, more than multi-modal effects between auditory and visual stimulation, enhanced the risk for noise annoyance and possibly also prevented psychophysiological restoration possibilities. Aesthetic evaluations of the noise source should be taken into account when exploring response to environmental noise.” Eja Pedersen, Pernilla Larsman, Journal of Environmental Psychology, Volume 28, Issue 4, December 2008, Pages 379–389, http://dx.doi.org/10.1016/j.jenvp.2008.02.009.

Experimental study to determine wind-induced noise and windscreen attenuation effects on microphone response for environmental wind turbine and other applications – Hessler et al. (2008) “Despite the use of windscreens, the measurement of ambient sound levels or noise emissions in quiet environments can be adversely affected by wind blowing over the microphone. This is especially true when environmental impact assessments are being carried out for proposed wind turbine power projects – where the objective is to determine the level of background masking noise available as a function of wind speed, since any potential noise impact from the project will only occur under moderately windy conditions. Under calm conditions the project will produce no noise at all. A number of windscreen products are commercially available for short and long-term sound level monitoring in adverse weather conditions. Generally, these windscreens vary by physical size and the method of preventing water from reaching the microphone. High frequency attenuation effects are usually available from the product suppliers but, in general, low frequency turbulence effects are not available. Consequently, a controlled laboratory test program was carried out in a state-of-the-art wind tunnel at the Fraunhofer Institut fu¨r Bauphysik in Stuttgart, Germany to quantify the level of low frequency interference (down to 6.3 Hz) associated with a number of different foam windscreens and an aerodynamic microphone nose cone. A total of nine configurations were tested with “quiet“ airflow only, artificial noise only and noise plus airflow to evaluate both low frequency wind induced noise and high frequency attenuation effects. The test program demonstrated that the largest size foam-based windscreens provided the most protection from flow induced noise due to wind. Flow induced noise by air flow alone was estimated from the study results and compared to community noise measurements at a typical wind turbine site. It was determined that flow induced wind noise does not have a significant or detrimental effect on the measurement of A-weighted sound levels under wind conditions of concern as long as the suggested measurement techniques described herein are followed.” Hessler, George F.; Hessler, David M.; Brandsta¨tt, Peter; Bay, Karlheinz, Noise Control Engineering Journal, Volume 56, Number 4, 1 July 2008 , pp. 300-309(10), DOI: http://dx.doi.org/10.3397/1.2949926.

Wind turbine noise, annoyance and self-reported health and well-being in different living environments – Pedersen & Waye (2007) “Objectives: To evaluate the prevalence of perception and annoyance due to wind turbine noise among people living near the turbines, and to study relations between noise and perception/annoyance, with focus on differences between living environments. Methods: A cross-sectional study was carried out in seven areas in Sweden across dissimilar terrain and different degrees of urbanisation. A postal questionnaire regarding living conditions including response to wind turbine noise was completed by 754 subjects. Outdoor A-weighted sound pressure levels (SPLs) were calculated for each respondent. Perception and annoyance due to wind turbine noise in relation to SPLs was analysed with regard to dissimilarities between the areas. Results: The odds of perceiving wind turbine noise increased with increasing SPL (OR 1.3; 95% CI 1.25 to 1.40). The odds of being annoyed by wind turbine noise also increased with increasing SPLs (OR 1.1; 95% CI 1.01 to 1.25). Perception and annoyance were associated with terrain and urbanisation: (1) a rural area increased the risk of perception and annoyance in comparison with a suburban area; and (2) in a rural setting, complex ground (hilly or rocky terrain) increased the risk compared with flat ground. Annoyance was associated with both objective and subjective factors of wind turbine visibility, and was further associated with lowered sleep quality and negative emotions. Conclusion: There is a need to take the unique environment into account when planning a new wind farm so that adverse health effects are avoided. The influence of area-related factors should also be considered in future community noise research.” Eja Pedersen, Kerstin Persson Waye, Occup Environ Med 2007;64:480-486, doi:10.1136/oem.2006.031039. [FULL TEXT]

Living in the Vicinity of Wind Turbines — A Grounded Theory Study – Pedersen et al. (2007) “Little is known of wind turbines’ impact on people living in their vicinity. The aim of this study was to gain a deeper understanding of how people perceive and are affected by wind turbines in their living environment. In-depth interviews with 15 informants, strategically chosen to form a heterogeneous group, were analyzed using the constant comparative method of grounded theory. The informants were to different extents affected by the swishing noise, flickering light, and constant movement of the turbines’ rotor blades. Some informants perceived the exposures as outside their territory while others perceived them as intrusion into privacy; a divergence partly determined by the informants’ personal values about the living environment. The feeling of intrusion was associated with feeling a lack of control, subjected to injustice, a lack of influence, and not being believed. Informants used various coping strategies, such as rebuilding their houses or complaining, but mainly tried to ignore exposures from the wind turbines. The findings can help us to better understand the severe reactions wind turbines sometimes evoke and contribute to the knowledge base used when planning for new wind farms.” E. Pedersen, LR-M. Hallberg & K.P. Waye, Qualitative Research in Psychology, Volume 4, Issue 1-2, 2007, DOI:10.1080/14780880701473409.

Perception of low-frequency acoustic signals by a harbour porpoise (Phocoena phocoena) in the presence of simulated offshore wind turbine noise – Lucke et al. (2007) “Using auditory evoked potential (AEP) methods, a study was conducted on a harbour porpoise (Phocoena phocoena) at the Dolfinarium Harderwijk in The Netherlands. The study measured the audible range of wind turbine sounds and their potential masking effects on the acoustic perception of the animal. AEPs were evoked with two types of acoustic stimuli: (1) click-type signals and (2) amplitude-modulated signals. The masking noise resembling the underwater sound emissions of an operational wind turbine was simulated. At first, the animal’s hearing threshold was measured at frequencies between 0.7 and 16 kHz. Subsequently, these measurements were repeated at frequencies between 0.7 and 2.8 kHz in the presence of two different levels of masking noise. The resulting data show a masking effect of the simulated wind turbine sound at 128 dB re 1 μPa at 0.7, 1.0, and 2.0 kHz. This masking effect varied between 4.8 and 7.3 dB at those frequencies. No significant masking was measured at a masking level of 115 dB re 1 μPa. The available data indicate that the potential masking effect would be limited to short ranges in the open sea, but limitations exist to this conclusion and all estimates are based on existing turbine types, not taking into account future developments of larger and potentially noisier turbine types.” Lucke, Klaus, Lepper, Paul A., Hoeve, Bert, Everaarts, Eligius, van Elk, Niels, Siebert, Ursula, Aquatic Mammals, 33 (1), pp. 55-68, DOI 10.1578/AM.33.1.2007.55. [FULL TEXT]

Location and quantification of noise sources on a wind turbine – Oerlemans et al. (2007) “Acoustic field measurements were carried out on a three-bladed wind turbine with a rotor diameter of 58 m, in order to characterize the noise sources and to verify whether trailing edge noise from the blades was dominant. To assess the effect of blade roughness, one blade was cleaned, one blade was tripped, and one blade remained untreated. A large horizontal microphone array, positioned about one rotor diameter upwind from the turbine, was used to measure the distribution of the noise sources in the rotor plane and on the individual blades. The operation parameters of the turbine were recorded in parallel to the acoustic tests. In total more than 100 measurements were performed at wind speeds between 6 and 10 m/s. The array results reveal that besides a minor source at the rotor hub, practically all noise (emitted to the ground) is produced during the downward movement of the blades. This strongly asymmetric source pattern can be explained by convective amplification and trailing edge noise directivity. The blade noise is produced at the outer part of the blades (but not at the very tip), and the level scales with the fifth power of the local flow speed. Comparison of the noise from the individual blades shows that the tripped blade is significantly noisier than the other two. Narrowband analysis of the de-dopplerized blade noise spectra indicates that trailing edge bluntness noise is not important. All in all, the test results convincingly show that broadband trailing edge noise is the dominant noise source for this wind turbine.” S. Oerlemans, P. Sijtsma, B. Méndez López, Journal of Sound and Vibration, Volume 299, Issues 4–5, 6 February 2007, Pages 869–883, http://dx.doi.org/10.1016/j.jsv.2006.07.032.

Wind turbine underwater noise and marine mammals: implications of current knowledge and data needs – Madsen et al. (2006) “The demand for renewable energy has led to construction of offshore wind farms with high-power turbines, and many more wind farms are being planned for the shallow waters of the world’s marine habitats. The growth of offshore wind farms has raised concerns about their impact on the marine environment. Marine mammals use sound for foraging, orientation and communication and are therefore possibly susceptible to negative effects of man-made noise generated from constructing and operating large offshore wind turbines. This paper reviews the existing literature and assesses zones of impact from different noise-generating activities in conjunction with wind farms on 4 representative shallow-water species of marine mammals. Construction involves many types of activities that can generate high sound pressure levels, and pile-driving seems to be the noisiest of all. Both the literature and modeling show that pile-driving and other activities that generate intense impulses during construction are likely to disrupt the behavior of marine mammals at ranges of many kilometers, and that these activities have the potential to induce hearing impairment at close range. The reported noise levels from operating wind turbines are low, and are unlikely to impair hearing in marine mammals. The impact zones for marine mammals from operating wind turbines depend on the low-frequency hearing-abilities of the species in question, on sound-propagation conditions, and on the presence of other noise sources such as shipping. The noise impact on marine mammals is more severe during the construction of wind farms than during their operation.” P. T. Madsen, M. Wahlberg, J. Tougaard, K. Lucke, P. Tyack, Marine Ecology Progress Series, 309:279-295 (2006), doi:10.3354/meps309279. [FULL TEXT]

Infrasound Emission from Wind Turbines – Jakobsen (2005) “A critical survey of all known published measurement results of infrasound from wind turbines has been made. The survey indicates that wind turbines of contemporary design with an upwind rotor generate very faint infrasound with a level far below the threshold of perception even at a rather short distance. From considerations on propagation and transmission of infrasound it is concluded that infrasound from such upwind turbines can be neglected when evaluating the environment effects of wind turbines. Turbines with downwind rotors produce 10 – 30 dB higher infrasound levels, and these may exceed relevant assessment criteria for dwellings in the immediate neighbourhood. When longer distances are considered, neither downwind nor upwind turbines are capable of violating assessment criteria for infrasound. This paper considers whether other aspects of the noise than the infrasound can explain the indicated adverse public reactions to large downwind turbines.” Jørgen Jakobsen, Low Frequency Noise, Vibration and Active Control, Volume 24, Number 3 / September 2005, DOI: 10.1260/026309205775374451. [FULL TEXT]

Perception and annoyance due to wind turbine noise—a dose–response relationship – Pedersen & Waye (2004) “Installed global wind power increased by 26% during 2003, with U.S and Europe accounting for 90% of the cumulative capacity. Little is known about wind turbines’ impact on people living in their vicinity. The aims of this study were to evaluate the prevalence of annoyance due to wind turbine noise and to study dose–response relationships. Interrelationships between noise annoyance and sound characteristics, as well as the influence of subjective variables such as attitude and noise sensitivity, were also assessed. A cross-sectional study was performed in Sweden in 2000. Responses were obtained through questionnaires (n = 351; response rate 68.4%), and doses were calculated as A-weighted sound pressure levels for each respondent. A statistically significant dose–response relationship was found, showing higher proportion of people reporting perception and annoyance than expected from the present dose–response relationships for transportation noise. The unexpected high proportion of annoyance could be due to visual interference, influencing noise annoyance, as well as the presence of intrusive sound characteristics. The respondents’ attitude to the visual impact of wind turbines on the landscape scenery was found to influence noise annoyance.” Eja Pedersen and Kerstin Persson Waye, J. Acoust. Soc. Am. Volume 116, Issue 6, pp. 3460-3470, http://dx.doi.org/10.1121/1.1815091. [FULL TEXT]

Effects of the wind profile at night on wind turbine sound – van den Berg (2004) “Since the start of the operation of a 30 MW, 17 turbine wind park, residents living 500 m and more from the park have reacted strongly to the noise; residents up to 1900 m distance expressed annoyance. To assess actual sound immission, long term measurements (a total of over 400 night hours in 4 months) have been performed at 400 and 1500 m from the park. In the original sound assessment a fixed relation between wind speed at reference height (10 m) and hub height (98 m) had been used. However, measurements show that the wind speed at hub height at night is up to 2.6 times higher than expected, causing a higher rotational speed of the wind turbines and consequentially up to 15 dB higher sound levels, relative to the same reference wind speed in daytime. Moreover, especially at high rotational speeds the turbines produce a ‘thumping’, impulsive sound, increasing annoyance further. It is concluded that prediction of noise immission at night from (tall) wind turbines is underestimated when measurement data are used (implicitly) assuming a wind profile valid in daytime.” G.P. van den Berg, Journal of Sound and Vibration, Volume 277, Issues 4–5, 5 November 2004, Pages 955–970, http://dx.doi.org/10.1016/j.jsv.2003.09.050.

Psycho-acoustic characters of relevance for annoyance of wind turbine noise – Waye & Öhrström (2002) “The knowledge of annoyance and perception of wind turbine noise is limited, although some previous studies have found that the relationship between the equivalent noise level and annoyance was weak. The hypothesis for this study was that different sound characters in the noise not fully described by the equivalent noise level, are of importance for annoyance and noise perception. In total, 25 subjects were exposed to five different wind turbine noises at the level of 40 dBLAeq. Subjective ratings of annoyance, relative annoyance and for how long they were aware of the noises were carried out after 10 min exposures. This was followed by 3 min exposures where perception and annoyance of 14 psycho-acoustic descriptors were evaluated. The results showed that the rating of annoyance, relative annoyance and awareness was different between the wind turbine noises, although they had the same equivalent noise level. A psycho-acoustic profile was obtained for each noise, which subjectively described the most and the least annoying sound parameters. None of the psycho-acoustic parameters, sharpness, loudness, roughness, fluctuation strength or modulation could explain the differences in annoyance response.” K.Persson Waye, E. Öhrström, Journal of Sound and Vibration, Volume 250, Issue 1, 7 February 2002, Pages 65–73, http://dx.doi.org/10.1006/jsvi.2001.3905.

Aeroacoustics of large wind turbines – Hubbard & Shepherd (1991) “This paper reviews published information on aerodynamically generated noise from large horizontal axis wind turbines operated for electric power generation. Methods are presented for predicting both the discrete frequency rotational noise components and the broadband noise components, and results are compared with measurements. Refraction effects that result in the formation of high-frequency shadow zones in the upwind direction and channeling effects for the low frequencies in the downwind direction are illustrated. Special topics such as distributed source effects in prediction and the role of building dynamics in perception are also included. © 1991 Acoustical Society of America.” Harvey H. Hubbard and Kevin P. Shepherd, J. Acoust. Soc. Am. Volume 89, Issue 6, pp. 2495-2508 (1991), http://dx.doi.org/10.1121/1.401021.

Noise characteristics of large wind turbine generators – Hubbard et al. (1983) “Data on wind turbine noise taken from the large wind turbines, the Mod-OA, Mod-1, and Mod-2, are examined for guides to developing a predictive model for wind turbine noise. Data were taken on the pressure time histories, the narrowband spectra, the one-third octave band spectra, and the overall linear and A-weighted noise levels. A thumping noise recorded upstream from the Mod-1 was due to the encounter of the downwind turning blades with the tower wake. The upwind Mod-2 caused broadband noise with peaks at 800 Hz, caused by interactions of turbulent boundary layers with the blade trailing edges. Amplitude modulation of the overall pressure time history was associated with a periodic swishing noise. Some noises were machine specific; however, the low frequency loading was directed upwind and downwind from the rotors in all machines, while the broadband noise was nondirectional. The wind velocity gradient elongated the noise downwind and shortened it upwind. Wake acoustic measurements of two of the Mod-2 machines indicated that the wake does not affect the acoustic output of one Mod-2 downwind from the other. Finally, evidence was found for random phase adding of broadband noise five rotors downstream.” Hubbard, H H, Grosveld, F W, Shepherd, K P, Noise Control Engineering Journal (ISSN 0736-2501), vol. 21, July-Aug. 1983, p. 21-29.

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Papers on bird and bat mortality caused by wind power

Posted by Ari Jokimäki on November 9, 2011

This is a list of papers on bird and bat mortality caused by wind power. Also studies on wind power effects to other animals can be included. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

Weak relationship between risk assessment studies and recorded mortality in wind farms – Ferrer et al. (2011) “Wind farms generate little or no pollution. However, one of their main adverse impacts is bird mortality through collisions with turbine rotors. Environmental impact assessment (EIA) studies have been based on observations of birds before the construction of wind farms. We analysed data from 53 EIAs in relation to the actual recorded bird mortalities at 20 fully installed wind farms to determine whether this method is accurate in predicting the risk of new wind farm installations. Bird data from EIAs were compared with bird collisions per turbine and year at functional post-constructed wind farms to identify any relationship between pre- and post-construction studies. Significant differences in birds recorded flying among the 53 proposed wind farms were found by the EIAs. Similar results were obtained when only griffon vultures Gyps fulvus and other raptors were considered. There were significant differences in indexes, including the relative index of breeding birds close to proposed locations, among the 53 proposed wind farm sites. The collision rate of birds with turbines was one of the highest ever recorded for raptors, and the griffon vulture was the most frequently killed species. Bird mortality varied among the 20 constructed wind farms. No relationship between variables predicting risk from EIAs and actual recorded mortality was found. A weak relationship was found between griffon vulture and kestrel Falco sp. mortality and the numbers of these two species crossing the area. Synthesis and applications. There was no clear relationship between predicted risk and the actual recorded bird mortality at wind farms. Risk assessment studies incorrectly assumed a linear relationship between frequency of observed birds and fatalities. Nevertheless, it is known that bird mortality in wind farms is related to physical characteristics around individual wind turbines. However, EIAs are usually conducted at the scale of the entire wind farm. The correlation between predicted mortality and actual mortality must be improved in future risk assessment studies by changing the scale of these studies to focus on the locations of proposed individual wind turbine sites and working on a species specific level.” Miguel Ferrer, Manuela de Lucas, Guyonne F. E. Janss, Eva Casado, Antonio R. Muñoz, Marc J. Bechard, Cecilia P. Calabuig, Journal of Applied Ecology, DOI: 10.1111/j.1365-2664.2011.02054.x. [Full text]

Novel Scavenger Removal Trials Increase Wind Turbine—Caused Avian Fatality Estimates – Smallwood et al. (2010) “For comparing impacts of bird and bat collisions with wind turbines, investigators estimate fatalities/megawatt (MW) of rated capacity/year, based on periodic carcass searches and trials used to estimate carcasses not found due to scavenger removal and searcher error. However, scavenger trials typically place ≥10 carcasses at once within small areas already supplying scavengers with carcasses deposited by wind turbines, so scavengers may be unable to process and remove all placed carcasses. To avoid scavenger swamping, which might bias fatality estimates low, we placed only 1–5 bird carcasses at a time amongst 52 wind turbines in our 249.7-ha study area, each carcass monitored by a motion-activated camera. Scavengers removed 50 of 63 carcasses, averaging 4.45 days to the first scavenging event. By 15 days, which corresponded with most of our search intervals, scavengers removed 0% and 67% of large-bodied raptors placed in winter and summer, respectively, and 15% and 71% of small birds placed in winter and summer, respectively. By 15 days, scavengers removed 42% of large raptors as compared to 15% removed in conventional trials, and scavengers removed 62% of small birds as compared to 52% removed in conventional trials. Based on our methodology, we estimated mean annual fatalities caused by 21.9 MW of wind turbines in Vasco Caves Regional Preserve (within Altamont Pass Wind Resource Area, California, USA) were 13 red-tailed hawks (Buteo jamaicensis), 12 barn owls (Tyto alba), 18 burrowing owls (Athene cunicularia), 48 total raptors, and 99 total birds. Compared to fatality rates estimated from conventional scavenger trials, our estimates were nearly 3 times higher for red-tailed hawk and barn owl, 68% higher for all raptors, and 67% higher for all birds. We also found that deaths/gigawatt-hour of power generation declined quickly with increasing capacity factor among wind turbines, indicating collision hazard increased with greater intermittency in turbine operations. Fatality monitoring at wind turbines might improve by using scavenger removal trials free of scavenger swamping and by relating fatality rates to power output data in addition to rated capacity (i.e., turbine size). The resulting greater precision in mortality estimates will assist wildlife managers to assess wind farm impacts and to more accurately measure the effects of mitigation measures implemented to lessen those impacts.” K. Shawn Smallwood, Douglas A. Bell, Sara A. Snyder, Joseph E. Didonato, The Journal of Wildlife Management, Volume 74, Issue 5, pages 1089–1096, July 2010, DOI: 10.2193/2009-266.

Influence of Behavior on Bird Mortality in Wind Energy Developments – Smallwood et al. (2009) “As wind power generation is rapidly expanding worldwide, there is a need to understand whether and how preconstruction surveys can be used to predict impacts and to place turbines to minimize impacts to birds. Wind turbines in the 165-km2 Altamont Pass Wind Resource Area (APWRA), California, USA, cause thousands of bird fatalities annually, including hundreds of raptors. To test whether avian fatality rates related to rates of utilization and specific behaviors within the APWRA, from March 1998 to April 2000 we performed 1,959 30-minute behavior observation sessions (360° visual scans using binoculars) among 28 nonoverlapping plots varying from 23 ha to 165 ha in area and including 10–67 turbines per plot, totaling 1,165 turbines. Activity levels were highly seasonal and species specific. Only 1% of perch time was on towers of operating turbines, but 22% was on towers of turbines broken, missing, or not operating. Of those species that most often flew through the rotor zone, fatality rates were high for some (e.g., 0.357 deaths/megawatt of rated capacity [MW]/yr for red-tailed hawk [Buteo jamaicensis] and 0.522 deaths/MW/yr for American kestrel [Falco sparverius]) and low for others (e.g., 0.060 deaths/MW/yr for common raven [Corvus corax] and 0.012 deaths/MW/yr for turkey vulture [Cathartes aura]), indicating specific behaviors or visual acuity differentiated these species by susceptibility to collision. Fatality rates did not correlate with utilization rates measured among wind turbine rows or plots for any species except burrowing owl (Athene cunicularia) and mallard (Anas platyrhynchos). However, mean monthly fatality rates of red-tailed hawks increased with mean monthly utilization rates (r2 = 0.67) and especially with mean monthly flights through turbine rows (r2 = 0.92). Fatality rates increased linearly with rates of utilization (r2 = 0.99) and flights near rotor zones (r2 = 1.00) for large raptor species and with rates of perching (r2 = 0.13) and close flights (r2 = 0.77) for small non-raptor species. Fatalities could be minimized or reduced by shutting down turbines during ≥1 season or in very strong winds or by leaving sufficiently large areas within a wind farm free of wind turbines to enable safer foraging and travel by birds.” K. Shawn Smallwood, Lourdes Rugge, Michael L. Morrison, The Journal of Wildlife Management, Volume 73, Issue 7, pages 1082–1098, September 2009, DOI: 10.2193/2008-555.

Collision fatality of raptors in wind farms does not depend on raptor abundance – De Lucas et al. (2008) “The number of wind farms is increasing worldwide. Despite their purported environmental benefits, wind energy developments are not without potential adverse impacts on the environment, and the current pace and scale of development proposals, combined with a poor understanding of their impacts, is a cause for concern. Avian mortality through collision with moving rotor blades is one of the main adverse impacts of wind farms, yet long-term studies are rare. We analyse bird fatalities in relation to bird abundance, and test several factors which have been hypothesized to be associated with bird mortality. Bird abundance was compared with collision fatality records to identify species-specific death risk. Failure time analysis incorporated censored mortality data in which the time of event occurrence (collision) was not known. The analysis was used to test null hypotheses of homogeneity in avian mortality distribution according to several factors. There was no clear relationship between species mortality and species abundance, although all large-bird collision victims were raptors and griffon vulture Gyps fulvus was most frequently killed. Bird mortality and bird abundance varied markedly among seasons, but mortality was not highest in the season with highest bird abundance. Mortality rates of griffon vultures did not differ significantly between years. Bird collision probability depended on species, turbine height (taller = more victims) and elevation above sea level (higher = more victims), implicating species-specific and topographic factors in collision mortality. There was no evidence of an association between collision probability and turbine type or the position of a turbine in a row. Synthesis and applications. Bird abundance and bird mortality through collision with wind turbines were not closely related; this result challenges a frequent assumption of wind-farm assessment studies. Griffon vulture was the most frequently killed species, and species-specific flight behaviour was implicated. Vultures collided more often when uplift wind conditions were poor, such as on gentle slopes, when thermals were weak, and when turbines were taller at higher elevations. New wind installations and/or repowering of older wind farms with griffon vulture populations nearby, should avoid turbines on the top of hills with gentle slopes.” Manuela De Lucas, Guyonne F. E. Janss, D. P. Whitfield, Miguel Ferrer, Journal of Applied Ecology, Volume 45, Issue 6, pages 1695–1703, December 2008, DOI: 10.1111/j.1365-2664.2008.01549.x. [Full text]

Collision Effects of Wind-power Generators and Other Obstacles on Birds – Drewitt & Langston (2008) “There is extensive literature on avian mortality due to collision with man-made structures, including wind turbines, communication masts, tall buildings and windows, power lines, and fences. Many studies describe the consequences of bird-strike rather than address the causes, and there is little data based on long-term, standardized, and systematic assessments. Despite these limitations, it is apparent that bird-strike is a significant cause of mortality. It is therefore important to understand the effects of this mortality on bird populations. The factors which determine avian collision risk are described, including location, structural attributes, such as height and the use of lighting, weather conditions, and bird morphology and behavior. The results of incidental and more systematic observations of bird-strike due to a range of structures are presented and the implications of collision mortality for bird populations, particularly those of scarce and threatened species susceptible to collisions, are discussed. Existing measures for reducing collision mortality are described, both generally and specifically for each type of structure. It is concluded that, in some circumstances, collision mortality can adversely affect bird populations, and that greater effort is needed to derive accurate estimates of mortality levels locally, regionally, and nationally to better assess impacts on avian populations. Priority areas for future work are suggested, including further development of remote technology to monitor collisions, research into the causes of bird-strike, and the design of new, effective mitigation measures.” Allan L. Drewitt, Rowena H.W. Langston, Annals of the New York Academy of Sciences, Volume 1134, Issue 1, pages 233–266, June 2008, DOI: 10.1196/annals.1439.015. [Full text]

Barotrauma is a significant cause of bat fatalities at wind turbines – Baerwald et al. (2008) “Bird fatalities at some wind energy facilities around the world have been documented for decades, but the issue of bat fatalities at such facilities — primarily involving migratory species during autumn migration — has been raised relatively recently [1] and [2] . Given that echolocating bats detect moving objects better than stationary ones [3], their relatively high fatality rate is perplexing, and numerous explanations have been proposed [1]. The decompression hypothesis proposes that bats are killed by barotrauma caused by rapid air-pressure reduction near moving turbine blades [1] , [4] and [5] . Barotrauma involves tissue damage to air-containing structures caused by rapid or excessive pressure change; pulmonary barotrauma is lung damage due to expansion of air in the lungs that is not accommodated by exhalation. We report here the first evidence that barotrauma is the cause of death in a high proportion of bats found at wind energy facilities. We found that 90% of bat fatalities involved internal haemorrhaging consistent with barotrauma, and that direct contact with turbine blades only accounted for about half of the fatalities. Air pressure change at turbine blades is an undetectable hazard and helps explain high bat fatality rates. We suggest that one reason why there are fewer bird than bat fatalities is that the unique respiratory anatomy of birds is less susceptible to barotrauma than that of mammals.” Erin F. Baerwald, Genevieve H. D’Amours, Brandon J. Klug, Robert M.R. Barclay, Current Biology, Volume 18, Issue 16, 26 August 2008, Pages R695-R696, doi:10.1016/j.cub.2008.06.029. [Full text]

Bird Mortality in the Altamont Pass Wind Resource Area, California – Smallwood & Thelander (2008) “The 165-km2 Altamont Pass Wind Resource Area (APWRA) in west-central California includes 5,400 wind turbines, each rated to generate between 40 kW and 400 kW of electric power, or 580 MW total. Many birds residing or passing through the area are killed by collisions with these wind turbines. We searched for bird carcasses within 50 m of 4,074 wind turbines for periods ranging from 6 months to 4.5 years. Using mortality estimates adjusted for searcher detection and scavenger removal rates, we estimated the annual wind turbine–caused bird fatalities to number 67 (80% CI = 25–109) golden eagles (Aquila chrysaetos), 188 (80% CI = 116–259) red-tailed hawks (Buteo jamaicensis), 348 (80% CI = −49 to 749) American kestrels (Falco sparverius), 440 (80% CI = −133 to 1,013) burrowing owls (Athene cunicularia hypugaea), 1,127 (80% CI = −23 to 2,277) raptors, and 2,710 (80% CI = −6,100 to 11,520) birds. Adjusted mortality estimates were most sensitive to scavenger removal rate, which relates to the amount of time between fatality searches. New on-site studies of scavenger removal rates might warrant revising mortality estimates for some small-bodied bird species, although we cannot predict how the mortality estimates would change. Given the magnitude of our mortality estimates, regulatory agencies and the public should decide whether to enforce laws intended to protect species killed by APWRA wind turbines, and given the imprecision of our estimates, directed research is needed of sources of error and bias for use in studies of bird collisions wherever wind farms are developed. Precision of mortality estimates could be improved by deploying technology to remotely detect collisions and by making wind turbine power output data available to researchers so that the number of fatalities can be related directly to the actual power output of the wind turbine since the last fatality search.” K. Shawn Smallwood, Carl Thelander, The Journal of Wildlife Management, Volume 72, Issue 1, pages 215–223, January 2008, DOI: 10.2193/2007-032.

Patterns of Bat Fatalities at Wind Energy Facilities in North America – Arnett et al. (2008) “Wind has become one of the fastest growing sources of renewable energy worldwide, but widespread and often extensive fatalities of bats have increased concern regarding the impacts of wind energy development on bats and other wildlife. We synthesized available information on patterns of bat fatalities from a review of 21 postconstruction fatality studies conducted at 19 facilities in 5 United States regions and one Canadian province. Dominance of migratory, foliage- and tree-roosting lasiurine species (e.g., hoary bat [Lasiurus cinereus]) killed by turbines was consistent among studies. Bat fatalities, although highly variable and periodic, consistently peaked in late summer and fall, coinciding with migration of lasiurines and other species. A notable exception was documented fatalities of pregnant female Brazilian freetailed bats (Tadarida brasiliensis) in May and June at a facility in Oklahoma, USA, and female silver-haired bats (Lasionycteris noctivagans) during spring in Tennessee, USA, and Alberta, Canada. Most studies reported that fatalities were distributed randomly across turbines at a site, although the highest number of fatalities was often found near the end of turbine strings. Two studies conducted simultaneously in the same region documented similar timing of fatalities between sites, which suggests broader patterns of collisions dictated by weather, prey abundance, or other factors. None of the studies found differences in bat fatalities between turbines equipped with lighting required by the Federal Aviation Administration and turbines that were unlit. All studies that addressed relationships between bat fatalities and weather patterns found that most bats were killed on nights with low wind speed (<6 m/sec) and that fatalities increased immediately before and after passage of storm fronts. Weather patterns may be predictors of bat activity and fatality; thus, mitigation efforts that focus on these high-risk periods could reduce bat fatality substantially. We caution that estimates of bat fatality are conditioned by length of study and search interval and that they are biased in relation to how searcher efficiency, scavenger removal, and habitat differences were or were not accounted for. Our review will assist managers, biologists, and decision-makers with understanding unifying and unique patterns of bat fatality, biases, and limitations of existing efforts, and it will aid in designing future research needed to develop mitigation strategies for minimizing or eliminating bat fatality at wind facilities.” Edward B. Arnett, W. Kent Brown, Wallace P. Erickson, Jenny K. Fiedler, Brenda L. Hamilton, Travis H. Henry, Aaftab Jain, Gregory D. Johnson, Jessica Kerns, Rolf R. Koford, Charles P. Nicholson, Timothy J. O’Connell, Martin D. Piorkowski, Roger D. Tankersley JR., The Journal of Wildlife Management, Volume 72, Issue 1, pages 61–78, January 2008, DOI: 10.2193/2007-221.

Assessing Impacts of Wind-Energy Development on Nocturnally Active Birds and Bats: A Guidance Document – Kunz et al. (2007) “Our purpose is to provide researchers, consultants, decision-makers, and other stakeholders with guidance to methods and metrics for investigating nocturnally active birds and bats in relation to utility-scale wind-energy development. The primary objectives of such studies are to 1) assess potential impacts on resident and migratory species, 2) quantify fatality rates on resident and migratory populations, 3) determine the causes of bird and bat fatalities, and 4) develop, assess, and implement methods for reducing risks to bird and bat populations and their habitats. We describe methods and tools and their uses, discuss limitations, assumptions, and data interpretation, present case studies and examples, and offer suggestions for improving studies on nocturnally active birds and bats in relation to wind-energy development. We suggest best practices for research and monitoring studies using selected methods and metrics, but this is not intended as cookbook. We caution that each proposed and executed study will be different, and that decisions about which methods and metrics to use will depend upon several considerations, including study objectives, expected and realized risks to bird and bat populations, as well as budgetary and logistical considerations. Developed to complement and extend the existing National Wind Coordinating Committee document “Methods and Metrics for Assessing Impacts of Wind Energy Facilities on Wildlife” (Anderson et al. 1999), we provide information that stakeholders can use to aid in evaluating potential and actual impacts of wind power development on nocturnally active birds and bats. We hope that decision-makers will find these guidelines helpful as they assemble information needed to support the permitting process, and that the public will use this guidance document as they participate in the permitting processes. We further hope that the wind industry will find valuable guidance from this document when 1) complying with data requirements as a part of the permitting process, 2) evaluating sites for potential development, 3) assessing impacts of operational wind-energy facilities, and 4) mitigating local and cumulative impacts on nocturnally active birds and bats.” Thomas H. Kunz, Edward B. Arnett, Brian M. Cooper, Wallace P. Erickson, Ronald P. Larkin, Todd Mabee, Michael L. Morrison, M. Dale Strickland, Joseph M. Szewczak, The Journal of Wildlife Management, Volume 71, Issue 8, pages 2449–2486, November 2007, DOI: 10.2193/2007-270. [Full text]

Ecological impacts of wind energy development on bats: questions, research needs, and hypotheses – Kunz et al. (2007) “At a time of growing concern over the rising costs and long-term environmental impacts of the use of fossil fuels and nuclear energy, wind energy has become an increasingly important sector of the electrical power industry, largely because it has been promoted as being emission-free and is supported by government subsidies and tax credits. However, large numbers of bats are killed at utility-scale wind energy facilities, especially along forested ridgetops in the eastern United States. These fatalities raise important concerns about cumulative impacts of proposed wind energy development on bat populations. This paper summarizes evidence of bat fatalities at wind energy facilities in the US, makes projections of cumulative fatalities of bats in the Mid-Atlantic Highlands, identifies research needs, and proposes hypotheses to better inform researchers, developers, decision makers, and other stakeholders, and to help minimize adverse effects of wind energy development.” Thomas H. Kunz, Edward B. Arnett, Wallace P. Erickson, Alexander R. Hoar, Gregory D. Johnson, Ronald P. Larkin, M Dale Strickland, Robert W. Thresher, and Merlin D. Tuttle, 2007, Frontiers in Ecology and the Environment 5: 315–324, doi:10.1890/1540-9295(2007)5[315:EIOWED]2.0.CO;2. [Full text]

Estimating Wind Turbine-Caused Bird Mortality – Smallwood (2007) “Mortality estimates are needed of birds and bats killed by wind turbines because wind power generation is rapidly expanding worldwide. A mortality estimate is based on the number of fatalities assumed caused by wind turbines and found during periodic searches, plus the estimated number not found. The 2 most commonly used estimators adjust mortality estimates by rates of searcher detection and scavenger removal of carcasses. However, searcher detection trials can be biased by the species used in the trial, the number volitionally placed for a given fatality search, and the disposition of the carcass on the ground. Scavenger removal trials can be biased by the metric representing removal rate, the number of carcasses placed at once, the duration of the trial, species used, whether carcasses were frozen, whether carcasses included injuries consistent with wind turbine collisions, season, distance from the wind turbines, and general location. I summarized searcher detection rates among reported trials, and I developed models to predict the proportion of carcasses remaining since the last fatality search. The summaries I present can be used to adjust previous and future estimates of mortality to improve comparability. I also identify research directions to better understand these and other adjustments needed to compare mortality estimates among wind farms.” K. Shawn Smallwood, The Journal of Wildlife Management, Volume 71, Issue 8, pages 2781–2791, November 2007, DOI: 10.2193/2007-006.

Migration of bats past a remote island offers clues toward the problem of bat fatalities at wind turbines – Cryan & Brown (2007) “Wind energy is rapidly becoming a viable source of alternative energy, but wind turbines are killing bats in many areas of North America. Most of the bats killed by turbines thus far have been migratory species that roost in trees throughout the year, and the highest fatality events appear to coincide with autumn migration. Hoary bats (Lasiurus cinereus) are highly migratory and one of the most frequently killed species at wind turbines. We analyzed a long-term data set to investigate how weather and moonlight influenced the occurrence of hoary bats at an island stopover point along their migration route. We then related our results to the problem of bat fatalities at wind turbines. We found that relatively low wind speeds, low moon illumination, and relatively high degrees of cloud cover were important predictors of bat arrivals and departures, and that low barometric pressure was an additional variable that helped predict arrivals. Slight differences in the conditions under which bats arrived and departed from the island suggest that hoary bats may be more likely to arrive on the island with passing storm fronts in autumn. These results also indicate that fatalities of hoary bats at wind turbines may be predictable events, that the species may be drawn to prominent landmarks that they see during migration, and that they regularly migrate over the ocean. Additional observations from this and other studies suggest that the problem of bat fatalities at wind turbines may be associated with flocking and autumn mating behaviors.” Paul M. Cryan, Adam C. Brown, Biological Conservation, Volume 139, Issues 1-2, September 2007, Pages 1-11, doi:10.1016/j.biocon.2007.05.019. [Full text]

Variation in bat and bird fatalities at wind energy facilities: assessing the effects of rotor size and tower height – Barclay et al. (2007) “Wind energy is a rapidly growing sector of the alternative energy industry in North America, and larger, more productive turbines are being installed. However, there are concerns regarding bird and bat fatalities at wind turbines. To assess the influence of turbine size on bird and bat fatalities, we analyzed data from North American wind energy facilities. Diameter of the turbine rotor did not influence the rate of bird or bat fatality. The height of the turbine tower had no effect on bird fatalities per turbine, but bat fatalities increased exponentially with tower height. This suggests that migrating bats fly at lower altitudes than nocturnally migrating birds and that newer, larger turbines are reaching that airspace. Minimizing tower height may help minimize bat fatalities. In addition, while replacing older, smaller turbines with fewer larger ones may reduce bird fatalities per megawatt, it may result in increased numbers of bat fatalities.” Robert M.R. Barclay, E.F. Baerwald, J.C. Gruver, Canadian Journal of Zoology, 2007, 85:(3) 381-387, 10.1139/Z07-011. [Full text]

Assessing the impacts of wind farms on birds – Drewitt & Langston (2006) “The potential effects of the proposed increase in wind energy developments on birds are explored using information from studies of existing wind farms. Evidence of the four main effects, collision, displacement due to disturbance, barrier effects and habitat loss, is presented and discussed. The consequences of such effects may be direct mortality or more subtle changes to condition and breeding success. The requirements for assessing the impact of future developments are summarized, including relevant environmental legislation and appropriate methods for undertaking baseline surveys and post-construction monitoring, with particular emphasis on the rapidly developing area of offshore wind farm assessments. Mitigation measures which have the potential to minimize impacts are also summarized. Finally, recent developments in the monitoring and research of wind energy impacts on birds are outlined and some areas for future work are described.” Allan L. Drewitt, Rowena H. W. Langston, Ibis, Special Issue: Wind, Fire and Water: Renewable Energy and Birds, Volume 148, Issue Supplement s1, pages 29–42, March 2006, DOI: 10.1111/j.1474-919X.2006.00516.x. [Full text]

The effect of avoidance rates on bird mortality predictions made by wind turbine collision risk models – Chamberlain et al. (2006) No abstract. Dan E. Chamberlain, Mark R. Rehfisch, Antony D. Fox, Mark. Desholm, Sarah J. Anthony, Ibis, Special Issue: Wind, Fire and Water: Renewable Energy and Birds, Volume 148, Issue Supplement s1, pages 198–202, March 2006, DOI: 10.1111/j.1474-919X.2006.00507.x. [Full text]

See also other papers in Ibis special issue.

Behavioural and environmental correlates of soaring-bird mortality at on-shore wind turbines – Barrios & Rodríguez (2004) “Wind power plants represent a risk of bird mortality, but the effects are still poorly quantified. We measured bird mortality, analysed the factors that led birds to fly close to turbines, and proposed mitigation measures at two wind farms installed in the Straits of Gibraltar, one of the most important migration bottlenecks between Europe and Africa. Bird corpses were surveyed along turbine lines and an associated power line to estimate mortality rates. The behaviour of birds observed within 250 m of turbines was also recorded as a putative indicator of risk. The effects of location, weather and flight behaviour on risk situations (passes within 5 m of turbines) were analysed using generalized linear modelling (GLM). Mortality caused by turbines was higher than that caused by the power line. Losses involved mainly resident species, mostly griffon vultures Gyps fulvus (0·15 individuals turbine−1 year−1) and common kestrels Falco tinnunculus (0·19 individuals turbine−1 year−1). Mortalities were not associated with either structural attributes of wind farms or visibility. Vulture collisions occurred in autumn–winter and were aggregated at two turbine lines where risks of collisions were greatest. The absence of thermals in winter forced vultures to use slopes for lift, the most likely mechanism influencing both their exposure to turbines and mortality. Kestrel deaths occurred during the annual peak of abundance in summer. Carcasses were concentrated in the open habitats around a single wind farm and risk may have resulted from hunting habitat preferences. Synthesis and applications. We conclude that bird vulnerability and mortality at wind power facilities reflect a combination of site-specific (wind–relief interaction), species-specific and seasonal factors. Despite the large number of migrating birds in the study area, most follow routes that are displaced from the facilities. Consequently, only a small fraction of birds on migratory flights was actually exposed to turbines. New wind installations must be preceded by detailed behavioural observation of soaring birds as well as careful mapping of migration routes.” Luis Barrios, Alejandro Rodríguez, Journal of Applied Ecology, Volume 41, Issue 1, pages 72–81, February 2004, DOI: 10.1111/j.1365-2664.2004.00876.x. [Full text]

The effects of a wind farm on birds in a migration point: the Strait of Gibraltar – de Lucas et al. (2004) “The interaction between birds and wind turbines is an important factor to consider when a wind farm is constructed. A wind farm and two control areas were studied in Tarifa (Andalusia Province, southern Spain, 30STF590000–30STE610950). Variables were studied along linear transects in each area and observations of flight were also recorded from fixed points in the wind farm. The main purpose of our research was to determine the impact and the degree of flight behavioural change in birds flights resulting from a wind farm. Soaring birds can detect the presence of the turbines because they change their flight direction when they fly near the turbines and their abundance did not seem to be affected. This is also supported by the low amount of dead birds we found in the whole study period in the wind farm area. More studies will be necessary after and before the construction of wind farms to assess changes in passerine populations. Windfarms do not appear to be more detrimental to birds than other man-made structures.” Manuela de Lucas, Guyonne F.E. Janss and Miguel Ferrer, Biodiversity and Conservation, Volume 13, Number 2, 395-407, DOI: 10.1023/B:BIOC.0000006507.22024.93. [Full text]

Mortality of Bats at a Large-scale Wind Power Development at Buffalo Ridge, Minnesota – Johnson et al. (2003) “In 1994 a major wind power development project was initiated in southwest Minnesota that may eventually produce 425 megawatts (MW) of electricity. The wind plant currently consists of 3 phases that total 354 turbines capable of generating 236 MW. During a study conducted from 1996–1999 to assess effects of wind power development on wildlife, 184 bat collision fatalities were documented within the wind plant. Hoary bats (Lasiurus cinereus) and eastern red bats (L. borealis) comprised most of the fatalities. After correcting bat fatality estimates for searcher efficiency and scavenger removal rates, we estimated that the number of bat fatalities per turbine ranged from 0.07 per y at the Phase 1 wind plant to 2.04 per y at the Phase 3 wind plant. The timing of mortalities, and other factors, suggest that most mortality involves migrant rather than resident breeding bats.” Gregory D. Johnson, Wallace P. Erickson, M. Dale Strickland, Maria F. Shepherd, Douglas A. Shepherd, and Sharon A. Sarappo, The American Midland Naturalist 150(2):332-342. 2003, doi: 10.1674/0003-0031(2003)150[0332:MOBAAL]2.0.CO;2. [Full text]

Collision Mortality of Local and Migrant Birds at a Large-Scale Wind-Power Development on Buffalo Ridge, Minnesota – Johnson et al. (2002) “In 1994 Xcel Energy initiated a wind-power development project in southwestern Minnesota that will eventually produce 425 megawatts (MW) of electricity. During our study the wind farm consisted of 3 phases of development totaling 354 turbines capable of generating 236 MW, depending on wind speed. We assessed effects of the wind farm on birds from 1996 to 1999, with 55 documented collision fatalities. Recovered carcasses included 42 passerines, 5 waterbirds, 3 ducks, 3 upland game birds, 1 raptor, and 1 shorebird. Most fatalities (71%) were likely migrants through the area, 20% were species that likely were breeding in the study area, and 9% were permanent residents. Wind farm-related mortality was estimated by extrapolating the number of carcasses found at a sample of the turbines and adjusting for scavenger removal and searcher efficiency rates. We estimated total annual mortality at 72 (90% Cl = 36-108) in the Phase 1 wind farm, 324 (90% Cl = 175-473) in the Phase 2 wind farm, and 613 (90% Cl = 132-1093) in the Phase 3 wind farm. The Phase 3 wind-farm estimate was based on 1 year of data and was largely influenced by a single mortality event involving 14 passerines at 2 adjacent turbines during 1 night. Radar data indicated that approximately 3.5 million birds migrate over the wind farm each year; however, the proportion of birds flying at heights susceptible to turbine collisions is not known. Wind-power development will likely contribute to cumulative collision mortality of birds in the United States.” Gregory D. Johnson, Wallace P. Erickson, M. Dale Strickland, Maria F. Shepherd, Douglas A. Shepherd and Sharon A. Sarappo, Wildlife Society Bulletin, Vol. 30, No. 3 (Autumn, 2002), pp. 879-887.

Bird Mortality Associated with Wind Turbines at the Buffalo Ridge Wind Resource Area, Minnesota – Osborn et al. (2000) “Recent technological advances have made wind power a viable source of alternative energy production and the number of windplant facilities has increased in the United States. Construction was completed on a 73 turbine, 25 megawatt windplant on Buffalo Ridge near Lake Benton, Minnesota in Spring 1994. The number of birds killed at existing windplants in California caused concern about the potential impacts of the Buffalo Ridge facility on the avian community. From April 1994 through Dec. 1995 we searched the Buffalo Ridge windplant site for dead birds. Additionally, we evaluated search efficiency, predator scavenging rates and rate of carcass decomposition. During 20 mo of monitoring we found 12 dead birds. Collisions with wind turbines were suspected for 8 of the 12 birds. During observer efficiency trials searchers found 78.8% of carcasses. Scavengers removed 39.5% of carcasses during scavenging trials. All carcasses remained recognizable during 7 d decomposition trials. After correction for biases we estimated that approximately 36 ± 12 birds (<1 dead bird per turbine) were killed at the Buffalo Ridge windplant in 1 y. Although windplants do not appear to be more detrimental to birds than other man-made structures, proper facility siting is an important first consideration in order to avoid unnecessary fatalities.” Robert G. Osborn, Kenneth F. Higgins, Robert E. Usgaard, Charles D. Dieter, and Regg D. Neiger, The American Midland Naturalist 143(1):41-52. 2000, doi: 10.1674/0003-0031(2000)143[0041:BMAWWT]2.0.CO;2. [Full text]

Effects of Wind Turbines on Upland Nesting Birds in Conservation Reserve Program Grasslands – Leddy et al. (1999) “Grassland passerines were surveyed during summer 1995 on the Buffalo Ridge Wind Resource Area in southwestern Minnesota to determine the relative influence of wind turbines on overall densities of upland nesting birds in Conservation Reserve Program (CRP) grasslands. Birds were surveyed along 40 m fixed width transects that were placed along wind turbine strings within three CRP fields and in three CRP fields without turbines. Conservation Reserve Program grasslands without turbines and areas located 180 m from turbines supported higher densities (261.0-312.5 males/100 ha) of grassland birds than areas within 80 m of turbines (58.2-128.0 males/100 ha). Human disturbance, turbine noise, and physical movements of turbines during operation may have distrurbed nesting birds. We recommend that wind turbines be placed within cropland habitats that support lower densities of grassland passerines than those found in CRP grasslands.” Krecia L. Leddy, Kenneth F. Higgins and David E. Naugle, The Wilson Bulletin, Vol. 111, No. 1 (Mar., 1999), pp. 100-104.

Bird Flight Characteristics Near Wind Turbines in Minnesota – Osborn et al. (1998) “During 1994–1995, we saw 70 species of birds on the Buffalo Ridge Wind Resource Area. In both years bird abundance peaked in spring. Red-winged blackbirds (Agelaius phoeniceus), mallards (Anas platyrhynchos), common grackles (Quiscalus quiscula), and barn swallows (Hirundo rustica) were the species most commonly seen. Most birds (82–84%) flew above or below the height range of wind turbine blades (22–55 m). The Buffalo Ridge Wind Resource Area poses little threat to resident or migrating birds at its current operating level.” Robert G. Osborn, Charles D. Dieter, Kenneth F. Higgins, and Robert E. Usgaard, The American Midland Naturalist 139(1):29-38. 1998, doi: 10.1674/0003-0031(1998)139[0029:BFCNWT]2.0.CO;2. [Full text]

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Papers on health effects of increased CO2

Posted by Ari Jokimäki on November 4, 2011

This is a list of papers dealing with different aspects of the health effects of increased carbon dioxide. The list contains subsections for general studies, increasing atmospheric CO2 and allergies, and extreme carbon dioxide events. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (April 11, 2013): New section for atmospheric carbon dioxide and allergies added including 10 papers.
UPDATE (November 9, 2011): Robertson (2006) added.

General studies

High carbon dioxide concentrations in the classroom: the need for research on the effects of children’s exposure to poor indoor air quality at school – Miller et al. (2010) “Air quality and its effect on health have received recent attention from the House of Commons Environmental Audit Committee. 1 While outdoor air pollution is clearly important and contributes to indoor air quality, indoor air pollution sources and the time spent in indoor environments are key to understanding exposure.” Janice Miller, Sean Semple, Stephen Turner, Occup Environ Med 2010;67:799 doi:10.1136/oem.2010.057471.

Occupational hazards of carbon dioxide exposure – Scott et al. (2009) “This paper is an overview of the occupational hazards that result from exposure to carbon dioxide. It details the main uses, characteristics, and problems that have been identified when carbon dioxide is utilized in various working environments. Carbon dioxide is always a danger when present in enclosed spaces at elevated concentrations. Situations resulting from acute and chronic exposures involving the gaseous and dry ice forms of carbon dioxide are discussed in detail. Current rationale concerning exposure limits and monitoring recommendations are highlighted.” Jonathan L. Scott, David G. Kraemer, Randal J. Keller, Journal of Chemical Health and Safety, Volume 16, Issue 2, March-April 2009, Pages 18-22, doi:10.1016/j.jchas.2008.06.003.

Effects of carbon dioxide inhalation on psychomotor and mental performance during exercise and recovery – Vercruyssen et al. (2007) “On separate days, 6 highly trained participants performed psychomotor tests while breathing for 60 min 3 carbon dioxide (CO(2)) mixtures (room air, 3% CO(2), or 4% CO(2)) prior to, between, and following two 15-min treadmill exercise bouts (70% VO(2)(max)). Each individual was extensively practiced (at least 4 days) before testing began, and both gas conditions and order of tasks were counterbalanced. Results showed physiological reactions and work-related psychomotor effects, but no effects of gas concentration on addition, multiplication, grammatical reasoning, or dynamic postural balance. These findings help define behavioral toxicity levels and support a re-evaluation of existing standards for the maximum allowable concentrations (also emergency and continuous exposure guidance levels) of CO(2). This research explored the selection of psychometric instruments of sufficient sensitivity and reliability to detect subtle changes in performance caused by exposure to low levels of environmental stress, in this case differential levels of CO(2) in the inspired air.” Vercruyssen M, Kamon E, Hancock PA., Int J Occup Saf Ergon. 2007;13(1):15-27. [Full text]

Health effects of increase in concentration of carbon dioxide in the atmosphere – Robertson (2006) “The toxic effects, to humans and other mammals, of concentrations of carbon dioxide in the atmosphere which are below the safe working level but above the present level are described. The likely physiological effects of the predicted increase in concentration of carbon dioxide in the atmosphere over the next 50 years are detailed.” A quote from the article: “At a carbon dioxide concentration of 600 ppm in an indoor atmosphere, the occupants become aware of deterioration in the atmosphere. At and above this level, some occupants began to display one or more of the classic symptoms of carbon dioxide poisoning, e.g. difficulty in breathing, rapid pulse rate, headache, hearing loss, hyperventilation, sweating and fatigue. At 1000 ppm, nearly all the occupants were affected. [...] In the event that the atmospheric concentration of carbon dioxide reaches 600 ppm, the planet will have a permanent outdoor atmosphere exactly like that of a stuffy room. The conditions indoors in buildings of the type now available will become even more unpleasant and could easily reach 1000 ppm permanently with the results outlined above.” D. S. Robertson, Current science, 2006, vol. 90, no12, pp. 1607-1609. [Full text]

Carbon Dioxide Poisoning – Langford (2005) “Carbon dioxide is a physiologically important gas, produced by the body as a result of cellular metabolism. It is widely used in the food industry in the carbonation of beverages, in fire extinguishers as an `inerting’ agent and in the chemical industry. Its main mode of action is as an asphyxiant, although it also exerts toxic effects at cellular level. At low concentrations, gaseous carbon dioxide appears to have little toxicological effect. At higher concentrations it leads to an increased respiratory rate, tachycardia, cardiac arrhythmias and impaired consciousness. Concentrations >10% may cause convulsions, coma and death. Solid carbon dioxide may cause burns following direct contact. If it is warmed rapidly, large amounts of carbon dioxide are generated, which can be dangerous, particularly within confined areas. The management of carbon dioxide poisoning requires the immediate removal of the casualty from the toxic environment, the administration of oxygen and appropriate supportive care. In severe cases, assisted ventilation may be required. Dry ice burns are treated similarly to other cryogenic burns, requiring thawing of the tissue and suitable analgesia. Healing may be delayed and surgical intervention may be required in severe cases.” Langford, Nigel J., Toxicological Reviews, Volume 24, Number 4, 2005 , pp. 229-235(7).

Association of Ventilation Rates and CO2 Concentrations with Health andOther Responses in Commercial and Institutional Buildings – Seppänen et al. (1999) “This paper reviews current literature on the associations of ventilation rates and carbon dioxide concentrations in non-residential and non-industrial buildings (primarily offices) with health and other human outcomes. Twenty studies, with close to 30,000 subjects, investigated the association of ventilation rates with human responses, and 21 studies, with over 30,000 subjects, investigated the association of carbon dioxide concentration with these responses. Almost all studies found that ventilation rates below 10 Ls-1 per person in all building types were associated with statistically significant worsening in one or more health or perceived air quality outcomes. Some studies determined that increases in ventilation rates above 10 Ls-1 per person, up to approximately 20 Ls-1 per person, were associated with further significant decreases in the prevalence of sick building syndrome (SBS) symptoms or with further significant improvements in perceived air quality. The carbon dioxide studies support these findings. About half of the carbon dioxide studies suggest that the risk of sick building syndrome symptoms continued to decrease significantly with decreasing carbon dioxide concentrations below 800 ppm. The ventilation studies reported relative risks of 1.5–2 for respiratory illnesses and 1.1–6 for sick building syndrome symptoms for low compared to high low ventilation rates.” O. A. Seppänen, W. J. Fisk, M. J. Mendell, Indoor Air, Volume 9, Issue 4, pages 226–252, December 1999, DOI: 10.1111/j.1600-0668.1999.00003.x. [Full text]

Indoor Air Quality Investigations at Five Classrooms – Lee & Chang (1999) “Five classrooms, air-conditioned or naturally ventilated, at five different schools were chosen for comparison of indoor and outdoor air quality. Temperature, relative humidity (RH), carbon dioxide (CO2), sulphur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), particulate matter with diameter less than 10 mm (PM10), formaldehyde (HCHO), and total bacteria counts were monitored at indoor and outdoor locations simultaneously. Respirable particulate matter was found to be the worst among parameters measured in this study. The indoor and outdoor average PM10 concentrations exceeded the Hong Kong standards, and the maximum indoor PM10 level was even at 472 μ;g/m3. Air cleaners could be used in classrooms to reduce the high PM10 concentration. Indoor CO2 concentrations often exceeded 1,000 μl/l indicating inadequate ventilation. Lowering the occupancy and increasing breaks between classes could alleviate the high CO2 concentrations. Though the maximum indoor CO2 level reached 5,900 μl/l during class at one of the sites, CO2 concentrations were still at levels that pose no health threats.” S. C. Lee, Maureen Chang, Indoor Air, Volume 9, Issue 2, pages 134–138, June 1999, DOI: 10.1111/j.1600-0668.1999.t01-2-00008.x.

Effects of sustained low-level elevations of carbon dioxide on cerebral blood flow and autoregulation of the intracerebral arteries in humans – Sliwka et al. (1998) “Cerebral blood flow velocity (CBFv) was measured by insonating the middle cerebral arteries of four subjects using a 2 Mhz transcranial Doppler. Ambient CO2 was elevated to 0.7% for 23 d in the first study and to 1.2% for 23 d in the same subjects in the second study. By non-parametric testing CBFv was elevated significantly by +35% above pre-exposure levels during the first 1-3 d at both exposure levels, after which CBFv progressively readjusted to pre-exposure levels. Despite similar CBFv responses, headache was only reported during the initial phase of exposure to 1.2% CO2. Vascular reactivity to CO2 assessed by rebreathing showed a similar pattern with the CBFv increases early in the exposures being greater than those elicited later. An increase in metabolic rate of the visual cortex was evoked by having the subjects open and close their eyes during a visual stimulus. Evoked CBFv responses measured in the posterior cerebral artery were also elevated in the first 1-3 d of both studies returning to pre-exposure levels as hypercapnia continued. Cerebral vascular autoregulation assessed by raising head pressure during 10 degrees head-down tilt both during the low-level exposures and during rebreathing was unaltered. There were no changes in the retinal microcirculation during serial fundoscopy studies. The time-dependent changes in CO2 vascular reactivity might be due either to retention of bicarbonate in brain extracellular fluid or to progressive increases in ventilation, or both. Cerebral vascular autoregulation appears preserved during chronic exposure to these low levels of ambient CO2.” Sliwka U, Krasney JA, Simon SG, Schmidt P, Noth J., Aviat Space Environ Med. 1998 Mar;69(3):299-306.

Sick Building Syndrome Symptoms among the Staff in Schools and Kindergartens: are the Levels of Volatile Organic Compounds and Carbon Dioxide Responsible? – Willers et al. (1996) “From a large questionnaire-based survey investigating the indoor air quality (IAQ) in 48 schools and 74 kindergartens, 21 schools were selected for mea surements of volatile organic compounds (VOC) and carbon dioxide (CO2) based on the prevalence of sick building syndrome (SBS) symptoms reported by the staff. The 10 schools with the lowest prevalence of SBS symptoms ‘healthy’) were compared to 11 schools with the highest prevalence (‘sick’; median value showing twice as many SBS symptoms reported). The concen trations of total VOCs (TVOC) in schools and kindergartens were low and within suggested guidelines. The levels of CO2 were higher than suggested guidelines in several cases. However, neither TVOC nor CO2 concentrations were associated with SBS symptoms. Thus, TVOC and CO2 concentrations do not seem to be useful as SBS risk indicators.” Stefan Willers, Sven Andersson, Rolf Andersson, Jörgen Grantén, Christina Sverdrup, Lars Rosell, Indoor and Built Environment July 1996 vol. 5 no. 4 232-235, doi: 10.1177/1420326X9600500406.

Effects of carbon dioxide inhalation on psychomotor and mental performance during exercise and recovery – Sheehy et al. (1982) “Psychomotor and mental tests involving reaction time, rotor pursuit, short-term memory for digits and letters, and reasoning ability were administered to subjects inhaling up to 5% CO2 in air and in gas mixtures containing 50% O2. The psychomotor and mental tests were given during the 6 min of recovery following 10 min of treadmill running at 80% of aerobic capacity. Although the subjects inhaled the CO2 during the entire exercise and recovery period there was no difference in performance between the CO2 inhalation condition and the control condition for any of the performance measures.” Sheehy, J B; Kamon, E; Kiser, D., Human Factors. Vol. 24, pp. 581-588. Oct. 1982.

Effects on man of high concentrations of carbon dioxide in relation to various oxygen pressures during exposures as long as 72 hours – Consolazio et al. (1947) No abstract. W. V. Consolazio, M. B. Fisher, N. Pace, I. J. Pecora, G. C. Pitts, A. R. Behnke, American Journal of Physiology, November 1947 vol. 151 no. 2 479-503.

Increasing atmospheric CO2 and allergies

Changes in Atmospheric CO2 Influence the Allergenicity of Aspergillus fumigatus – Lang-Yona et al. (2013) “Increased susceptibility to allergies has been documented in the Western world in recent decades. However, a comprehensive understanding of its causes is not yet available. It is therefore essential to understand trends and mechanisms of allergy-inducing agents, such as fungal conidia. In this study we investigated the hypothesis that environmental conditions linked to global atmospheric changes can affect the allergenicity of Aspergillus fumigatus, a common allergenic fungal species in indoor and outdoor environments and in airborne particulate matter. We show that fungi grown under present day CO2 levels (392 ppm) exhibit 8.5 and 3.5 fold higher allergenicity compared to fungi grown at preindustrial (280 ppm) and double (560 ppm) CO2 levels, respectively. A corresponding trend is observed in the expression of genes encoding for known allergenic proteins and in the major allergen Asp f1 concentrations, possibly due to physiological changes such as respiration rates and the nitrogen content of the fungus, influenced by the CO2 concentrations. Increased carbon and nitrogen levels in the growth medium also lead to a significant increase in the allergenicity. We propose that climatic changes such as increasing atmospheric CO2 levels and changes in the fungal growth medium may impact the ability of allergenic fungi such as Aspergillus fumigatus to induce allergies.” Naama Lang-Yona, Yishai Levin, Karen C. Dannemiller, Oded Yarden, Jordan Peccia, Yinon Rudich, Global Change Biology, DOI: 10.1111/gcb.12219.

Anthropogenic climate change and allergen exposure: The role of plant biology – Ziska & Beggs (2012) “Accumulation of anthropogenic gases, particularly CO2, is likely to have 2 fundamental effects on plant biology. The first is an indirect effect through Earth’s increasing average surface temperatures, with subsequent effects on other aspects of climate, such as rainfall and extreme weather events. The second is a direct effect caused by CO2-induced stimulation of photosynthesis and plant growth. Both effects are likely to alter a number of fundamental aspects of plant biology and human health, including aerobiology and allergic diseases, respectively. This review highlights the current and projected effect of increasing CO2 and climate change in the context of plants and allergen exposure, emphasizing direct effects on plant physiologic parameters (eg, pollen production) and indirect effects (eg, fungal sporulation) related to diverse biotic and abiotic interactions. Overall, the review assumes that future global mitigation efforts will be limited and suggests a number of key research areas that will assist in adapting to the ongoing challenges to public health associated with increased allergen exposure.” Lewis H. Ziska, Paul J. Beggs, Journal of Allergy and Clinical Immunology, Volume 129, Issue 1, January 2012, Pages 27–32, http://dx.doi.org/10.1016/j.jaci.2011.10.032.

Elevated atmospheric carbon dioxide concentrations amplify Alternaria alternata sporulation and total antigen production – Wolf et al. (2010) “BACKGROUND: Although the effect of elevated carbon dioxide (CO2) concentration on pollen production has been established in some plant species, impacts on fungal sporulation and antigen production have not been elucidated. OBJECTIVE: Our purpose was to examine the effects of rising atmospheric CO2 concentrations on the quantity and quality of fungal spores produced on timothy (Phleum pratense) leaves. METHODS: Timothy plants were grown at four CO2 concentrations (300, 400, 500, and 600 micromol/mol). Leaves were used as growth substrate for Alternaria alternata and Cladosporium phlei. The spore abundance produced by both fungi, as well as the size (microscopy) and antigenic protein content (ELISA) of A. alternata, were quantified. RESULTS: Leaf carbon-to-nitrogen ratio was greater at 500 and 600 micromol/mol, and leaf biomass was greater at 600 micromol/mol than at the lower CO2 concentrations. Leaf carbon-to-nitrogen ratio was positively correlated with A. alternata spore production per gram of leaf but negatively correlated with antigenic protein content per spore. At 500 and 600 micromol/mol CO2 concentrations, A. alternata produced nearly three times the number of spores and more than twice the total antigenic protein per plant than at lower concentrations. C. phlei spore production was positively correlated with leaf carbon-to-nitrogen ratio, but overall spore production was much lower than in A. alternata, and total per-plant production did not vary among CO2 concentrations. CONCLUSIONS: Elevated CO2 concentrations often increase plant leaf biomass and carbon-to-nitrogen ratio. Here we demonstrate for the first time that these leaf changes are associated with increased spore production by A. alternata, a ubiquitous allergenic fungus. This response may contribute to the increasing prevalence of allergies and asthma.” Wolf J, O’Neill NR, Rogers CA, Muilenberg ML, Ziska LH., Environ Health Perspect. 2010 Sep;118(9):1223-8. doi: 10.1289/ehp.0901867. [Full text]

Impacts of climate change on plant food allergens: a previously unrecognized threat to human health – Beggs & Walczyk (2008) “Global climate change has had, and will continue to have, many significant impacts on biological and human systems. There are now many studies of climate change impacts on aeroallergens, particularly pollen, including a study demonstrating significant increases in the major allergen content of ragweed pollen as a function of rising atmospheric carbon dioxide concentration ([CO2]). Recent research has also demonstrated more allergenic poison ivy in response to elevated [CO2]. Here, we suggest, for the first time, the potential for global climate change, and, in particular, increased [CO2] and temperature, to have an impact on the allergenicity of plant food allergens such as peanut. Such impacts could have significant impacts on associated allergic diseases, and pose a previously unrecognized threat to human health. There is an urgent need for research on the impacts of climate change on plant food allergens.” Paul John Beggs, Nicole Ewa Walczyk, Air Quality, Atmosphere & Health, October 2008, Volume 1, Issue 2, pp 119-123, DOI: 10.1007/s11869-008-0013-z. [Full text]

Pollen production by Pinus taeda growing in elevated atmospheric CO2 – Ladeau & Clark (2006) “Rising concentrations of atmospheric CO2 may have important consequences for reproductive allocation in forest trees. Changes in pollen production could influence population dynamics and is likely to have important consequences for human health. This is the first study to evaluate pollen production by forest trees in response to rising atmospheric CO2. Our research objective was to quantify pollen production by Loblolly Pine (Pinus taeda L.) trees growing in elevated CO2 (ambient + 200 µl l−1) since 1996. Trees grown in high-CO2 plots first began producing pollen while younger and at smaller sizes relative to ambient-grown trees. Pollen cone and airborne pollen grain abundances were significantly greater in the fumigated stands. We conclude that the greater number of mature trees in high-CO2 plots resulted in greater pollen production at the stand level. Precocious pollen production has important implications for fertilization and pollen dispersal from young, dense stands. Increasing levels of airborne pollen raise concerns for escalating rates of human respiratory disease.” S. L. Ladeau, J. S. Clark, Functional Ecology, Volume 20, Issue 3, pages 541–547, June 2006, DOI: 10.1111/j.1365-2435.2006.01133.x. [Full text]

Biomass and toxicity responses of poison ivy (Toxicodendron radicans) to elevated atmospheric CO2 – Mohan et al. (2006) “Contact with poison ivy (Toxicodendron radicans) is one of the most widely reported ailments at poison centers in the United States, and this plant has been introduced throughout the world, where it occurs with other allergenic members of the cashew family (Anacardiaceae). Approximately 80% of humans develop dermatitis upon exposure to the carbon-based active compound, urushiol. It is not known how poison ivy might respond to increasing concentrations of atmospheric carbon dioxide (CO2), but previous work done in controlled growth chambers shows that other vines exhibit large growth enhancement from elevated CO2. Rising CO2 is potentially responsible for the increased vine abundance that is inhibiting forest regeneration and increasing tree mortality around the world. In this 6-year study at the Duke University Free-Air CO2 Enrichment experiment, we show that elevated atmospheric CO2 in an intact forest ecosystem increases photosynthesis, water use efficiency, growth, and population biomass of poison ivy. The CO2 growth stimulation exceeds that of most other woody species. Furthermore, high-CO2 plants produce a more allergenic form of urushiol. Our results indicate that Toxicodendron taxa will become more abundant and more “toxic” in the future, potentially affecting global forest dynamics and human health.” Jacqueline E. Mohan, Lewis H. Ziska, William H. Schlesinger, Richard B. Thomas, Richard C. Sicher, Kate George, and James S. Clark, PNAS June 13, 2006 vol. 103 no. 24 9086-9089, doi: 10.1073/pnas.0602392103. [Full text]

Increasing Amb a 1 content in common ragweed (Ambrosia artemisiifolia) pollen as a function of rising atmospheric CO2 concentration – Singer et al. (2005) “Although the impact of increasing atmospheric carbon dioxide concentration ([CO2]) on production of common ragweed (Ambrosia artemisiifolia L.) pollen has been examined in both indoor and outdoor experiments, the relationship between allergen expression and [CO2] is not known. An enzyme-linked immunosorbent assay (ELISA) was used to quantify Amb a 1, ragweed’s major allergen, in protein extracted from pollen of A. artemisiifolia grown at different [CO2] values in a previous experiment. The concentrations used approximated atmospheric pre-industrial conditions (i.e. at the end of the 19th century), current conditions, and the CO2 concentration projected for the middle of the 21st century (280, 370 and 600 μmol mol–1 CO2, respectively). Although total pollen protein remained unchanged, significant increases in Amb a 1 allergen were observed between pre-industrial and projected future [CO2] and between current and projected future [CO2] (1.8 and 1.6 times, respectively). These data suggest that recent and projected increases in [CO2] could directly increase the allergenicity of ragweed pollen and consequently the prevalence and / or severity of seasonal allergic disease. However, genetic and abiotic factors governing allergen expression will need to be better established to fully understand these data and their implications for public health.” Ben D. Singer A C, Lewis H. Ziska B D, David A. Frenz C, Dennis E. Gebhard C, James G. Straka, Functional Plant Biology 32(7) 667–670, http://dx.doi.org/10.1071/FP05039. [Full text]

Production of allergenic pollen by ragweed (Ambrosia artemisiifolia L.) is increased in CO2-enriched atmospheres – Wayne et al. (2002) “Background: The potential effects of global climate change on allergenic pollen production are still poorly understood. Objective: To study the direct impact of rising atmospheric CO2 concentrations on ragweed (Ambrosia artemisiifolia L.) pollen production and growth. Methods: In environmentally controlled greenhouses, stands of ragweed plants were grown from seed through flowering stages at both ambient and twice-ambient CO2 levels (350 vs 700 μL L−1). Outcome measures included stand-level total pollen production and end-of-season measures of plant mass, height, and seed production. Results: A doubling of the atmospheric CO2 concentration stimulated ragweed-pollen production by 61% (P = 0.005). Conclusions: These results suggest that there may be significant increases in exposure to allergenic pollen under the present scenarios of global warming. Further studies may enable public health groups to more accurately evaluate the future risks of hay fever and respiratory diseases (eg, asthma) exacerbated by allergenic pollen, and to develop strategies to mitigate them.” Peter Wayne, Susannah Foster, John Connolly, Fakhri Bazzaz, Paul Epstein, Annals of Allergy, Asthma & Immunology, Volume 88, Issue 3, March 2002, Pages 279–282, http://dx.doi.org/10.1016/S1081-1206(10)62009-1. [Full text]

Rising CO2 and pollen production of common ragweed (Ambrosia artemisiifolia L.), a known allergy-inducing species: implications for public health – Ziska & Caulfield (2000) “Although environmental factors such as precipitation and temperature are recognized as influencing pollen production, the impact of rising atmospheric carbon dioxide concentration ([CO2]) on the potential growth and pollen production of hay-fever-inducing plants is unknown. Here we present measurements of growth and pollen production of common ragweed (Ambrosia artemisiifolia L.) from pre-industrial [CO2] (280 mol mol–1) to current concentrations (370 mol mol–1) to a projected 21st century concentration (600 mol mol–1). We found that exposure to current and elevated [CO2] increased ragweed pollen production by 131 and 320%, respectively, compared to plants grown at pre-industrial [CO2]. The observed stimulations of pollen production from the pre-industrial [CO2] were due to an increase in the number (at 370 mol mol–1) and number and size (at 600 mol mol–1) of floral spikes. Overall, floral weight as a percentage of total plant weight decreased (from 21% to 13%), while investment in pollen increased (from 3.6 to 6%) between 280 and 600 mol mol–1 CO2. Our results suggest that the continuing increase in atmospheric [CO2] could directly influence public health by stimulating the growth and pollen production of allergy-inducing species such as ragweed.” Lewis H. Ziska and Frances A. Caulfield, Australian Journal of Plant Physiology 27(10) 893 – 898, doi:10.1071/PP00032. [Full text]

Increased levels of airborne fungal spores in response to Populus tremuloides grown under elevated atmospheric CO2 – Klironomos et al. (1997) “Soil fungi are important components of terrestrial ecosystems. They function as decomposers, pathogens, parasites, and mutualistic symbionts. Their main mode of dispersal is to liberate spores into the atmosphere. In this study we tested the hypothesis that a higher atmospheric CO2 concentration will induce greater sporulation in common soil fungi, leading to higher concentrations of fungal propagules in the atmosphere. In our field experiment, the concentration of airborne fungal propagules, mostly spores, increased fourfold under twice-ambient CO2 concentrations. Analysis of decomposing leaf litter (likely the main source of airborne fungal propagules) indicated that the fungi produced fivefold more spores under elevated CO2. Our results provide evidence that elevations in atmospheric CO2 concentration can directly affect microbial function, which may have important implications for litter decay, fungal dispersal, and human respiratory health. Key words: atmospheric CO2, fungal spores, global change, Populus tremuloides.” John N. Klironomos, Matthias C. Rillig, Michael F. Allen, Donald R. Zak, Kurt S. Pregitzer, Mark E. Kubiske, Canadian Journal of Botany, 1997, 75(10): 1670-1673, 10.1139/b97-880.

Extreme carbon dioxide events

This section lists papers on some extreme events where carbon dioxide has caused deaths or serious harm. It should be noted that this is not very relevant to the carbon dioxide levels associated with current global warming. However, for some carbon capture and storage scenarios these events serve as practical examples to what happens during high local carbon dioxide levels.

Non-volcanic CO2 Earth degassing: Case of Mefite d’Ansanto (southern Apennines), Italy – Chiodini et al. (2010) “Mefite d’Ansanto, southern Apennines, Italy is the largest natural emission of low temperature CO2 rich gases, from non-volcanic environment, ever measured in the Earth. The emission is fed by a buried reservoir, made up of permeable limestones and covered by clayey sediments. We estimated a total gas flux of ~2000 tons per day. Under low wind conditions, the gas flows along a narrow natural channel producing a persistent gas river which has killed over a period of time people and animals. The application of a physical numerical model allowed us to define the zones which potentially can be affected by dangerous CO2 concentration at breathing height for humans.” Chiodini, G., D. Granieri, R. Avino, S. Caliro, A. Costa, C. Minopoli, and G. Vilardo (2010), Geophys. Res. Lett., 37, L11303, doi:10.1029/2010GL042858.

Asphyxiation Due to Dry Ice in a Walk-in Freezer – Dunford et al. (2009) “Background: Exposure to a high concentration of environmental carbon dioxide (CO2) can result in poisoning through direct toxicity and by displacing atmospheric oxygen (O2). Dry ice undergoes sublimation to a gaseous state at −78.5°C (−109.3°F), which is heavier than air and can accumulate in dependent areas. Case Report: We report the case of a 59-year-old man found in cardiac arrest shortly after entering a recently repaired walk-in freezer that contained dry ice. First responders and bystanders did not recognize the proximate hazardous environment but were fortunately uninjured. A careful Emergency Department history coupled with rapid case investigation by the Medical Examiner’s Office led to the determination of the cause of death and the elimination of the ongoing hazard. Conclusion: This case illustrates the lethal consequences of improper storage of dry ice and the need to consider toxic environmental exposure as a cause of sudden cardiac arrest.” James V. Dunford, Jon Lucas, Nick Vent, Richard F. Clark, F. Lee Cantrell, The Journal of Emergency Medicine, Volume 36, Issue 4, May 2009, Pages 353-356, doi:10.1016/j.jemermed.2008.02.051.

A Carbon Dioxide Fatality from Dry Ice – Srisont et al. (2009) “This report documents a rare case of carbon dioxide intoxication in a young healthy male. The deceased hid in a small plastic container, size 1.5 × 1 × 1 m, and within 5 min he was located suffering convulsions and was reported as dead within minutes. Scene investigation revealed dry ice in the container. Autopsy findings were unremarkable. The probable cause of the convulsions was carbon dioxide intoxication due to both the dry ice sublimation and the small confined space in which he was hiding. This report emphasizes the significance of scene investigation in establishing the cause of the death.” Smith Srisont, Thamrong Chirachariyavej, A. V. M. Vichan Peonim, Journal of Forensic Sciences, Volume 54, Issue 4, pages 961–962, July 2009, DOI: 10.1111/j.1556-4029.2009.01057.x. [Full text]

A shallow-layer model for heavy gas dispersion from natural sources: Application and hazard assessment at Caldara di Manziana, Italy – Costa et al. (2008) “Several nonvolcanic sources in central Italy emit a large amount of carbon dioxide (CO2). Under stable atmospheric conditions and/or in the presence of topographic depressions, the concentration of CO2, which has a molecular mass greater than that of air, can reach high values that are lethal to humans or animals. Several episodes of this phenomenon were recorded in central Italy and elsewhere. In order to validate a model for the dispersion of a heavy gas and to assess the consequent hazard, we applied and tested the code TWODEE-2, an improved version of the established TWODEE model, which is based on a shallow-layer approach that uses depth-averaged variables to describe the flow behavior of dense gas over complex topography. We present results for a vented CO2 release at Caldara di Manziana in central Italy. We find that the model gives reliable results when the input quantity can be properly defined. Moreover, we show that the model can be a useful tool for gas hazard assessment by evaluating where and when lethal concentrations for humans and animals are reached.” Costa, A., G. Chiodini, D. Granieri, A. Folch, R. K. S. Hankin, S. Caliro, R. Avino, and C. Cardellini (2008), Geochem. Geophys. Geosyst., 9, Q03002, doi:10.1029/2007GC001762. [Full text]

Degassing Lakes Nyos and Monoun: Defusing certain disaster – Kling et al. (2005) “Since the catastrophic releases of CO2 in the 1980s, Lakes Nyos and Monoun in Cameroon experienced CO2 recharge at alarming rates of up to 80 mol/m2 per yr. Total gas pressures reached 8.3 and 15.6 bar in Monoun (2003) and Nyos (2001), respectively, resulting in gas saturation levels up to 97%. These natural hazards are distinguished by the potential for mitigation to prevent future disasters. Controlled degassing was initiated at Nyos (2001) and Monoun (2003) amid speculation it could inadvertently destabilize the lakes and trigger another gas burst. Our measurements indicate that water column structure has not been compromised by the degassing and local stability is increasing in the zones of degassing. Furthermore, gas content has been reduced in the lakes ≈12-14%. However, as gas is removed, the pressure at pipe inlets is reduced, and the removal rate will decrease over time. Based on 12 years of limnological measurements we developed a model of future removal rates and gas inventory, which predicts that in Monoun the current pipe will remove ≈30% of the gas remaining before the natural gas recharge balances the removal rate. In Nyos the single pipe will remove ≈25% of the gas remaining by 2015; this slow removal extends the present risk to local populations. More pipes and continued vigilance are required to reduce the risk of repeat disasters. Our model indicates that 75-99% of the gas remaining would be removed by 2010 with two pipes in Monoun and five pipes in Nyos, substantially reducing the risks.” George W. Kling, William C. Evans, Greg Tanyileke, Minoru Kusakabe, Takeshi Ohba, Yutaka Yoshida, and Joseph V. Hell, PNAS October 4, 2005 vol. 102 no. 40 14185-14190, doi: 10.1073/pnas.0502274102. [Full text]

Recent pH and CO2 profiles at Lakes Nyos and Monoun, Cameroon: implications for the degassing strategy and its numerical simulation – Kusakabe et al. (2000) “In situ pH profiles are reported for the first time for Lakes Nyos and Monoun. The pH profiles were converted to CO2 profiles using HCO3− profiles calculated from conductivity data. Recent observations (1993–1996) at Lake Nyos indicates that CO2 still accumulates below 180 m depth at a rate of 125 Mmol year−1. At Lake Monoun, the majority of CO2 is present below a depth of 60 m, only 25 m below the saturation depth. Consequently, a potential danger of gas explosion is high at both lakes, and artificial degassing of the lakes should be performed as soon as possible. A system for industrial degassing of the lakes is proposed. The system, based on the self-sustained gas lift principle, consists of multiple pipes (14 cm in diameter) with different intake depths; 12 pipes for Lake Nyos (four each at 185, 195 and 205 m) and three pipes for Lake Monoun (at 70, 80 and 90 m). The stepped degassing at different depths is intended to keep the maximum stability of the lakes. The proposed degassing operation was simulated using the dyresm code for both lakes. In 5 years, approximately 50% of currently dissolved CO2 in Lake Nyos and 90% in Lake Monoun will be removed. The expected changes in the thermal and chemical structures of the lakes as degassing proceeds will be most easily monitored with a carefully calibrated CTD equipped with a pH sensor. The simulation indicates that the discharged degassed water will sink to a level of neutral buoyancy, i.e. to a maximum of 70 m at Lake Nyos and 35 m at Lake Monoun. There would be no possibility of triggering a gas explosion by this plunge of discharged water because the water present there would have already been replaced by water at lower CO2 concentration, during the degassing from shallower pipes.” M Kusakabe, G.Z Tanyileke, S.A McCord, S.G Schladow, Journal of Volcanology and Geothermal Research, Volume 97, Issues 1-4, April 2000, Pages 241-260, doi:10.1016/S0377-0273(99)00170-5.

Possible asphyxiation from carbon dioxide of a cross-country skier in eastern California: a deadly volcanic hazard – Hill (2000) “This report describes an incident in which exceedingly high levels of carbon dioxide may have contributed to the death of a skier in eastern California. A cross-country skier was found dead inside a large, mostly covered snow cave, 1 day after he was reported missing. The autopsy report suggests that the skier died of acute pulmonary edema consistent with asphyxiation; carbon dioxide measurements inside the hole in which he was found reached 70%. This area is known for having a high carbon dioxide flux attributed to degassing of a large body of magma (molten rock) 10 to 20 km beneath the ski area. The literature describes many incidents of fatal carbon dioxide exposures associated with volcanic systems in other parts of the world. We believe this case represents the first reported death associated with volcanically produced carbon dioxide in the United States. Disaster and wilderness medicine specialists should be aware of and plan for this potential health hazard associated with active volcanoes.” Peter M. Hill, Wilderness & Environmental Medicine, Volume 11, Issue 3, September 2000, Pages 192-195, doi:10.1580/1080-6032(2000)011[0192:PAFCDO]2.3.CO;2.

Fatal intoxication due to an unexpected presence of carbon dioxide – Guillemin & Horisberger (1994) “A fatal accident which occurred in a tank containing a sludge made of wine and activated charcoal is described. Similar accidents in the wine industry seem to have never been reported before. Initially, the cause of death was not obvious and became clear only after the autopsy confirmed the presence of a very high concentration of carbon dioxide in blood. It is shown in this paper how the concentration of carbon dioxide in the tank could be estimated from its solubility in water, assuming a realistic content of this gas in the wine remaining in the sludge. Moreover the accident was analysed by the fault tree method which revealed that, as well as the deficiencies in risk management of such companies, the unsuspected presence of carbon dioxide played a significant role.” Michel P. Guillemin and B. Horisberger, Ann Occup Hyg (1994) 38 (6): 951-957. doi: 10.1093/annhyg/38.6.951.

CO2-rich gases from Lakes Nyos and Monoun, Cameroon; Laacher See, Germany; Dieng, Indonesia, and Mt. Gambier, Australia—variations on a common theme – Giggenbach et al. (1991) “Helium (RA = 3.0 to 5.6) and carbon (δ13C from −7.2 to −3.4‰) isotopic compositions, and relative CO2, CH4, N2, He and Ar contents of CO2-rich gases from Lakes Nyos and Monoun, Cameroon; Laacher See, Germany; Dieng Volcanic Plateau, Indonesia, and a well at Mt. Gambier, Australia, point to a common, essentially magmatic origin. … Otherwise, gas may accumulate to form a stable pocket (Mt. Gambier). Minor leakage from such pockets may lead to surface discharges of CO2-rich gases as at Laacher See, re-absorption into shallow groundwater to the formation of the low-salinity, CO2-charged waters encountered at Lakes Nyos and Monoun. The occurrence of these high-CO2, low-temperature systems is likely to be favored in tectonically active regions, allowing deep, possibly mantle gases to rise, but with sufficiently low regional heat flows to prevent the establishment of large-scale geothermal activity.” W.F. Giggenbach, Y. Sano, H.U. Schmincke, Journal of Volcanology and Geothermal Research, Volume 45, Issues 3-4, April 1991, Pages 311-323, doi:10.1016/0377-0273(91)90065-8.

Water and gas chemistry of Lake Nyos and its bearing on the eruptive process – W.F. Giggenbach (1990) “The isotopic and chemical composition of water samples collected from Lake Nyos some two and eight weeks after the eruption of August 21, 1986 point to the existence of three distinct mixing regimes involving three water components. An essentially homogeneous, unmixed body of water at depths > 100 m, overlain by water increasingly affected by surface evaporation and a 5–10-m layer containing recent, but pre-eruption rain water. The cationic constituents (Na, K, Mg, Ca, Mn, Fe) of the lake water correspond to the dissolution of around 0.1 g of local rock, the waters are close to saturation with respect to siderite. The composition of the gas dissolved in the deep lake waters (0.65% b.w. of CO2, PCO2 = 4.4b) corresponds (in mmol mol−1) to 996 CO2, 2.0 CH4, 2.0 N2, 0.05 Ar, 0.004 He, 0.0002 H2, 0.0001 Ne, < 0.01 O2, < 0.004 H2S, < 0.001 CO. The isotopic compositions of CO213C = -3.4‰) and of He (Rair = 5.5) suggest deep magmatic origins, the 13C and 2H content of CH4 organic sedimentary origin, the presence of aromatic hydrocarbons indicates very high temperatures of hydrocarbon formation. Exsolution of gas will first lead to the precipitation of siderite then iron hydroxide. The chemistry of the lake waters points to a loss of some 240,000 t of CO2 from the upper 100 m of the lake, their isotopic composition is consistent with the assumption that the eruption was triggered by the accumulation of cold rain waters at the lake surface prior to the eruption inducing partial convective overturn. There is no need to invoke addition of chemical or isotopic constituents from deeper levels during the eruption.” W.F. Giggenbach, Journal of Volcanology and Geothermal Research, Volume 42, Issue 4, 15 August 1990, Pages 337-362, doi:10.1016/0377-0273(90)90031-A.

The Lake Nyos gas disaster: chemical and isotopic evidence in waters and dissolved gases from three Cameroonian crater lakes, Nyos, Monoun and Wum – Kusakabe et al. (1989) “To better understand the cause of the Nyos gas disaster of August 21, 1986, we conducted geochemical and limnological surveys in October 1986, of three lakes (Nyos, Monoun and Wum) which are located in the Cameroon volcanic zone that is characterized by a prevalence of young alkaline basalts and basanitoids. … The August 1986 gas bursts from Lake Nyos were most likely caused by rapid exsolution of dissolved CO2 within the lake; an explosive process such as a phreatic eruption or a CO2 gas-jetting from beneath the bottom is unlikely because of low concentrations of Cl and SO42−, no oxygen isotopic shift, low turbidity, and no reported perturbation of the bottom sediments. Exsolution of CO2 bubbles could occur if CO2-saturated bottom water was displaced upwards by an increased influx of high salinity water from the bottom during the rainy season. Exsolution of CO2 at the upper layers was possibly accelerated by upwelling of a two-phase fluid (CO2 bubbles and solution), a mechanism known as a pneumatic lift pump, resulting in discharge of a large amount of CO2 gas. The H2S concentration in the gas cloud must have been kept far below the lethal level because of a high Fe2+ concentration of the lake water.” Minoru Kusakabe, Takashi Ohsumi, Shigeo Aramaki, Journal of Volcanology and Geothermal Research, Volume 39, Issues 2-3, November 1989, Pages 167-185, doi:10.1016/0377-0273(89)90056-5.

The gas cloud of Lake Nyos (Cameroon, 1986): Results of the Italian technical mission – Barberi et al. (1989) “On August 21, 1986, a gas cloud issued from Lake Nyos in Cameroon killed over 1700 people. An Italian technical mission reached the area seven days later and obtained the first field evidences of the catastrophe. On the basis of observations and measurements in the field and of samples collected, the origin of the gas outburst is attributed to a phreatic explosion from beneath the bed of the lake. This interpretation appears to fit well the observed and reported phenomena, and seems perfectly consistent with the geological-geothermal conditions of the area.” F. Barberi, W. Chelini, G. Marinelli, M. Martini, Journal of Volcanology and Geothermal Research, Volume 39, Issues 2-3, November 1989, Pages 125-134, doi:10.1016/0377-0273(89)90053-X.

Lake Nyos disaster, Cameroon, 1986: the medical effects of large scale emission of carbon dioxide? – Baxter et al. (1989) “Carbon dioxide was blamed for the deaths of around 1700 people in Cameroon, west Africa, in 1986 when a massive release of gas occurred from Lake Nyos, a volcanic crater lake. The clinical findings in 845 survivors seen at or admitted to hospital were compatible with exposure to an asphyxiant gas. Rescuers noted cutaneous erythema and bullae on an unknown proportion of corpses and 161 (19%) survivors treated in hospital; though these lesions were initially believed to be burns from acidic gases, further investigation suggested that they were associated with coma states caused by exposure to carbon dioxide in air. The disaster at Lake Nyos and a similar event at Lake Monoun, Cameroon, two years previously provide new information on the possible medical effects of large scale emissions of carbon dioxide, though the presence of other toxic factors in these gas releases cannot be excluded.” P. J. Baxter, M. Kapila, D. Mfonfu, BMJ 298 : 1437 doi: 10.1136/bmj.298.6685.1437 (Published 27 May 1989). [Full text]

Mechanisms of the Nyos carbon dioxide disaster and of so-called phreatic steam eruptions – Tazieff (1989) “During the night of August 21, 1986, a huge volume of concentrated CO2 was emitted by the crater (maar) of Nyos, Cameroon. It killed more than 1700 people and all animal life as far as 14 km away. Two hypotheses have been put forward to account for this disaster. The chronologically first one imputes it to have been a phreatic eruption, exceptionally CO2-rich, as had been the case in February 1979 on the Diëng Plateau in Central Java, Indonesia, where the erupting crater was lake-less. The second one claims a limnic origin for the CO2 release, through an overturn of the 220 m-deep Lake Nyos, the hypolimnium of which was supposed to be oversaturated by dissolved gas of volcanic origin. The present paper points to six observed facts for which the eruptive hypothesis easily accounts, and which the authors of the limnic one do ignore.” Haroun Tazieff, Journal of Volcanology and Geothermal Research, Volume 39, Issues 2-3, November 1989, Pages 109-116, doi:10.1016/0377-0273(89)90051-6.

Origin of carbon dioxide emanation from the 1979 Dieng eruption, Indonesia: Implications for the origin of the 1986 Nyos catastrophe – Allard et al. (1989) “In February 1979, CO2 emanations accompanying a phreatic eruption killed 142 people at Dieng volcano, Central Java. The gas emitted was nearly pure carbon dioxide, with subordinate amounts of methane and sulfur compounds. … It is proposed that magmatic carbon dioxide, accumulated beneath the Dieng volcanic complex, was the source of the lethal gas, the effusion of which was triggered by the pressure release generated by the phreatic eruption. The total CO2 discharge of the 1979 Dieng event might have approached 0.1 km3, i.e. close to the lower output estimated for the 1986 Nyos catastrophe. The Dieng example demonstrates that expansion and then effusion of pure magmatic carbon dioxide, accumulated at shallow levels beneath volcanoes, may account for a major hazard from phreatic eruptions, be it a trigger or only a consequence of the eruptions.” P. Allard, D. Dajlevic, C. Delarue, Journal of Volcanology and Geothermal Research, Volume 39, Issues 2-3, November 1989, Pages 195-206, doi:10.1016/0377-0273(89)90058-9.

Medical evaluation of the victims of the 1986 Lake Nyos disaster – Wagner et al. (1988) “A cloud of carbon dioxide gas, with an estimated volume of 1 km3 was released from Lake Nyos, a volcanic crater lake in Cameroon, Africa, causing 1700 to 2000 human fatalities as well as killing thousands of livestock and wild animals. At the request of the Cameroonian Government, the Office of Foreign Disaster Assistance of the U.S. Department of State sent a multidisciplinary team which included 2 forensic pathologists to assist the Government of Cameroon in investigating this natural disaster. The medical evaluation was concentrated in 3 areas: the autopsy of human and animal fatalities, examination and interview of survivors, and examination of the scene of the disaster. Toxicologic specimens were obtained at autopsy, and numerous samples of lake water were collected. The autopsy findings were consistent with asphyxia. The results of chemical analyses excluded many volatiles but not carbon dioxide as the toxic agent. The exact source of this gas continues to be a subject of a heated geologic debate, but fermentation of organic materials in the lake water has been eliminated on the basis of C14 isotope studies. This investigation underlines the value of forensic pathologists in epidemiological studies and in the examination of living persons.” Wagner GN, Clark MA, Koenigsberg EJ, Decata SJ., J Forensic Sci. 1988 Jul;33(4):899-909.

The 1986 Lake Nyos Gas Disaster in Cameroon, West Africa – Kling et al. (1987) “The sudden, catastrophic release of gas from Lake Nyos on 21 August 1986 caused the deaths of at least 1700 people in the northwest area of Cameroon, West Africa. Chemical, isotopic, geologic, and medical evidence support the hypotheses that (i) the bulk of gas released was carbon dioxide that had been stored in the lake’s hypolimnion, (ii) the victims exposed to the gas cloud died of carbon dioxide asphyxiation, (iii) the carbon dioxide was derived from magmatic sources, and (iv) there was no significant, direct volcanic activity involved. The limnological nature of the gas release suggests that hazardous lakes may be identified and monitored and that the danger of future incidents can be reduced.” George W. Kling, Michael A. Clark, Glen N. Wagner, Harry R. Compton, Alan M. Humphrey, Joseph D. Devine, William C. Evans, John P. Lockwood, Michele L. Tuttle and Edward J. Koenigsberg, Science 10 April 1987: Vol. 236 no. 4798 pp. 169-175, DOI: 10.1126/science.236.4798.169.

Origin of the lethal gas burst from Lake Monoun, Cameroun – Sigurdsson et al. (1987) “On 15 August, 1984, a lethal gas burst issued from a submerged 96-m-deep crater in Lake Monoun in Cameroun, western Africa, killing 37 people. The event was associated with a landslide from the eastern crater rim, which slumped into deep water. … Gases effervescing from depressurized deep waters are dominantly CO2 with minor CH4, having δ13C of −7.18 and −54.8 per mil, respectively. … The resultant ebullition of CO2 from deep lake waters led to a gas burst at the surface and locally generated a water wave up to 5 m high. People travelling through the gas cloud were asphyxiated, presumably from CO2, and suffered skin discoloration from unidentified components.” H. Sigurdsson, J.D. Devine, F.M. Tchua, F.M. Presser, M.K.W. Pringle, W.C. Evans, Journal of Volcanology and Geothermal Research, Volume 31, Issues 1-2, March 1987, Pages 1-16, doi:10.1016/0377-0273(87)90002-3.

An example of health hazard: People killed by gas during a phreatic eruption: Diëng plateau (Java, Indonesia), February 20th 1979 – Le Guern et al. (1982) “On February 20th, 1979, 142 inhabitants of Dieng Plateau (Indonesia) were asphyxiated by poisonous gases during a mild phreatic eruption. From later fields gas collection and analysis, the casualties are considered to be due to CO2 rich volcanic gases.” F. Le Guern, H. Tazieff and R. Faivre Pierret, Bulletin of Volcanology, Volume 45, Number 2, 153-156, DOI: 10.1007/BF02600430.

Posted in Adaptation & Mitigation, Global warming effects | 4 Comments »

The climate commitment of new Finnish government

Posted by Ari Jokimäki on June 17, 2011

Looks like Finland is finally getting a new government after long negotiations. Here are the relevant sections regarding climate change of the negotiation result of the new Finnish government (link is to a Finnish text) translated by me quickly and roughly. First, in the summary they say:

Environment will be left in better shape to future generations. Finland will be reformed as a forerunner in nourishing biodiversity and preventing climate change. The goals of the government are to make future Finland a carbon neutral society, to make Finland a number one country in environmental technology, and to develop Finland into a most knowledgeable nation on environment.

Then, section 9 deals with climate policy:

Finland will participate actively to the international co-operation for solving the environmental challenges.

In UN level the goal is to have a cogent and effective climate treaty, which takes biodiversity and other goals of sustainable development into consideration, and which limits the global warming to two degrees.

It will be investigated what effects the EU goal of 30 % emission cuts from 1990 level by 2020 would have. The investigation will find out the effects of changing the goal to costs, society, competitiveness, and compatibility with the two degree goal considering other commitments of EU countries. By the end of 2012 the government decides to support the 30 % goal if the investigation qualifies it.

The government will advance the achieving of the energy efficiency goals of EU determinedly. In 2013 progress in Finland will be evaluated in order to decide of possible additional actions.

The most cost-effecient way to proceed towards 80% emission cuts by 2050 is to steer the investments of energy production and use towards the improvement of energy efficiency and utilization of renewable energy in early stage. The effects to economy, to employment, and to distribution of wealth will be investigated during the preparation and decision-making of climate politics.

In order to achieve the climate goals, the government will make a long term EU strategy of climate policy. Finland should influence the policy decisions of European union in such a way, that the competitive status of the actors under European Union stays reasonable compared to the competitive status of the external actors and that the internal competitive situation of European Union will not be distorted.

The government will advance the chances of Finland to survive and gain from the coming energy and climate challenges. By investing to the research, development and application of climate and environmental technology and also to the services and know-how in the field the chances of Finland to become the heading country in low emission solutions will be improved. The co-operation with Nordic countries will be strengthened in the field of climate policy.

In EU Finland will support the carbon sink calculation methods, which are based on scientifically determine monitoring of true changes in carbon sinks, and which secures the sustainable economical use of forests. The goal is to have a fair system of global climate change prevention.

The government acknowledges the uneven distribution of climate change effects globally and the probelmatic relation of climate change and poverty. Finland will participate the international climate funding according to its commitments. The government supports the coordination of climate policy with development policy and explores the chances to take innovative funding instruments into use in climate policy.

Government will set a ministrial working group to update the national climate and energy strategy by the end of 2012. According to the future briefing of climate and energy policy, a multidisclipinary and independent climate panel will be formed to follow the actualization and effectiveness of the strategy. The climate panel will prepare directional emission budgets for government, which will aid towards long term sustainable emission levels. The climate panel will advice government in defining and checking of the emission budgets, monitors them to be taken in use, and gives recommendations on actions to reduce emissions. By gained experience and investigations the government will prepare a bill and makes separate decision to set a climate law to steer the reductions of emissions that are outside the emissions trading.

Posted in Adaptation & Mitigation | 1 Comment »

Papers on gas leakage from natural gas industry

Posted by Ari Jokimäki on April 13, 2011

This is a list of papers on gas leakage from natural gas industry. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (January 23, 2014): Miller et al. (2013), Karion et al. (2013), Allen et al. (2013), Pétron et al. (2012), Alvarez et al. (2012) added.
UPDATE (February 5, 2012): Howarth et al. (2011), Cathles et al. (2012), and Howarth et al. (2012) added.

Anthropogenic emissions of methane in the United States – Miller et al. (2013) “This study quantitatively estimates the spatial distribution of anthropogenic methane sources in the United States by combining comprehensive atmospheric methane observations, extensive spatial datasets, and a high-resolution atmospheric transport model. Results show that current inventories from the US Environmental Protection Agency (EPA) and the Emissions Database for Global Atmospheric Research underestimate methane emissions nationally by a factor of ∼1.5 and ∼1.7, respectively. Our study indicates that emissions due to ruminants and manure are up to twice the magnitude of existing inventories. In addition, the discrepancy in methane source estimates is particularly pronounced in the south-central United States, where we find total emissions are ∼2.7 times greater than in most inventories and account for 24 ± 3% of national emissions. The spatial patterns of our emission fluxes and observed methane–propane correlations indicate that fossil fuel extraction and refining are major contributors (45 ± 13%) in the south-central United States. This result suggests that regional methane emissions due to fossil fuel extraction and processing could be 4.9 ± 2.6 times larger than in EDGAR, the most comprehensive global methane inventory. These results cast doubt on the US EPA’s recent decision to downscale its estimate of national natural gas emissions by 25–30%. Overall, we conclude that methane emissions associated with both the animal husbandry and fossil fuel industries have larger greenhouse gas impacts than indicated by existing inventories.” Scot M. Miller, Steven C. Wofsy, Anna M. Michalak, Eric A. Kort, Arlyn E. Andrews, Sebastien C. Biraud, Edward J. Dlugokencky, Janusz Eluszkiewicz, Marc L. Fischer, Greet Janssens-Maenhout, Ben R. Miller, John B. Miller, Stephen A. Montzka, Thomas Nehrkorn, and Colm Sweeney, PNAS, 2013, doi: 10.1073/pnas.1314392110. [Full text]

Methane emissions estimate from airborne measurements over a western United States natural gas field – Karion et al. (2013) “Methane (CH4) emissions from natural gas production are not well quantified and have the potential to offset the climate benefits of natural gas over other fossil fuels. We use atmospheric measurements in a mass balance approach to estimate CH4 emissions of 55 ± 15 × 103 kg h−1 from a natural gas and oil production field in Uintah County, Utah, on 1 day: 3 February 2012. This emission rate corresponds to 6.2%–11.7% (1σ) of average hourly natural gas production in Uintah County in the month of February. This study demonstrates the mass balance technique as a valuable tool for estimating emissions from oil and gas production regions and illustrates the need for further atmospheric measurements to determine the representativeness of our single-day estimate and to better assess inventories of CH4 emissions.” Anna Karion, Colm Sweeney, Gabrielle Pétron, Gregory Frost, R. Michael Hardesty, Jonathan Kofler, Ben R. Miller, Tim Newberger, Sonja Wolter, Robert Banta, Alan Brewer, Ed Dlugokencky, Patricia Lang, Stephen A. Montzka, Russell Schnell, Pieter Tans, Michael Trainer, Robert Zamora, Stephen Conley, Geophysical Research Letters, Volume 40, Issue 16, pages 4393–4397, 28 August 2013, DOI: 10.1002/grl.50811.

Measurements of methane emissions at natural gas production sites in the United States – Allen et al. (2013) “Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confidence bounds of 0.67–3.3 Mg), compared with an average of 81 Mg per event in the 2011 EPA national emission inventory from April 2013. Emission factors for pneumatic pumps and controllers as well as equipment leaks were both comparable to and higher than estimates in the national inventory. Overall, if emission factors from this work for completion flowbacks, equipment leaks, and pneumatic pumps and controllers are assumed to be representative of national populations and are used to estimate national emissions, total annual emissions from these source categories are calculated to be 957 Gg of methane (with sampling and measurement uncertainties estimated at ±200 Gg). The estimate for comparable source categories in the EPA national inventory is ∼1,200 Gg. Additional measurements of unloadings and workovers are needed to produce national emission estimates for these source categories. The 957 Gg in emissions for completion flowbacks, pneumatics, and equipment leaks, coupled with EPA national inventory estimates for other categories, leads to an estimated 2,300 Gg of methane emissions from natural gas production (0.42% of gross gas production).” David T. Allen, Vincent M. Torres, James Thomas, David W. Sullivan, Matthew Harrison, Al Hendler, Scott C. Herndon, Charles E. Kolb, Matthew P. Fraser, A. Daniel Hill, Brian K. Lamb, Jennifer Miskimins, Robert F. Sawyer, and John H. Seinfeld, PNAS, 2013, vol. 110 no. 44, 17768–17773, doi: 10.1073/pnas.1304880110. [Full text]

Greater focus needed on methane leakage from natural gas infrastructure – Alvarez et al. (2012) “Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse gas emissions in the process. However, there has also been confusion about the climate implications of increased use of natural gas for electric power and transportation. We propose and illustrate the use of technology warming potentials as a robust and transparent way to compare the cumulative radiative forcing created by alternative technologies fueled by natural gas and oil or coal by using the best available estimates of greenhouse gas emissions from each fuel cycle (i.e., production, transportation and use). We find that a shift to compressed natural gas vehicles from gasoline or diesel vehicles leads to greater radiative forcing of the climate for 80 or 280 yr, respectively, before beginning to produce benefits. Compressed natural gas vehicles could produce climate benefits on all time frames if the well-to-wheels CH4 leakage were capped at a level 45–70% below current estimates. By contrast, using natural gas instead of coal for electric power plants can reduce radiative forcing immediately, and reducing CH4 losses from the production and transportation of natural gas would produce even greater benefits. There is a need for the natural gas industry and science community to help obtain better emissions data and for increased efforts to reduce methane leakage in order to minimize the climate footprint of natural gas.” Ramón A. Alvarez, Stephen W. Pacala, James J. Winebrake, William L. Chameides, and Steven P. Hamburg, PNAS, 2013, vol. 109 no. 17, 6435–6440, doi: 10.1073/pnas.1202407109. [Full text]

Hydrocarbon emissions characterization in the Colorado Front Range: A pilot study – Pétron et al. (2012) “The multispecies analysis of daily air samples collected at the NOAA Boulder Atmospheric Observatory (BAO) in Weld County in northeastern Colorado since 2007 shows highly correlated alkane enhancements caused by a regionally distributed mix of sources in the Denver-Julesburg Basin. To further characterize the emissions of methane and non-methane hydrocarbons (propane, n-butane, i-pentane, n-pentane and benzene) around BAO, a pilot study involving automobile-based surveys was carried out during the summer of 2008. A mix of venting emissions (leaks) of raw natural gas and flashing emissions from condensate storage tanks can explain the alkane ratios we observe in air masses impacted by oil and gas operations in northeastern Colorado. Using the WRAP Phase III inventory of total volatile organic compound (VOC) emissions from oil and gas exploration, production and processing, together with flashing and venting emission speciation profiles provided by State agencies or the oil and gas industry, we derive a range of bottom-up speciated emissions for Weld County in 2008. We use the observed ambient molar ratios and flashing and venting emissions data to calculate top-down scenarios for the amount of natural gas leaked to the atmosphere and the associated methane and non-methane emissions. Our analysis suggests that the emissions of the species we measured are most likely underestimated in current inventories and that the uncertainties attached to these estimates can be as high as a factor of two.” Gabrielle Pétron, Gregory Frost, Benjamin R. Miller, Adam I. Hirsch, Stephen A. Montzka, Anna Karion, Michael Trainer, Colm Sweeney, Arlyn E. Andrews, Lloyd Miller, Jonathan Kofler, Amnon Bar-Ilan, Ed J. Dlugokencky, Laura Patrick, Charles T. Moore Jr., Thomas B. Ryerson, Carolina Siso, William Kolodzey, Patricia M. Lang, Thomas Conway, Paul Novelli, Kenneth Masarie, Bradley Hall, Douglas Guenther, Duane Kitzis, John Miller, David Welsh, Dan Wolfe, William Neff, Pieter Tans, Journal of Geophysical Research: Atmospheres (1984–2012), Volume 117, Issue D4, 27 February 2012, DOI: 10.1029/2011JD016360. [Full text]

Venting and leaking of methane from shale gas development: response to Cathles et al. – Howarth et al. (2012) “In April 2011, we published the first comprehensive analysis of greenhouse gas (GHG) emissions from shale gas obtained by hydraulic fracturing, with a focus on methane emissions. Our analysis was challenged by Cathles et al. (2012). Here, we respond to those criticisms. We stand by our approach and findings. The latest EPA estimate for methane emissions from shale gas falls within the range of our estimates but not those of Cathles et al. which are substantially lower. Cathles et al. believe the focus should be just on electricity generation, and the global warming potential of methane should be considered only on a 100-year time scale. Our analysis covered both electricity (30% of US usage) and heat generation (the largest usage), and we evaluated both 20- and 100-year integrated time frames for methane. Both time frames are important, but the decadal scale is critical, given the urgent need to avoid climate-system tipping points. Using all available information and the latest climate science, we conclude that for most uses, the GHG footprint of shale gas is greater than that of other fossil fuels on time scales of up to 100 years. When used to generate electricity, the shale-gas footprint is still significantly greater than that of coal at decadal time scales but is less at the century scale. We reiterate our conclusion from our April 2011 paper that shale gas is not a suitable bridge fuel for the 21st Century.” Robert W. Howarth, Renee Santoro and Anthony Ingraffea, Climatic Change, DOI: 10.1007/s10584-012-0401-0. [Full text]

A commentary on “The greenhouse-gas footprint of natural gas in shale formations” by R.W. Howarth, R. Santoro, and Anthony Ingraffea – Cathles et al. (2012) “Natural gas is widely considered to be an environmentally cleaner fuel than coal because it does not produce detrimental by-products such as sulfur, mercury, ash and particulates and because it provides twice the energy per unit of weight with half the carbon footprint during combustion. These points are not in dispute. However, in their recent publication in Climatic Change Letters, Howarth et al. (2011) report that their life-cycle evaluation of shale gas drilling suggests that shale gas has a larger GHG footprint than coal and that this larger footprint “undercuts the logic of its use as a bridging fuel over the coming decades”. We argue here that their analysis is seriously flawed in that they significantly overestimate the fugitive emissions associated with unconventional gas extraction, undervalue the contribution of “green technologies” to reducing those emissions to a level approaching that of conventional gas, base their comparison between gas and coal on heat rather than electricity generation (almost the sole use of coal), and assume a time interval over which to compute the relative climate impact of gas compared to coal that does not capture the contrast between the long residence time of CO2 and the short residence time of methane in the atmosphere. High leakage rates, a short methane GWP, and comparison in terms of heat content are the inappropriate bases upon which Howarth et al. ground their claim that gas could be twice as bad as coal in its greenhouse impact. Using more reasonable leakage rates and bases of comparison, shale gas has a GHG footprint that is half and perhaps a third that of coal.” Lawrence M. Cathles, Larry Brown, Milton Taam and Andrew Hunter, Climatic Change, DOI: 10.1007/s10584-011-0333-0. [Full text]

Methane and the greenhouse-gas footprint of natural gas from shale formations – Howarth et al. (2011) “We evaluate the greenhouse gas footprint of natural gas obtained by high-volume hydraulic fracturing from shale formations, focusing on methane emissions. Natural gas is composed largely of methane, and 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the life-time of a well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following the fracturing. Methane is a powerful greenhouse gas, with a global warming potential that is far greater than that of carbon dioxide, particularly over the time horizon of the first few decades following emission. Methane contributes substantially to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The footprint for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years. Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years.” Robert W. Howarth, Renee Santoro and Anthony Ingraffea, Climatic Change, Volume 106, Number 4, 679-690, DOI: 10.1007/s10584-011-0061-5. [Full text]

Future development of the upstream greenhouse gas emissions from natural gas industry, focussing on Russian gas fields and export pipelines – Lechtenböhmer & Dienst (2010) “Natural gas makes an increasing contribution to the European Union’s energy supply. Due to its efficiency and low level of combustion emissions this reduces greenhouse gas emissions compared to the use of other fossil fuels. However, being itself a potent greenhouse gas, a high level of direct losses of natural gas in its process chain could neutralise these advantages. Which effect will finally prevail depends on future economical as well as technical developments. Based on two different scenarios of the main influencing factors we can conclude that over the next two decades CH4 emissions from the natural gas supply chain can be significantly reduced, in spite of unfavourable developments of the supply structures. This, however, needs a substantial, but economically attractive investment into new technology, particularly in Russia.” S. Lechtenböhmer, C. Dienst, Journal of Integrative Environmental Sciences, Volume 7, Issue S1, 2010, Pages 39 – 48, DOI: 10.1080/19438151003774463.

Study on Methane Emission Reduction Potential in China’s Oil and Natural Gas Industry – Liu et al. (2008) A review report of China’s situation with natural gas methane emissions. Junrong Liu and Jun Yao, Michael Gallaher and Jeff Coburn, Roger Fernandez, RTI Project Number 0208702.027, Prepared for U.S. EPA, April 2008. [Full text]

Tapping the leakages: Methane losses, mitigation options and policy issues for Russian long distance gas transmission pipelines – Lechtenböhmer et al. (2007) “The Russian natural gas industry is the world’s largest producer and transporter of natural gas. This paper aims to characterize the methane emissions from Russian natural gas transmission operations, to explain projects to reduce these emissions, and to characterize the role of emissions reduction within the context of current GHG policy. It draws on the most recent independent measurements at all parts of the Russian long distance transport system made by the Wuppertal Institute in 2003 and combines these results with the findings from the US Natural Gas STAR Program on GHG mitigation options and economics. With this background the paper concludes that the methane emissions from the Russian natural gas long distance network are approximately 0.6% of the natural gas delivered. Mitigating these emissions can create new revenue streams for the operator in the form of reduced costs, increased gas throughput and sales, and earned carbon credits. Specific emissions sources that have cost-effective mitigation solutions are also opportunities for outside investment for the Joint Implementation Kyoto Protocol flexibility mechanism or other carbon markets.” Stefan Lechtenböhmer, Carmen Dienst, Manfred Fischedick, Thomas Hanke, Roger Fernandez, Don Robinson, Ravi Kantamaneni and Brian Gillis, International Journal of Greenhouse Gas Control, Volume 1, Issue 4, October 2007, Pages 387-395, doi:10.1016/S1750-5836(07)00089-8.

Greenhouse gases: Low methane leakage from gas pipelines – Lelieveld et al. (2005) “Using natural gas for fuel releases less carbon dioxide per unit of energy produced than burning oil or coal, but its production and transport are accompanied by emissions of methane, which is a much more potent greenhouse gas than carbon dioxide in the short term. This calls into question whether climate forcing could be reduced by switching from coal and oil to natural gas1. We have made measurements in Russia along the world’s largest gas-transport system and find that methane leakage is in the region of 1.4%, which is considerably less than expected and comparable to that from systems in the United States. Our calculations indicate that using natural gas in preference to other fossil fuels could be useful in the short term for mitigating climate change.” J. Lelieveld, S. Lechtenböhmer, S. S. Assonov, C. A. M. Brenninkmeijer, C. Dienst, M. Fischedick & T. Hanke, Nature 434, 841-842 (14 April 2005) | doi:10.1038/434841a.

Estimate of methane emissions from the U.S. natural gas industry – Kirchgessner et al. (1997) “Global methane emissions from the fossil fuel industries have been poorly quantified and, in many cases, emissions are not well-known even at the country level. Historically, methane emissions from the U.S. gas industry have been based on sparse data, incorrect assumptions, or both. As a result, the estimate of the contribution these emissions make to the global methane inventory could be inaccurate. For this reason the assertion that global warming could be reduced by replacing coal and oil fuels with natural gas could not be defended. A recently completed, multi year study conducted by the U.S. Environmental Protection Agency’s Office of Research and Development and the Gas Research Institute had the objective of determining methane emissions from the U.S. gas industry with an accuracy of t 0.5% of production. The study concluded that, in the 1992 base year, methane emissions from the industry were 314 t 105 Bscf or 6.04 t 2.01 Tg (all conversions to international units are made at 15.56 °C and 101.325 kPa)” David A. Kirchgessner, Robert A. Lott, R. Michael Cowgill, Matthew R. Harrison and Theresa M. Shires, Chemosphere, Volume 35, Issue 6, September 1997, Pages 1365-1390, doi:10.1016/S0045-6535(97)00236-1. [Full text]

Methane emission measurements in urban areas in Eastern Germany – Shorter et al. (1996) “We have investigated methane emissions from urban sources in the former East Germany using innovative measurement techniques including a mobile real-time methane instrument and tracer release experiments. Anthropogenic and biogenic sources were studied with the emphasis on methane emissions from gas system sources, including urban distribution facilities and a production plant. Methane fluxes from pressure regulating stations ranged from 0.006 to 24. l/min. Emissions from diffuse sources in urban areas were also measured with concentration maps and whole city flux experiments. The area fluxes of the two towns studied were 0.37 and 1.9 g/m2/s. The emissions from individual gas system stations and total town emissions of this study are comparable to results of similar sites examined in the United States.” Joanne H. Shorter, J. Barry Mcmanus, Charles E. Kolb, Eugene J. Allwine, Brian K. Lamb, Byard W. Mosher, Robert C. Harriss, Uwe Partchatka, Horst Fischer and Geoffrey W. Harris, et al., Journal of Atmospheric Chemistry, Volume 24, Number 2, 121-140, DOI: 10.1007/BF00162407. [Full text]

Indirect chemical effects of methane on climate warming – Lelieveld & Crutzen (1992) “METHANE concentrations in the atmosphere have increased from about 0.75 to 1.7 p.p.m.v. since pre-industrial times1,2. The current annual rate of increase of about 0.8% yr-1 (ref. 2) is due to increases in industrial and agricultural emissions. This increase in atmospheric methane concentrations not only influences the climate directly, but also indirectly through chemical reactions. Here we show that the climate effects of methane’s atmospheric chemistry have previously been overestimated, notably by the Inter-governmental Panel on Climate Change (IPCC)3, largely owing to neglect of the height dependence of certain atmospheric radiative processes. Using available estimates of fossil-fuel-related leaks of methane, our results show that switching from coal and oil to natural gas as an energy source would reduce climate warming. A significant fraction of methane emissions cannot, however, be accounted for by known sources; should leakages from gas production and distribution be underestimated for some countries, then it might be unwise to switch to using natural gas.” Jos Lelieveld & Paul J. Crutzen, Nature 355, 339 – 342 (23 January 1992); doi:10.1038/355339a0.

Gas leakage in United Kingdom – Wallis (1992) No abstract. M. K. Wallis, Nature 359, 355 (01 October 1992); doi:10.1038/359355a0.

Leaking gas in the greenhouse – Wallis (1991) “Greenhouse gas emissions by the United Kingdom could be significantly reduced by replacement of old and leaking gas mains. Such a programme could even be cost-effective for the utility concerned.” Max K. Wallis, Nature 354, 428 (12 December 1991); doi:10.1038/354428a0.

Leaky answer to greenhouse gas? – Wallis (1990) No abstract. Max K. Wallis, Nature 344, 25 – 26 (01 March 1990).

A study of leakage from the UK natural gas distribution system – Mitchell et al. (1990) “This paper studies leakage from the UK natural gas distribution system. British Gas maintains that the leakage rate is around 1% of supply. This paper estimates a Low, Medium and High Case leakage rate of 1.9%, 5.3% and 10.8% respectively. The authors are confident that the leakage rate is above 1.9% and consider it more likely that the leakage rate is between the Medium and High Case. This investigation has been very cautious in that only leakage from the low pressure, medium pressure and service pipelines has been calculated. No estimates of leakage from the broader supply system have been included because of lack of verifiable information. The implications of these leakage rates for energy policy are considered.” Catherine Mitchell, Jim Sweet and Tim Jackson, Energy Policy, Volume 18, Issue 9, November 1990, Pages 809-818, doi:10.1016/0301-4215(90)90060-H.

Methane leakage from natural gas – Okken (1990) “Carbon dioxide (CO2) emissions from fossil fuels are a major cause of the global greenhouse effect. Fuel switching is one of the options to reduce emissions. However, CO2 is not the only greenhouse gas. This paper addresses the question whether greenhouse effect mitigating strategies such as fuel switching would change if methane (CH4) is taken into account, by calculating the global warming from current energy related CH4 and CO (carbon monoxide) emissions as ‘CO2 equivalents’.” P. A. Okken, Energy Policy, Volume 18, Issue 2, March 1990, Pages 202-204.

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Papers on geoengineering

Posted by Ari Jokimäki on March 31, 2011

This is a list of papers on geoengineering. Focus is on general papers on the subject. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

For lots and lots of additional papers, see Oxford Geoengineering Programme’s Reference Library.

Engineering geo-engineering – Fox & Chapman (2011) “This paper reviews the geo-engineering approach to tackling climate change. The failure of the 15th United Nations Framework Convention on Climate Change Conference of the Parties (COP15) to obtain a legally binding emissions reduction agreement makes the deployment of geo-engineering solutions an increasingly attractive proposition. This review looks at a variety of global and local approaches to geo-engineering covering solar radiation management and carbon cycle engineering and attempts to assess the feasibility of the technologies from an engineering perspective. However, despite the plethora of ideas generated by the science community, it still appears that much work remains to be done in the initial engineering assessment of these techniques and this is a major hurdle to overcome before any geo-engineering scheme can be fully considered. Hence, the paper concludes by calling for the instigation of national and international programmes of research at the feasibility level, to inform discussions regarding future possible deployment of small scale, local geo-engineering and adaptation measures.” Timothy A. Fox, Lee Chapman, Meteorological Applications, Volume 18, Issue 1, pages 1–8, March 2011. [Full text]

History of climate engineering – Bonnheim (2010) “The modern concept of geoengineering as a response to anthropogenic climate change evolved from much earlier proposals to modify the climate. The well-documented history of weather modification provides a much-needed historical perspective on geoengineering in the face of current climate anxiety and the need for responsive action. Drawing on material from the mid-20th century until today, this paper asserts the importance of looking at geoengineering holistically—of integrating social considerations with technical promise, and scientific study with human and moral dimensions. While the debate is often couched in scientific terms, the consequences of geoengineering the climate stretch far beyond the world of science into the realms of ethics, legality, and society. Studying the history of geoengineering can help produce fresh insights about what has happened and about what may happen, and can help frame important decisions that will soon be made as to whether geoengineering is a feasible alternative to mitigation, a possible partner, or a dangerous experiment with our fragile planet.” Noah Byron Bonnheim, Wiley Interdisciplinary Reviews: Climate Change, Volume 1, Issue 6, pages 891–897, November/December 2010, DOI: 10.1002/wcc.82.

The radiative forcing potential of different climate geoengineering options – Lenton & Vaughan (2009) “Climate geoengineering proposals seek to rectify the Earth’s current and potential future radiative imbalance, either by reducing the absorption of incoming solar (shortwave) radiation, or by removing CO2 from the atmosphere and transferring it to long-lived reservoirs, thus increasing outgoing longwave radiation. A fundamental criterion for evaluating geoengineering options is their climate cooling effectiveness, which we quantify here in terms of radiative forcing potential. We use a simple analytical approach, based on energy balance considerations and pulse response functions for the decay of CO2 perturbations. This aids transparency compared to calculations with complex numerical models, but is not intended to be definitive. It allows us to compare the relative effectiveness of a range of proposals. We consider geoengineering options as additional to large reductions in CO2 emissions. By 2050, some land carbon cycle geoengineering options could be of comparable magnitude to mitigation “wedges”, but only stratospheric aerosol injections, albedo enhancement of marine stratocumulus clouds, or sunshades in space have the potential to cool the climate back toward its pre-industrial state. Strong mitigation, combined with global-scale air capture and storage, afforestation, and bio-char production, i.e. enhanced CO2 sinks, might be able to bring CO2 back to its pre-industrial level by 2100, thus removing the need for other geoengineering. Alternatively, strong mitigation stabilising CO2 at 500 ppm, combined with geoengineered increases in the albedo of marine stratiform clouds, grasslands, croplands and human settlements might achieve a patchy cancellation of radiative forcing. Ocean fertilisation options are only worthwhile if sustained on a millennial timescale and phosphorus addition may have greater long-term potential than iron or nitrogen fertilisation. Enhancing ocean upwelling or downwelling have trivial effects on any meaningful timescale. Our approach provides a common framework for the evaluation of climate geoengineering proposals, and our results should help inform the prioritisation of further research into them.” Lenton, T. M. and Vaughan, N. E., Atmos. Chem. Phys., 9, 5539-5561, doi:10.5194/acp-9-5539-2009, 2009. [Full text]

A review of climate geoengineering proposals – Vaughan & Lenton (2009) “Climate geoengineering proposals seek to rectify the current radiative imbalance via either (1) reducing incoming solar radiation (solar radiation management) or (2) removing CO2 from the atmosphere and transferring it to long-lived reservoirs (carbon dioxide removal). For each option, we discuss its effectiveness and potential side effects, also considering lifetime of effect, development and deployment timescale, reversibility, and failure risks. We present a detailed review that builds on earlier work by including the most recent literature, and is more extensive than previous comparative frameworks. Solar radiation management propsals are most effective but short-lived, whilst carbon dioxide removal measures gain effectiveness the longer they are pursued. Solar radiation management could restore the global radiative balance, but must be maintained to avoid abrupt warming, meanwhile ocean acidification and residual regional climate changes would still occur. Carbon dioxide removal involves less risk, and offers a way to return to a pre-industrial CO2 level and climate on a millennial timescale, but is potentially limited by the CO2 storage capacity of geological reservoirs. Geoengineering could complement mitigation, but it is not an alternative to it. We expand on the possible combinations of mitigation, carbon dioxide removal and solar radiation management that might be used to avoid dangerous climate change.” Naomi E. Vaughan and Timothy M. Lenton, Climatic Change, DOI: 10.1007/s10584-011-0027-7.

Toward ethical norms and institutions for climate engineering research – Morrow et al. (2009) “Climate engineering (CE), the intentional modification of the climate in order to reduce the effects of increasing greenhouse gas concentrations, is sometimes touted as a potential response to climate change. Increasing interest in the topic has led to proposals for empirical tests of hypothesized CE techniques, which raise serious ethical concerns. We propose three ethical guidelines for CE researchers, derived from the ethics literature on research with human and animal subjects, applicable in the event that CE research progresses beyond computer modeling. The Principle of Respect requires that the scientific community secure the global public’s consent, voiced through their governmental representatives, before beginning any empirical research. The Principle of Beneficence and Justice requires that researchers strive for a favorable risk–benefit ratio and a fair distribution of risks and anticipated benefits, all while protecting the basic rights of affected individuals. Finally, the Minimization Principle requires that researchers minimize the extent and intensity of each experiment by ensuring that no experiments last longer, cover a greater geographical extent, or have a greater impact on the climate, ecosystem, or human welfare than is necessary to test the specific hypotheses in question. Field experiments that might affect humans or ecosystems in significant ways should not proceed until a full discussion of the ethics of CE research occurs and appropriate institutions for regulating such experiments are established.” David R Morrow et al 2009 Environ. Res. Lett. 4 045106 doi: 10.1088/1748-9326/4/4/045106. [Full text]

Ranking geo-engineering schemes – Boyd (2008) “Geo-engineering proposals for mitigating climate change continue to proliferate without being tested. It is time to select and assess the most promising ideas according to efficacy, cost, all aspects of risk and, importantly, their rate of mitigation. Propelling aerosols into the upper atmosphere or pumping carbon dioxide into the deep ocean are just two schemes that have been proposed to repair the Earth’s climate through geo-engineering (see Box 1). In the absence of adequate reductions in anthropogenic CO2 emissions, geo-engineering has been put forward as the only remaining option that might fix our rapidly changing climate.” Philip W. Boyd, Nature Geoscience 1, 722 – 724 (2008), doi:10.1038/ngeo348. [Full text]

The Incredible Economics of Geoengineering – Barrett (2008) “The focus of climate policy so far has been on reducing the accumulation of greenhouse gases. That approach, however, requires broad international cooperation and, being expensive, has been hindered by free riding; so far, little action has been taken. An alternative approach is to counteract climate change by reducing the amount of solar radiation that strikes the Earth—“geoengineering.” In contrast to emission reductions, this approach is inexpensive and can be undertaken by a single country, unilaterally. But geoengineering also has worrying consequences: it may harm some countries; it would not address ocean acidification; it would pose new risks. The fundamental challenge posed by this new technology is not free riding but governance: who should decide if and under what circumstances geoengineering should be used?” Scott Barrett, Environmental and Resource Economics, Volume 39, Number 1, 45-54, DOI: 10.1007/s10640-007-9174-8. [Full text]

Geoengineering: could we or should we make it work? – Schneider (2008) “Schemes to modify large-scale environment systems or control climate have been proposed for over 50 years to (i) increase temperatures in high latitudes, (ii) increase precipitation, (iii) decrease sea ice, (iv) create irrigation opportunities, or (v) offset potential global warming by injecting iron in the oceans or sea-salt aerosol in the marine boundary layer or spreading dust in the stratosphere to reflect away an amount of solar energy equivalent to the amount of heat trapped by increased greenhouse gases from human activities. These and other proposed geoengineering schemes are briefly reviewed. Recent schemes to intentionally modify climate have been proposed as either cheaper methods to counteract inadvertent climatic modifications than conventional mitigation techniques such as carbon taxes or pollutant emissions regulations or as a counter to rising emissions as governments delay policy action. Whereas proponents argue cost-effectiveness or the need to be prepared if mitigation and adaptation policies are not strong enough or enacted quickly enough to avoid the worst widespread impacts, critics point to the uncertainty that (i) any geoengineering scheme would work as planned or (ii) that the many centuries of international political stability and cooperation needed for the continuous maintenance of such schemes to offset century-long inadvertent effects is socially feasible. Moreover, the potential exists for transboundary conflicts should negative climatic events occur during geoengineering activities.” Stephen H Schneider, Phil. Trans. R. Soc. A 13 November 2008 vol. 366 no. 1882 3843-3862, doi: 10.1098/rsta.2008.0145. [Full text]

A geophysiologist’s thoughts on geoengineering – Lovelock (2008) “The Earth is now recognized as a self-regulating system that includes a reactive biosphere; the system maintains a long-term steady-state climate and surface chemical composition favourable for life. We are perturbing the steady state by changing the land surface from mainly forests to farm land and by adding greenhouse gases and aerosol pollutants to the air. We appear to have exceeded the natural capacity to counter our perturbation and consequently the system is changing to a new and as yet unknown but probably adverse state. I suggest here that we regard the Earth as a physiological system and consider amelioration techniques, geoengineering, as comparable to nineteenth century medicine.” James Lovelock, Phil. Trans. R. Soc. A 13 November 2008 vol. 366 no. 1882 3883-3890, doi: 10.1098/rsta.2008.0135. [Full text]

Geoengineering: Encouraging Research and Overseeing Implementation – Cicerone (2006) No abstract Ralph J. Cicerone, Climatic Change, Volume 77, Numbers 3-4, 221-226, DOI: 10.1007/s10584-006-9102-x. [Full text]

The pathological history of weather and climate modification: Three cycles of promise and hype – Fleming (2006) No abstract.” James Rodger Fleming, Historical Studies in the Physical and Biological Sciences, 2006, Vol. 37, Number 1, pps 3-25. [Full text]

Geoengineering the Climate: History and Prospect – Keith (2000) “Geoengineering is the intentional large-scale manipulation of the environment, particularly manipulation that is intended to reduce undesired anthropogenic climate change. The post-war rise of climate and weather modification and the history of U.S. assessments of the CO2-climate problem is reviewed. Proposals to engineer the climate are shown to be an integral element of this history. Climate engineering is reviewed with an emphasis on recent developments, including low-mass space-based scattering systems for altering the planetary albedo, simulation of the climate’s response to albedo modification, and new findings on iron fertilization in oceanic ecosystems. There is a continuum of human responses to the climate problem that vary in resemblance to hard geoengineering schemes such as space-based mirrors. The distinction between geoengineering and mitigation is therefore fuzzy. A definition is advanced that clarifies the distinction between geoengineering and industrial carbon management. Assessment of geoengineering is reviewed under various framings including economics, risk, politics, and environmental ethics. Finally, arguments are presented for the importance of explicit debate about the implications of countervailing measures such as geoengineering.” David W. Keith, Annual Review of Energy and the Environment, Vol. 25: 245-284 (Volume publication date November 2000), DOI: 10.1146/annurev.energy.25.1.245. [Full text]

Earth systems engineering and management – Schneider (2001) “Imagine that we could let the world’s economy continue to grow, bring the disadvantaged classes up from poverty and at the same time not threaten the atmosphere or global ecosystems with unprecedented build-up of greenhouse gases and the projected climatic risks of such growth. Earth systems engineering and management may just be such a panacea, some have suggested. But could we anticipate the costs or ever truly predict the consequences?” Stephen H. Schneider, Nature 409, 417-421 (18 January 2001) | doi:10.1038/35053203. [Full text]

Geoengineering Earth’s radiation balance to mitigate CO2‐induced climate change – Govindasamy & Caldeira (2000) “To counteract anthropogenic climate change, several schemes have been proposed to diminish solar radiation incident on Earth’s surface. These geoengineering schemes could reverse global annual mean warming; however, it is unclear to what extent they would mitigate regional and seasonal climate change, because radiative forcing from greenhouse gases such as CO2 differs from that of sunlight. No previous study has directly addressed this issue. In the NCAR CCM3 atmospheric general circulation model, we reduced the solar luminosity to balance the increased radiative forcing from doubling atmospheric CO2. Our results indicate that geoengineering schemes could markedly diminish regional and seasonal climate change from increased atmospheric CO2, despite differences in radiative forcing patterns. Nevertheless, geoengineering schemes could prove environmentally risky.” Govindasamy, B., and K. Caldeira (2000), Geophys. Res. Lett., 27(14), 2141–2144, doi:10.1029/1999GL006086. [Full text]

The economic diplomacy of geoengineering – Schelling (1996) “‘Geoengineering’ is a new term, still seeking a definition. It seems to imply something global, intentional, and unnatural. For the radiation balance, geoengineering may be fifty years in the future; today’s means may be out of date then, and the future means are not yet known. It might immensely simplify greenhouse policy, transforming it from an exceedingly complicated regulatory regime to a problem in international cost sharing, a problem that we are familiar with. Putting things in the stratosphere or in orbit can probably be done by exo-national programs, not depending on the behavior of populations, not requiring national regulations or incentives, not dependent on universal participation. It will involve merely deciding what to do, how much to do, and who is to pay for it.” Thomas C. Schelling, Climatic Change, Volume 33, Number 3, 303-307, DOI: 10.1007/BF00142578.

May we engineer the climate? – Bodansky (1996) “Not only is the science of climate engineering uncertain; the legal issues are also highly uncertain. Although existing international law does not specifically limit the freedom of states to undertake climate engineering, the international community would likely demand a say should climate engineering move from the realm of speculation to concrete proposals. The experience of other environmental regimes, however, suggests that developing an international decision-making mechanism would be difficult, and that the international community might opt for a simple prohibition on climate engineering on grounds of ‘precaution’.” Daniel Bodansky, Climatic Change, Volume 33, Number 3, 309-321, DOI: 10.1007/BF00142579.

Geoengineering: Could— or should— we do it? – Schneider (1996) “Schemes to modify large-scale environment systems or to control climate have been seriously proposed for over 50 years, some to (1) increase temperatures in high latitudes, (2) increase precipitation, (3) decrease sea ice, (4) create irrigation opportunities or to offset potential global warming by spreading dust in the stratosphere to reflect away an equivalent amount of solar energy. These and other proposed geoengineering schemes are briefly reviewed from a historical perspective. More recently, many such schemes to advertently modify climate have been proposed as cheaper methods to counteract inadvertent climatic modifications than conventional mitigation techniques such as carbon taxes or pollutant emissions regulations. Whereas proponents argue cost effectiveness, critics of geoengineering argue that there is too much uncertainty to either (1) be confident that any geoengineering scheme would work as planned, or (2) that the many decades of international political stability and cooperation needed for the continuous maintenance of such schemes to offset century long inadvertent efforts is problematic. Moreover, there is potential for transboundary conflicts should negative climatic events occur during geoengineering activities since, given all the large uncertainties, it could not be assured to victims of such events that the schemes were entirely unrelated to their damages. Nevertheless, although I believe it would be irresponsible to implement any large-scale geoengineering scheme until scientific, legal and management uncertainties are substantially narrowed, I do agree that, given the potential for large inadvertent climatic changes now being built into the earth system, more systematic study of the potential for geoengineering is probably needed.” Stephen H. Schneider, Climatic Change, Volume 33, Number 3, 291-302, DOI: 10.1007/BF00142577.

Ethics and intentional climate change – Jamieson (1996) “In recent years the idea of geoengineering climate has begun to attract increasing attention. Although there was some discussion of manipulating regional climates throughout the 1970s and 1980s, the discussion was largely dormant. What has reawakened the conversation is the possibility that Earth may be undergoing a greenhouse-induced global warming, and the paucity of serious measures that have been taken to prevent it. In this paper I assess the ethical acceptability of ICC, based on my impressions of the conversation that is now taking place. Rather than offering a dispassionate analysis, I argue for a point of view. I propose a set of conditions that must be satisfied for an ICC project to be morally permissible and conclude that these conditions are not now satisfied. However, research on ICC should go forward so long as certain other conditions are met. I do not intend this to be the last word on the subject, but rather the first word. My hope is that others will be stimulated to think through the ethics of ICC.” Dale Jamieson, Climatic Change, Volume 33, Number 3, 323-336, DOI: 10.1007/BF00142580. [Full text]

Geoengineering the climate – MacCracken (1991) “Although much can be done to limit greenhouse gas emissions by conservation, improvements in efficiency, and use of alternative technologies, the use of fossil fuels at rates even sharply reduced from US per capita values will lead to rapidly increasing global concentrations of greenhouse gases. The available alternatives then become adapting to the changes, switching to alternative energy sources (e.g., solar, nuclear), or actively taking control of atmospheric composition and/or the climate. This note reviews options for geoengineering the climate.” MacCracken, M.C., UCRL-JC-108014. Lawrence Livermore National Laboratory, June 1991. [Full text]

Climate Stabilization: For Better or for Worse? – Kellogg & Schneider (1974) “Even if we could predict the future of our climate, climate control would be a hazardous venture.” W. W. Kellogg; S. H. Schneider, Science, New Series, Vol. 186, No. 4170. (Dec. 27, 1974), pp. 1163-1172. [Full text]

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Papers on global potential of bio-energy

Posted by Ari Jokimäki on December 2, 2010

This is a list of papers on the global potential of bio-energy. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

The global technical potential of bio-energy in 2050 considering sustainability constraints – Haberl et al. (2010) “Bio-energy, that is, energy produced from organic non-fossil material of biological origin, is promoted as a substitute for non-renewable (e.g., fossil) energy to reduce greenhouse gas (GHG) emissions and dependency on energy imports. At present, global bio-energy use amounts to approximately 50 EJ/yr, about 10% of humanity’s primary energy supply. We here review recent literature on the amount of bio-energy that could be supplied globally in 2050, given current expectations on technology, food demand and environmental targets (‘technical potential’). Recent studies span a large range of global bio-energy potentials from ≈30 to over 1000 EJ/yr. In our opinion, the high end of the range is implausible because of (1) overestimation of the area available for bio-energy crops due to insufficient consideration of constraints (e.g., area for food, feed or nature conservation) and (2) too high yield expectations resulting from extrapolation of plot-based studies to large, less productive areas. According to this review, the global technical primary bio-energy potential in 2050 is in the range of 160–270 EJ/yr if sustainability criteria are considered. The potential of bio-energy crops is at the lower end of previously published ranges, while residues from food production and forestry could provide significant amounts of energy based on an integrated optimization (‘cascade utilization’) of biomass flows.” Helmut Haberl, Tim Beringer, Sribas C Bhattacharya, Karl-Heinz Erb and Monique Hoogwijk, Current Opinion in Environmental Sustainability, 2010, doi:10.1016/j.cosust.2010.10.007.

Bioenergy potentials from forestry in 2050 An assessment of the drivers that determine the potentials – Smeets & Faaij (2007) “The purpose of this study was to evaluate the global energy production potential of woody biomass from forestry for the year 2050 using a bottom-up analysis of key factors. Woody biomass from forestry was defined as all of the aboveground woody biomass of trees, including all products made from woody biomass. This includes the harvesting, processing and use of woody biomass. The projection was performed by comparing the future demand with the future supply of wood, based on existing databases, scenarios, and outlook studies. Specific attention was paid to the impact of the underlying factors that determine this potential and to the gaps and uncertainties in our current knowledge. Key variables included the demand for industrial roundwood and woodfuel, the plantation establishment rates, and the various theoretical, technical, economical, and ecological limitations related to the supply of wood from forests. Forests, as defined in this study, exclude forest plantations. Key uncertainties were the supply of wood from trees outside forests, the future rates of deforestation, the consumption of woodfuel, and the theoretical, technical, economical, or ecological wood production potentials of the forests. Based on a medium demand and medium plantation scenario, the global theoretical potential of the surplus wood supply (i.e., after the demand for woodfuel and industrial roundwood is met) in 2050 was calculated to be 6.1 Gm3 (71 EJ) and the technical potential to be 5.5 Gm3 (64 EJ). In practice, economical considerations further reduced the surplus wood supply from forests to 1.3 Gm3 year-1 (15 EJ year−1). When ecological criteria were also included, the demand for woodfuel and industrial roundwood exceeded the supply by 0.7 Gm3 year-1 (8 EJ year-1). The bioenergy potential from logging and processing residues and waste was estimated to be equivalent to 2.4 Gm3 year-1 (28 EJ year-1) wood, based on a medium demand scenario. These results indicate that forests can, in theory, become a major source of bioenergy, and that the use of this bioenergy can, in theory, be realized without endangering the supply of industrial roundwood and woodfuel and without further deforestation. Regional shortages in the supply of industrial roundwood and woodfuel can, however, occur in some regions, e.g., South Asia and the Middle East and North Africa.” Edward M. W. Smeets and André P. C. Faaij, Climatic Change, Volume 81, Numbers 3-4, 353-390, DOI: 10.1007/s10584-006-9163-x. [Full text]

A bottom-up assessment and review of global bio-energy potentials to 2050 – Smeets et al. (2007) “In this article, a model for estimating bioenergy production potentials in 2050, called the Quickscan model, is presented. In addition, a review of existing studies is carried out, using results from the Quickscan model as a starting point. The Quickscan model uses a bottom-up approach and its development is based on an evaluation of data and studies on relevant factors such as population growth, per capita food consumption and the efficiency of food production. Three types of biomass energy sources are included: dedicated bioenergy crops, agricultural and forestry residues and waste, and forest growth. The bioenergy potential in a region is limited by various factors, such as the demand for food, industrial roundwood, traditional woodfuel, and the need to maintain existing forests for the protection of biodiversity. Special attention is given to the technical potential to reduce the area of land needed for food production by increasing the efficiency of food production. Thus, only the surplus area of agricultural land is included as a source for bioenergy crop production. A reference scenario was composed to analyze the demand for food. Four levels of advancement of agricultural technology in the year 2050 were assumed that vary with respect to the efficiency of food production. Results indicated that the application of very efficient agricultural systems combined with the geographic optimization of land use patterns could reduce the area of land needed to cover the global food demand in 2050 by as much as 72% of the present area. A key factor was the area of land suitable for crop production, but that is presently used for permanent grazing. Another key factor is the efficiency of the production of animal products. The bioenergy potential on surplus agricultural land (i.e. land not needed for the production of food and feed) equaled 215–1272 EJ yr−1, depending on the level of advancement of agricultural technology. The bulk of this potential is found in South America and Caribbean (47–221 EJ yr−1), sub-Saharan Africa (31–317 EJ yr−1) and the C.I.S. and Baltic States (45–199 EJ yr−1). Also Oceania and North America had considerable potentials: 20–174 and 38–102 EJ yr−1, respectively. However, realization of these (technical) potentials requires significant increases in the efficiency of food production, whereby the most robust potential is found in the C.I.S. and Baltic States and East Europe. Existing scenario studies indicated that such increases in productivity may be unrealistically high, although these studies generally excluded the impact of large scale bioenergy crop production. The global potential of bioenergy production from agricultural and forestry residues and wastes was calculated to be 76–96 EJ yr−1 in the year 2050. The potential of bioenergy production from surplus forest growth (forest growth not required for the production of industrial roundwood and traditional woodfuel) was calculated to be 74 EJ yr−1 in the year 2050.” Edward M.W. Smeets, André P.C. Faaij, Iris M. Lewandowski and Wim C. Turkenburg, Progress in Energy and Combustion Science, Volume 33, Issue 1, February 2007, Pages 56-106, doi:10.1016/j.pecs.2006.08.001.

Global Biomass Energy Potential – Moreira (2006) “The intensive use of renewable energy is one of the options to stabilize CO2atmospheric concentration at levels of 350 to 550ppm. A recent evaluation of the global potential of primary renewable energy carried out by Intergovernmental Panel on Climate Change (IPCC) sets a value of at least 2800EJ/yr, which is more than the most energy-intensive SRES scenario forecast for the world energy requirement up to the year 2100. Nevertheless, what is really important to quantify is the amount of final energy since the use of renewable sources may involve conversion efficiencies, from primary to final energy, different from the ones of conventional energy sources. In reality, IPCC does not provide a complete account of the final energy from renewables, but the text claims that using several available options to mitigate climate change, and renewables is only one of them, it is possible to stabilize atmospheric carbon dioxide (CO2) concentration at a low level. In this paper, we evaluate in detail biomass primary and final energy using sugarcane crop as a proxy, since it is one of the highest energy density forms of biomass, and through afforestation/reforestation using a model presented in IPCC Second Assessment Report (SAR). The conclusion is that the primary-energy potential for biomass has been under-evaluated by many authors and by IPCC, and this under-evaluation is even larger for final energy since sugarcane allows co-production of electricity and liquid fuel. Regarding forests we reproduce IPCC results for primary energy and calculate final energy. Sugarcane is a tropical crop and cannot be grown in all the land area forecasted for biomass energy plantation in the IPCC/TAR evaluation (i.e. 1280Mha). Nevertheless, there are large expanses of unexploited land, mainly in Latin America and Africa that are subject to warm weather and convenient rainfall. With the use of 143Mha of these lands it is possible to produce 164EJ/yr (1147GJ/hayr or 3.6W/m2on average) of primary energy and 90EJ/yr of final energy in the form of liquid fuel (alcohol) and electricity, using agricultural productivities near the best ones already achievable and biomass gasification technology. More remarkable is that these results can be obtained with the operation of 4,000 production units with unitary capacity similar to the largest currently in operation. These units should be spread over the tropical land area yielding a plantation density similar to the one presently observed in the state of São Paulo, Brazil, where alcohol and electricity have been commercialized in a cost-effective way for several years. Such an amount of final energy would be sufficiently large to fulfill all the expected global increase in oil demand, as well as in electricity consumption by 2030, assuming the energy demand of such sources continues to grow at the same pace observed over the last two decades. When sugarcane crops are combined with afforestation/reforestation it is possible to show that carbon emissions decline for some IPCC SRES scenarios by 2030, 2040 and 2050. Such energy alternatives significantly reduce CO2emissions by displacing fossil fuels and promote sustainable development through the creation of millions of direct and indirect jobs. Also, it opens an opportunity for negative CO2emissions when coupled with carbon dioxide capture and storage.” José Roberto Moreira, Mitigation and Adaptation Strategies for Global Change, Volume 11, Number 2, 313-333, DOI: 10.1007/s11027-005-9003-8.

Potential of biomass energy out to 2100, for four IPCC SRES land-use scenarios – Hoogwijk et al. (2005) “The availability of the resources is an important factor for high shares of biomass to penetrate the electricity, heat or liquid fuel markets. We have analysed the geographical and technical potential of energy crops for the years 2050–2100 for three land-use categories: abandoned agricultural land, low-productivity land and ‘rest land’, i.e. remaining no-productive land. We envisaged development paths using four scenarios resulting from different future land-use patterns that were developed by the Intergovernmental Panel on Climate Change in its Special Report on Emission Scenarios: A1, A2, B1 and B2. The geographical potential is defined as the product of the available area for energy crops and the corresponding productivity level for energy crops. The geographical potential of abandoned agricultural land is the largest contributor. For the year 2050 the geographical potential of abandoned land ranges from about 130 to 410 EJ yr−1. For the year 2100 it ranges from 240 to 850 EJ yr−1. The potential of low-productive land is negligible compared to the other categories. The rest land area is assumed to be partly available, resulting in ranges of the geographical potential from about 35 to 245 EJ yr−1 for the year 2050 and from about 35 to 265 EJ yr−1 in 2100. At a regional level, significant potentials are found in the Former USSR, East Asia and South America. The geographical potential can be converted to transportation fuels or electricity resulting in ranges of the technical potential for fuels in the year 2050 and 2100 equal to several times the present oil consumption.” Monique Hoogwijk, André Faaij, Bas Eickhout, Bert de Vries and Wim Turkenburg, Biomass and Bioenergy, Volume 29, Issue 4, October 2005, Pages 225-257, doi:10.1016/j.biombioe.2005.05.002.

Exploration of the ranges of the global potential of biomass for energy – Hoogwijk et al. (2003) “This study explores the range of future world potential of biomass for energy. The focus has been put on the factors that influence the potential biomass availability for energy purposes rather than give exact numbers. Six biomass resource categories for energy are identified: energy crops on surplus cropland, energy crops on degraded land, agricultural residues, forest residues, animal manure and organic wastes. Furthermore, specific attention is paid to the competing biomass use for material. The analysis makes use of a wide variety of existing studies on all separate categories. The main conclusion of the study is that the range of the global potential of primary biomass (in about 50 years) is very broad quantified at 33−1135 EJy−1. Energy crops from surplus agricultural land have the largest potential contribution (0–988 EJy−1). Crucial factors determining biomass availability for energy are: (1) The future demand for food, determined by the population growth and the future diet; (2) The type of food production systems that can be adopted world-wide over the next 50 years; (3) Productivity of forest and energy crops; (4) The (increased) use of bio-materials; (5) Availability of degraded land; (6) Competing land use types, e.g. surplus agricultural land used for reforestation. It is therefore not “a given” that biomass for energy can become available at a large-scale. Furthermore, it is shown that policies aiming for the energy supply from biomass should take the factors like food production system developments into account in comprehensive development schemes.” Monique Hoogwijk, André Faaij, Richard van den Broek, Göran Berndes, Dolf Gielen, and Wim Turkenburg, Biomass and Bioenergy, Volume 25, Issue 2, August 2003, Pages 119-133, doi:10.1016/S0961-9534(02)00191-5.

The contribution of biomass in the future global energy supply: a review of 17 studies – Berndes et al. (2003) “This paper discusses the contribution of biomass in the future global energy supply. The discussion is based on a review of 17 earlier studies on the subject. These studies have arrived at widely different conclusions about the possible contribution of biomass in the future global energy supply (e.g., from below 100 EJ yr−1 to above 400 EJ yr−1 in 2050). The major reason for the differences is that the two most crucial parameters—land availability and yield levels in energy crop production—are very uncertain, and subject to widely different opinions (e.g., the assessed 2050 plantation supply ranges from below 50 EJ yr−1 to almost 240 EJ yr−1). However, also the expectations about future availability of forest wood and of residues from agriculture and forestry vary substantially among the studies. The question how an expanding bioenergy sector would interact with other land uses, such as food production, biodiversity, soil and nature conservation, and carbon sequestration has been insufficiently analyzed in the studies. It is therefore difficult to establish to what extent bioenergy is an attractive option for climate change mitigation in the energy sector. A refined modeling of interactions between different uses and bioenergy, food and materials production—i.e., of competition for resources, and of synergies between different uses—would facilitate an improved understanding of the prospects for large-scale bioenergy and of future land-use and biomass management in general” Göran Berndes, Monique Hoogwijk, and Richard van den Broek, Biomass and Bioenergy, Volume 25, Issue 1, July 2003, Pages 1-28, doi:10.1016/S0961-9534(02)00185-X. [Full text]

Global bioenergy potentials through 2050 – Fischer & Schrattenholzer (2001) “This study explores the range of future world potential of biomass for energy. The focus has been put on the factors that influence the potential biomass availability for energy purposes rather than give exact numbers. Six biomass resource categories for energy are identified: energy crops on surplus cropland, energy crops on degraded land, agricultural residues, forest residues, animal manure and organic wastes. Furthermore, specific attention is paid to the competing biomass use for material. The analysis makes use of a wide variety of existing studies on all separate categories. The main conclusion of the study is that the range of the global potential of primary biomass (in about 50 years) is very broad quantified at 33−1135 EJy−1. Energy crops from surplus agricultural land have the largest potential contribution (0–988 EJy−1). Crucial factors determining biomass availability for energy are: (1) The future demand for food, determined by the population growth and the future diet; (2) The type of food production systems that can be adopted world-wide over the next 50 years; (3) Productivity of forest and energy crops; (4) The (increased) use of bio-materials; (5) Availability of degraded land; (6) Competing land use types, e.g. surplus agricultural land used for reforestation. It is therefore not “a given” that biomass for energy can become available at a large-scale. Furthermore, it is shown that policies aiming for the energy supply from biomass should take the factors like food production system developments into account in comprehensive development schemes.” Günther Fischer and Leo Schrattenholzer, Biomass and Bioenergy, Volume 20, Issue 3, March 2001, Pages 151-159, doi:10.1016/S0961-9534(00)00074-X. [Full text]

Evaluation of bioenergy potential with a multi-regional global-land-use-and-energy model – Yamamoto et al. (2001) “The purpose of this study is to evaluate the global bioenergy potential in the future using a multi-regional global-land-use-and-energy model (GLUE-11). The model covers a wide range of biomass flow including food chains from feed to meat, paper recycling, and discharge of biomass residues.

Through a set of simulations, the following results are obtained. (1) Supply potential of energy crops produced from surplus arable land will be available in North America, Western Europe, Oceania, Latin America, former USSR and Eastern Europe. However, the potential of energy crops will be strongly affected by the variation of parameters of food supply and demand such as animal food demand. (2) Bioenergy supply potential of biomass residues will be stable against a change of a food demand parameter. The ultimate bioenergy supply potential of biomass residues will be 265 EJ/year in the world in 2100. The practical potential of biomass residues in the world will be 114 EJ/year, which is equivalent to one-third of the commercial energy consumption in the world in 1990. (3) Concerning land uses, the global mature forest area will decrease by 24% between 1990 and 2100, because of growth of both population and wood biomass demand per capita in the developing regions. The mature forest, especially, will disappear by 2100 in some developing regions, such as Centrally Planned Asia, Middle East and North Africa, and South Asia.” Hiromi Yamamoto, Junichi Fujino and Kenji Yamaji, Biomass and Bioenergy, Volume 21, Issue 3, March 2001, Pages 185-203, doi:10.1016/S0961-9534(01)00025-3. [Full text]

The land cover and carbon cycle consequences of large-scale utilizations of biomass as an energy source – Leemans et al. (1996) “The use of modern biomass for energy generation has been considered in many studies as a possible measure for reducing or stabilizing global carbon dioxide (CO2) emissions. In this paper we assess the impacts of large-scale global utilization of biomass on regional and grid scale land cover, greenhouse gas emissions, and carbon cycle. We have implemented in the global environmental change model IMAGE the LESS biomass intensive scenario, which was developed for the Second Assessment Report of IPCC. This scenario illustrates the potential for reducing energy related emission by different sets of fuel mixes and a higher energy efficiency. Our analysis especially covers different consequences involved with such modern biomass scenarios. We emphasize influences of CO2 concentrations and climate change on biomass crop yield, land use, competition between food and biomass crops, and the different interregional trade patterns for modern biomass based energy. Our simulations show that the original LESS scenario is rather optimistic on the land requirements for large-scale biomass plantations. Our simulations show that 797 Mha is required while the original LESS scenario is based on 550 Mha. Such expansion of agricultural land will influence deforestation patterns and have significant consequenses for environmental issues, such as biodiversity. Altering modern biomass requirements and the locations where they are grown in the scenario shows that the outcome is sensitive for regional emissions and feedbacks in the C cycle and that competition between food and modern biomass can be significant. We conclude that the cultivation of large quantities of modern biomass is feasible, but that its effectiveness to reduce emissions of greenhouse gases has to be evaluated in combination with many other environmental land use and socio-economic factors.” Rik Leemans, André van Amstel, Coos Battjes, Eric Kreileman and Sander Toet, Global Environmental Change, Volume 6, Issue 4, September 1996, Pages 335-357, doi:10.1016/S0959-3780(96)00028-3.

World potential of renewable energies. Actually accessible in the nineties and environmental impact analysis. – Dessus et al. (1992) “Large scale application of renewable energies is a major challenge for sustainable development and greenhouse gas emission control. Theoretical potential of those various energies may seem unlimited. In fact a reasonable evaluation taking into account economically available technologies and local considerations make it possible to define annual energy amounts relevant for each technology. Diversely distributed around the world but nowhere missing, renewable energies have an important annual potential since the nineties. They could indeed contribute to some 40% of the nowadays world energy consumption, mainly from wood, waste and hydro, but also from solar and wind energy.” Dessus, B, Devin, B, Pharabod, F, Houille blanche. Grenoble [HOUILLE BLANCHE.]. no. 1, pp. 21-70. 1992.

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