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New research – atmospheric and oceanic circulation (August 10, 2016)

Posted by Ari Jokimäki on August 10, 2016

Some of the latest papers on atmospheric and oceanic circulation are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


The North Atlantic Oscillation as a driver of rapid climate change in the Northern Hemisphere (Delworth et al. 2016)

Abstract: Pronounced climate changes have occurred since the 1970s, including rapid loss of Arctic sea ice, large-scale warming and increased tropical storm activity in the Atlantic. Anthropogenic radiative forcing is likely to have played a major role in these changes, but the relative influence of anthropogenic forcing and natural variability is not well established. The above changes have also occurred during a period in which the North Atlantic Oscillation has shown marked multidecadal variations. Here we investigate the role of the North Atlantic Oscillation in these rapid changes through its influence on the Atlantic meridional overturning circulation and ocean heat transport. We use climate models to show that observed multidecadal variations of the North Atlantic Oscillation can induce multidecadal variations in the Atlantic meridional overturning circulation and poleward ocean heat transport in the Atlantic, extending to the Arctic. Our results suggest that these variations have contributed to the rapid loss of Arctic sea ice, Northern Hemisphere warming, and changing Atlantic tropical storm activity, especially in the late 1990s and early 2000s. These multidecadal variations are superimposed on long-term anthropogenic forcing trends that are the dominant factor in long-term Arctic sea ice loss and hemispheric warming.

Evidence of global warming impact on the evolution of the Hadley Circulation in ECMWF centennial reanalyses (D’Agostino & Lionello, 2016)

Abstract: This study analyzes the evolution of the Hadley Circulation (HC) during the twentieth century in ERA-20CM (AMIP-experiment) and ERA-20C (reanalysis). These two recent ECMWF products provide the opportunity for a new analysis of the HC trends and of their uncertainties. Further, the effect of sea surface temperature forcing (including its uncertainty) and data assimilation are investigated. Also the ECMWF reanalysis ERA-Interim, for the period 1979–2010, is considered for a complementary analysis. Datasets present important differences in characteristics and trends of the HC. In ERA-20C HC is weaker (especially the Southern Hemisphere HC) and the whole Northern Hemisphere HC is located more southward than in ERA-20CM (especially in the boreal summer). In ERA-Interim HC is stronger and wider than both other simulations. In general, the magnitude of trends is larger and more statistically significant in ERA-20C than in ERA-20CM. The presence of large multidecadal variability across twentieth century raises doubts on the interpretation of recent behavior, such as the onset of sustained long term trends, particularly for the HC strength. In spite of this, the southward shift of the Southern Edge and widening of the Southern Hemisphere HC appear robust features in all datasets, and their trends have accelerated in the last three decades, but actual expansion rates remain affected by considerable uncertainty. Inconsistencies between datasets are attributed to the different reproduction of the links between the HC width and factors affecting it (such as mean global temperature, tropopause height, meridional temperature contrast and planetary waves), which appear more robust in ERA-20CM than in ERA-20C, particularly for the two latter factors. Further, in ERA-Interim these correlations are not statistically significant. These outcomes suggest that data assimilation degrades the links between the HC and features influencing its dynamics.

Impact of slowdown of Atlantic overturning circulation on heat and freshwater transports (Kelly et al. 2016)

Abstract: Recent measurements of the strength of the Atlantic overturning circulation at 26°N show a 1 year drop and partial recovery amid a gradual weakening. To examine the extent and impact of the slowdown on basin wide heat and freshwater transports for 2004–2012, a box model that assimilates hydrographic and satellite observations is used to estimate heat transport and freshwater convergence as residuals of the heat and freshwater budgets. Using an independent transport estimate, convergences are converted to transports, which show a high level of spatial coherence. The similarity between Atlantic heat transport and the Agulhas Leakage suggests that it is the source of the surface heat transport anomalies. The freshwater budget in the North Atlantic is dominated by a decrease in freshwater flux. The increasing salinity during the slowdown supports modeling studies that show that heat, not freshwater, drives trends in the overturning circulation in a warming climate.

The response of high-impact blocking weather systems to climate change (Kennedy et al. 2016)

Abstract: Midlatitude weather and climate are dominated by the jet streams and associated eastward moving storm systems. Occasionally, however, these are blocked by persistent anticyclonic regimes known as blocking. Climate models generally predict a small decline in blocking frequency under anthropogenic climate change. However, confidence in these predictions is undermined by, among other things, a lack of understanding of the physical mechanisms underlying the change. Here we analyze blocking (mostly in the Euro-Atlantic sector) in a set of sensitivity experiments to determine the effect of different parts of the surface global warming pattern. We also analyze projected changes in the impacts of blocking such as temperature extremes. The results show that enhanced warming both in the tropics and over the Arctic act to strengthen the projected decline in blocking. The tropical changes are more important for the uncertainty in projected blocking changes, though the Arctic also affects the temperature anomalies during blocking.

The anomalous change in the QBO in 2015-16 (Newman et al. 2016)

Abstract: The quasi-biennial oscillation (QBO) is a tropical lower stratospheric, downward propagating zonal wind variation, with an average period of ~28 months. The QBO has been constantly documented since 1953. Here we describe the evolution of the QBO during the Northern Hemisphere winter of 2015-16 using radiosonde observations and meteorological reanalyses. Normally, the QBO would show a steady downward propagation of the westerly phase. In 2015-16, there was an anomalous upward displacement of this westerly phase from ~30 hPa to 15 hPa. These westerlies impinge on, or “cut-off” the normal downward propagation of the easterly phase. In addition, easterly winds develop at 40 hPa. Comparisons to tropical wind statistics for the 1953-present record demonstrate that this 2015-16 QBO disruption is unprecedented.

Other papers

Impact of observed North Atlantic multidecadal variations to European summer climate: a linear baroclinic response to surface heating (Ghosh et al. 2016)

Gridded, monthly rainfall and temperature climatology for El Niño Southern Oscillation impacts in the United States (Dourte et al. 2016)

Southern European rainfall reshapes the early-summer circumglobal teleconnection after the late 1970s (Lin et al. 2016)

Moisture and heat budgets of the south American monsoon system: climatological aspects (Garcia et al. 2016)

The Relative Influence of ENSO and SAM on Antarctic Peninsula Climate (Clem et al. 2016)

Sinuosity of mid-latitude atmospheric flow in a warming world (Cattiaux et al. 2016)

ENSO response to high-latitude volcanic eruptions in the Northern Hemisphere: The role of the initial conditions (Pausata et al. 2016)

Remote influence of Interdecadal Pacific Oscillation on the South Atlantic Meridional Overturning Circulation variability (Lopez et al. 2016)

Robust response of the Amundsen Sea Low to stratospheric ozone depletion (England et al. 2016)

The response of winter Pacific North American pattern to strong volcanic eruptions (Liu et al. 2016)

Atlantic Multidecadal Variability in a model with an improved North Atlantic Current (Drews & Greatbatch, 2016)

Sub-decadal North Atlantic Oscillation variability in observations and the Kiel Climate Model (Reintges, Latif & Park, 2016)

Is there a robust effect of anthropogenic aerosols on the Southern Annular Mode? (Steptoe et al. 2016)

Climate Signals in the Mid- to High-Latitude North Atlantic from Altimeter Observations (Li et al. 2016)

Intensification and poleward shift of subtropical western boundary currents in a warming climate (Yang et al. 2016)

Inter-basin effects of the Indian Ocean on Pacific decadal climate change (Mochizuki et al. 2016)

The influence of boreal spring Arctic Oscillation on the subsequent winter ENSO in CMIP5 models (Chen et al. 2016)

Relationship between North American winter temperature and large-scale atmospheric circulation anomalies and its decadal variation (Yu et al. 2016)

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New research – carbon cycle (August 9, 2016)

Posted by Ari Jokimäki on August 9, 2016

Some of the latest papers on carbon cycle are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Sources of uncertainty in future projections of the carbon cycle (Hewitt et al. 2016)

Abstract: The inclusion of carbon cycle processes within CMIP5 Earth System Models provides the opportunity to explore the relative importance of differences in scenario and climate model representation to future land and ocean carbon fluxes. A two-way ANOVA approach was used to quantify the variability owing to differences between scenarios and between climate models at different lead times.

For global ocean carbon fluxes, the variance attributed to differences between Representative Concentration Pathway scenarios exceeds the variance attributed to differences between climate models by around 2025, completely dominating by 2100. This contrasts with global land carbon fluxes, where the variance attributed to differences between climate models continues to dominate beyond 2100. This suggests that modelled processes that determine ocean fluxes are currently better constrained than those of land fluxes, thus we can be more confident in linking different future socio-economic pathways to consequences of ocean carbon uptake than for land carbon uptake. The contribution of internal variance is negligible for ocean fluxes and small for land fluxes, indicating that there is little dependence on the initial conditions.

The apparent agreement in atmosphere-ocean carbon fluxes, globally, masks strong climate model differences at a regional level. The North Atlantic and Southern Ocean are key regions, where differences in modelled processes represent an important source of variability in projected regional fluxes.

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands (Jones et al. 2016)

Abstract: Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (100 years) in two Interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the pre-thaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post-thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its pre-thaw C stocks; the amount of time needed for them to regain their pre-thaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover pre-thaw C stocks, whereas younger peatlands will exceed pre-thaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands.

Ectomycorrhizal fungi slow soil carbon cycling (Averill & Hawkes, 2016)

Abstract: Respiration of soil organic carbon is one of the largest fluxes of CO2 on earth. Understanding the processes that regulate soil respiration is critical for predicting future climate. Recent work has suggested that soil carbon respiration may be reduced by competition for nitrogen between symbiotic ectomycorrhizal fungi that associate with plant roots and free-living microbial decomposers, which is consistent with increased soil carbon storage in ectomycorrhizal ecosystems globally. However, experimental tests of the mycorrhizal competition hypothesis are lacking. Here we show that ectomycorrhizal roots and hyphae decrease soil carbon respiration rates by up to 67% under field conditions in two separate field exclusion experiments, and this likely occurs via competition for soil nitrogen, an effect larger than 2 °C soil warming. These findings support mycorrhizal competition for nitrogen as an independent driver of soil carbon balance and demonstrate the need to understand microbial community interactions to predict ecosystem feedbacks to global climate.

Brazil’s Amazonian forest carbon: the key to Southern Amazonia’s significance for global climate (Fearnside, 2016)

Abstract: Southern Amazonia is the first region of Brazil’s Amazon area to be exposed to intensive conversion to agriculture and ranching. This conversion emits greenhouse gases from the carbon stock in the biomass and soils of the previous vegetation. Quantifying these carbon stocks is the first step in quantifying the impact on global warming from this conversion. This review is limited to information on Brazilian Amazonia’s carbon stocks. It indicates large amounts of carbon at risk of emission in both biomass and soils, as well as considerable uncertainty in estimates. Reducing uncertainty is a priority for research but the existence of uncertainty must not be used as an excuse for delaying measures to contain deforestation. The magnitude of carbon stocks is proportional to greenhouse gas emissions per hectare of deforestation and consequently to impact on global climate.

Long-term drainage reduces CO2 uptake and increases CO2 emission on a Siberian floodplain due to shifts in vegetation community and soil thermal characteristics (Kwon et al. 2016)

Abstract: With increasing air temperatures and changing precipitation patterns forecast for the Arctic over the coming decades, the thawing of ice-rich permafrost is expected to increasingly alter hydrological conditions by creating mosaics of wetter and drier areas. The objective of this study is to investigate how 10 years of lowered water table depths of wet floodplain ecosystems would affect CO2 fluxes measured using a closed chamber system, focusing on the role of long-term changes in soil thermal characteristics and vegetation community structure. Drainage diminishes the heat capacity and thermal conductivity of organic soil, leading to warmer soil temperatures in shallow layers during the daytime and colder soil temperatures in deeper layers, resulting in a reduction in thaw depths. These soil temperature changes can intensify growing-season heterotrophic respiration by up to 95 %. With decreased autotrophic respiration due to reduced gross primary production under these dry conditions, the differences in ecosystem respiration rates in the present study were 25 %. We also found that a decade-long drainage installation significantly increased shrub abundance, while decreasing Eriophorum angustifolium abundance resulted in Carex sp. dominance. These two changes had opposing influences on gross primary production during the growing season: while the increased abundance of shrubs slightly increased gross primary production, the replacement of E. angustifolium by Carex sp. significantly decreased it. With the effects of ecosystem respiration and gross primary production combined, net CO2 uptake rates varied between the two years, which can be attributed to Carex-dominated plots’ sensitivity to climate. However, underlying processes showed consistent patterns: 10 years of drainage increased soil temperatures in shallow layers and replaced E. angustifolium by Carex sp., which increased CO2 emission and reduced CO2 uptake rates. During the non-growing season, drainage resulted in 4 times more CO2 emissions, with high sporadic fluxes; these fluxes were induced by soil temperatures, E. angustifolium abundance, and air pressure.

Other papers

Quantifying Peat Carbon Accumulation in Alaska Using a Process-Based Biogeochemistry Model (Wang et al. 2016)

Patterns of carbon processing at the seafloor: the role of faunal and microbial communities in moderating carbon flows (Woulds et al. 2016)

Informing climate models with rapid chamber measurements of forest carbon uptake (Metcalfe et al. 2016)

Direct and indirect effects of climatic variations on the interannual variability in net ecosystem exchange across terrestrial ecosystems (Shao et al. 2016)

Decadal and long-term boreal soil carbon and nitrogen sequestration rates across a variety of ecosystems (Manies et al. 2016)

Hotspots of gross emissions from the land use sector: patterns, uncertainties, and leading emission sources for the period 2000–2005 in the tropics (Roman-Cuesta et al. 2016)

Large net CO2 loss from a grass-dominated tropical savanna in south-central Brazil in response to seasonal and interannual drought (De Arruda et al. 2016)

How much CO2 is taken up by the European terrestrial biosphere? (Reuter et al. 2016)

Coastal-ocean uptake of anthropogenic carbon (Bourgeois et al. 2016)

Drivers of atmospheric methane uptake by montane forest soils in the southern Peruvian Andes (Jones et al. 2016)

Persistent high temperature and low precipitation reduce peat carbon accumulation (Delarue, 2016)

Methane oxidation in contrasting soil types: responses to experimental warming with implication for landscape-integrated CH4 budget (D’Imperio et al. 2016)

Seeing the forest not for the carbon: why concentrating on land-use-induced carbon stock changes of soils in Brazil can be climate-unfriendly (Boy et al. 2016)

Stability of grassland soil C and N pools despite 25 years of an extreme climatic and disturbance regime (Wilcox et al. 2016)

Regional carbon fluxes from land use and land cover change in Asia, 1980–2009 (Calle et al. 2016)

Carbon cycle responses of semi-arid ecosystems to positive asymmetry in rainfall (Haverd et al. 2016)

Impact of increasing inflow of warm Atlantic water on the sea-air exchange of carbon dioxide and methane in the Laptev Sea (Wåhlström et al. 2016)

Air-sea exchange of carbon dioxide in the Southern Ocean and Antarctic marginal ice zone (Butterworth & Miller, 2016)

Earlier snowmelt reduces atmospheric carbon uptake in mid-latitude subalpine forests (Winchell et al. 2016)

Four decades of modeling methane cycling in terrestrial ecosystems (Xu et al. 2016)

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New research – hydrosphere (August 3, 2016)

Posted by Ari Jokimäki on August 3, 2016

Some of the latest papers on hydrosphere (oceans, lakes, ponds, rivers, streams, etc.) are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Comparison of Global Precipitation Estimates across a Range of Temporal and Spatial Scales (Gehne et al. 2016)

Abstract: Characteristics of precipitation estimates for rate and amount from three global High-resolution precipitation products (HRPPs), four global Climate Data Records (CDRs), and four reanalyses are compared. All data sets considered have at least daily temporal resolution. Estimates of global precipitation differ widely from one product to the next, with some differences likely due to differing goals in producing the estimates. HRPPs are intended to produce the best snapshot of the precipitation estimate locally. CDRs of precipitation emphasize homogeneity over instantaneous accuracy. Precipitation estimates from global reanalyses are dynamically consistent with the large scale circulation but tend to compare poorly to rain gauge estimates since they are forecast by the reanalysis system and precipitation is not assimilated. Regional differences among the estimates in the means and variances are as large as the means and variances, respectively. Even with similar monthly totals, precipitation rates vary significantly among the estimates. Temporal correlations among data sets are large at annual and daily time scales, suggesting that compensating bias errors at annual and random errors at daily time scales dominate the differences. However, the signal to noise ratio at intermediate (monthly) time scales can be large enough to result in high correlations overall. It is shown that differences on annual time scales and continental regions are around 0.8mm/d, which corresponds to 23W m−2. These wide variations in the estimates, even for global averages, highlight the need for better constrained precipitation products in the future.

Stable reconstruction of Arctic sea level for the 1950–2010 period (Svendsen et al. 2016)

Abstract: Reconstruction of historical Arctic sea level is generally difficult due to the limited coverage and quality of both tide gauge and altimetry data in the area. Here a strategy to achieve a stable and plausible reconstruction of Arctic sea level from 1950 to today is presented. This work is based on the combination of tide gauge records and a new 20-year reprocessed satellite altimetry derived sea level pattern. Hence the study is limited to the area covered by satellite altimetry (68ºN and 82ºN). It is found that timestep cumulative reconstruction as suggested by Church and White (2000) may yield widely variable results and is difficult to stabilize due to the many gaps in both tide gauge and satellite data. A more robust sea level reconstruction approach is to use datum adjustment of the tide gauges in combination with satellite altimetry, as described by (Ray and Douglas, 2011). In this approach, a datum-fit of each tide gauges is used and the method takes into account the entirety of each tide gauge record. This makes the Arctic sea level reconstruction much less prone to drifting.

From our reconstruction, we found that the Arctic mean sea level trend is around 1.5 mm +/- 0.3 mm/y for the period 1950 to 2010, between 68ºN and 82ºN. This value is in good agreement with the global mean trend of 1.8 +/- 0.3 mm/y over the same period as found by Church and White (2004).

Lake Vanda: A sentinel for climate change in the McMurdo Sound Region of Antarctica (Castendyk et al. 2016)

Abstract: Lake Vanda is a perennially ice-covered, meromictic, endorheic lake located in the McMurdo Dry Valleys of Antarctica, and an exceptional sentinel of climate change within the region. Lake levels rose 15 m over the past 68 years in response to climate-driven variability in ice-cover sublimation, meltwater production, and annual discharge of the Onyx River, the main source of water to the lake. Evidence from a new bathymetric map and water balance model combined with annual growth laminations in benthic mats suggest that the most recent filling trend began abruptly 80 years ago, in the early 1930s. This change increased lake volume by > 50%, triggered the formation of a new, upper, thermohaline convection cell, and cooled the lower convection cell cooled by at least 2 °C and the bottom-most waters by at > 4 °C. Additionally, the depth of the deep chlorophyll a maximum rose by > 2 m, and deep-growing benthic algal mats declined while shallow benthic mats colonized freshly inundated areas. We attribute changes in hydrology to regional variations in air flow related to the strength and position of the Amundsen Sea Low (ASL) pressure system which have increased the frequency of down-valley, föhn winds associated with surface air temperature warming in the McMurdo Dry Valleys. The ASL has also been implicated in the recent warming of the Antarctic Peninsula, and provides a common link for climate-related change on opposite sides of the continent. If this trend persists, Lake Vanda should continue to rise and cool over the next 200 years until a new equilibrium lake level is achieved. Most likely, future lake rise will lead to isothermal conditions not conducive to thermohaline convection, resulting in a drastically different physical, biogeochemical, and biological structure than observed today.

Ocean acidification in the subpolar North Atlantic: rates and mechanisms controlling pH changes (García-Ibáñez et al. 2016)

Abstract: Repeated hydrographic sections provide critically needed data on and understanding of changes in basin-wide ocean CO2 chemistry over multi-decadal timescales. Here, high-quality measurements collected at twelve cruises carried out along the same track between 1991 and 2015 have been used to determine long-term changes in ocean CO2 chemistry and ocean acidification in the Irminger and Iceland basins of the North Atlantic Ocean. Trends were determined for each of the main water masses present and are discussed in the context of the basin-wide circulation. The pH has decreased in all water masses of the Irminger and Iceland basins over the past 25 years with the greatest changes in surface and intermediate waters (between −0.0010 ± 0.0001 and −0.0018 ± 0.0001 pH units yr-1). In order to disentangle the drivers of the pH changes, we decomposed the trends into their principal drivers: changes in temperature, salinity, total alkalinity (AT) and total dissolved inorganic carbon (both its natural and anthropogenic components). The increase in anthropogenic CO2 (Cant) was identified as the main agent of the pH decline, partially offset by AT increases. The acidification of intermediate waters caused by Cant uptake has been reinforced by the aging of the water masses over the period of our analysis. The pH decrease of the deep overflow waters in the Irminger basin was similar to that observed in the upper ocean and was mainly linked to the Cant increase, thus reflecting the recent contact of these deep waters with the atmosphere.

Uncertainty in the Himalayan energy–water nexus: estimating regional exposure to glacial lake outburst floods (Schwanghart et al. 2016)

Abstract: Himalayan water resources attract a rapidly growing number of hydroelectric power projects (HPP) to satisfy Asia’s soaring energy demands. Yet HPP operating or planned in steep, glacier-fed mountain rivers face hazards of glacial lake outburst floods (GLOFs) that can damage hydropower infrastructure, alter water and sediment yields, and compromise livelihoods downstream. Detailed appraisals of such GLOF hazards are limited to case studies, however, and a more comprehensive, systematic analysis remains elusive. To this end we estimate the regional exposure of 257 Himalayan HPP to GLOFs, using a flood-wave propagation model fed by Monte Carlo-derived outburst volumes of >2300 glacial lakes. We interpret the spread of thus modeled peak discharges as a predictive uncertainty that arises mainly from outburst volumes and dam-breach rates that are difficult to assess before dams fail. With 66% of sampled HPP are on potential GLOF tracks, up to one third of these HPP could experience GLOF discharges well above local design floods, as hydropower development continues to seek higher sites closer to glacial lakes. We compute that this systematic push of HPP into headwaters effectively doubles the uncertainty about GLOF peak discharge in these locations. Peak discharges farther downstream, in contrast, are easier to predict because GLOF waves attenuate rapidly. Considering this systematic pattern of regional GLOF exposure might aid the site selection of future Himalayan HPP. Our method can augment, and help to regularly update, current hazard assessments, given that global warming is likely changing the number and size of Himalayan meltwater lakes.

Other papers

Temporal and spatial variability of rainfall over Greece (Markonis et al. 2016)

The marine hydrological cycle: the Ocean’s floods and droughts (Gordon, 2016)

The Contribution of Glacial Isostatic Adjustment to Projections of Sea Level Change Along the Atlantic and Gulf Coasts of North America (Love et al. 2016)

Modeled ecohydrological responses to climate change at seven small watersheds in the northeastern U.S (Pourmokhtarian et al. 2016)

Data-model comparison of temporal variability in long-term time series of large-scale soil moisture (Verrot & Destouni, 2016)

February drying in southeast Brazil and the Australian monsoon: Global mechanism for a regional rainfall feature (Kelly & Mapes, 2016)

Monotonic trends in spatio-temporal distribution and concentration of monsoon precipitation (1901–2002), West Bengal, India (Chatterjee et al. 2016)

The Curious Nature of the Hemispheric Symmetry of the Earth’s Water and Energy Balances (Stephens et al. 2016)

Aragonite saturation states and pH in western Norwegian fjords: seasonal cycles and controlling factors, 2005–2009 (Omar et al. 2016)

Elevation change and the vulnerability of Rhode Island (USA) salt marshes to sea-level rise (Raposa et al. 2016)

Precipitation sensitivity to warming estimated from long island records (Polson et al. 2016)

Stomatal response to humidity and CO2 implicated in recent decline in U.S. evaporation (Rigden & Salvucci, 2016)

International energy trade impacts on water resource crises: an embodied water flows perspective (Zhang et al. 2016)

Statistical analyses of potential evapotranspiration changes over the period 1930–2012 in the Nile River riparian countries (Onyutha, 2016)

The influence from the shrinking cryosphere and strengthening evopotranspiration on hydrologic process in a cold basin, Qilian Mountains (Zongxing et al. 2016)

Enhanced summer convective rainfall at Alpine high elevations in response to climate warming (Giorgi et al. 2016)

Assessing the impact of vertical land motion on 20th century global mean sea level estimates (Hamlington et al. 2016)

No observed effect of ocean acidification on nitrogen biogeochemistry in a summer Baltic Sea plankton community (Paul et al. 2016)

Snowmelt Rate Dictates Streamflow (Barnhart et al. 2016)

Impacts of open-ocean deep convection in the Weddell Sea on coastal and bottom water temperature (Wang et al. 2016)

Intensification of upwelling along Oman coast in a Warming Scenario (Praveen et al. 2016)

Ocean acidification affects marine chemical communication by changing structure and function of peptide signalling molecules (Roggatz et al. 2016)

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New research – extreme weather (July 31, 2016)

Posted by Ari Jokimäki on July 31, 2016

Some of the latest papers on extreme weather are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Drivers of exceptionally cold North Atlantic Ocean temperatures and their link to the 2015 European heat wave (Duchez et al. 2016)

Abstract: The North Atlantic and Europe experienced two extreme climate events in 2015: exceptionally cold ocean surface temperatures and a summer heat wave ranked in the top ten over the past 65 years. Here, we show that the cold ocean temperatures were the most extreme in the modern record over much of the mid-high latitude North-East Atlantic. Further, by considering surface heat loss, ocean heat content and wind driven upwelling we explain for the first time the genesis of this cold ocean anomaly. We find that it is primarily due to extreme ocean heat loss driven by atmospheric circulation changes in the preceding two winters combined with the re-emergence of cold ocean water masses. Furthermore, we reveal that a similar cold Atlantic anomaly was also present prior to the most extreme European heat waves since the 1980s indicating that it is a common factor in the development of these events. For the specific case of 2015, we show that the ocean anomaly is linked to a stationary position of the Jet Stream that favours the development of high surface temperatures over Central Europe during the heat wave. Our study calls for an urgent assessment of the impact of ocean drivers on major European summer temperature extremes in order to provide better advance warning measures of these high societal impact events.

Predicting Atlantic seasonal hurricane activity using outgoing longwave radiation over Africa (Karnauskas & Li, 2016)

Abstract: Seasonal hurricane activity is a function of the amount of initial disturbances (e.g., easterly waves) and the background environment in which they develop into tropical storms (i.e., the main development region). Focusing on the former, a set of indices based solely upon the meridional structure of satellite-derived outgoing longwave radiation (OLR) over the African continent are shown to be capable of predicting Atlantic seasonal hurricane activity with very high rates of success. Predictions of named storms based on the July OLR field and trained only on the time period prior to the year being predicted yield a success rate of 87%, compared to the success rate of NOAA’s August outlooks of 53% over the same period and with the same average uncertainty range (±2). The resulting OLR indices are statistically robust, highly detectable, physically linked to the predictand, and may account for longer-term observed trends.

Seasonal mean temperature changes control future heat waves (Argüeso et al. 2016)

Abstract: Increased temperature will result in longer, more frequent, and more intense heat waves. Changes in temperature variability have been deemed necessary to account for future heat wave characteristics. However, this has been quantified only in Europe and North America, while the rest of the globe remains unexplored. Using late century global climate projections, we show that annual mean temperature increases is the key factor defining heat wave changes in most regions. We find that commonly studied areas are an exception rather than the standard and the mean climate change signal generally outweighs any influence from variability changes. More importantly, differences in warming across seasons are responsible for most of the heat wave changes and their consideration relegates the contribution of variability to a marginal role. This reveals that accurately capturing mean seasonal changes is crucial to estimate future heat waves and reframes our interpretation of future temperature extremes.

A Review of Drought in the Middle East and Southwest Asia (Barlow et al. 2016)

Abstract: The Middle East and Southwest Asia comprise a region that is water-stressed, societally vulnerable, and prone to severe droughts. Large-scale climate variability, particularly La Niña, appears to play an important role in region-wide drought, including the two most severe of the last fifty years—1999-2001 and 2007-2008—with implications for drought forecasting. Important dynamical factors include orography, thermodynamic influence on vertical motion, storm track changes, and moisture transport. Vegetation in the region is strongly impacted by drought and may provide an important feedback mechanism. In future projections, drying of the eastern Mediterranean is a robust feature, as are temperature increases throughout the region, which will affect evaporation and the timing and intensity of snowmelt. Vegetation feedbacks may become more important in a warming climate.

There are a wide range of outstanding issues for understanding, monitoring, and predicting drought in the region, including: dynamics of the regional storm track, the relative importance of the range of dynamical mechanisms related to drought, regional coherence of drought, the relationship between synoptic-scale mechanisms and drought, predictability of vegetation and crop yields, stability of remote influences, data uncertainty, and the role of temperature. Development of a regional framework for cooperative work and dissemination of information and existing forecasts would speed understanding and make better use of available information.

Should flood regimes change in a warming climate? The role of antecedent moisture conditions (Woldemeskel & Sharma, 2016)

Abstract: Assessing changes to flooding is important for designing new and redesigning existing infrastructure to withstand future climates. While there is speculation that floods are likely to intensify in the future, this question is often difficult to assess due to inadequate records on streamflow extremes. An alternate way of determining possible extreme flooding is through assessment of the two key factors that lead to the intensification of floods: the intensification of causative rainfall and changes in the wetness conditions prior to rainfall. This study assesses global changes in the antecedent wetness prior to extreme rainfall. Our results indicate a significant increase in the antecedent moisture in Australia and Africa over the last century; however, there was also a decrease in Eurasia and insignificant change in North America. Given the nature of changes found in this study, any future flood assessment for global warming conditions should take into account antecedent moisture conditions.

Other papers

The evolution of temperature extremes in the Gaspé Peninsula, Quebec, Canada (1974–2013) (Fortin et al. 2016)

On the emergence of rainfall extremes from ordinary events (Zorzetto et al. 2016)

Changes of extreme drought and flood events in Iran (Modarres, Sarhadi & Burn, 2016)

An integrated analysis of the March 2015 Atacama floods (Wilcox et al. 2016)

Tropical cyclones in the GISS ModelE2 (Camargo et al. 2016)

Trends and variability in extremes of precipitation in Curitiba – Southern Brazil (Pedron et al. 2016)

North Atlantic Storm Track Sensitivity to Projected Sea Surface Temperature: Local versus Remote Influences (Ciasto et al. 2016)

Observed changes in extreme temperature and precipitation over Indonesia (Supari et al. 2016)

A Modeling Study of the Causes and Predictability of the Spring 2011 Extreme US Weather Activity (Schubert et al. 2016)

A Situation-based Analysis of Flash Flood Fatalities in the United States (Terti et al. 2016)

Climatology and trend analysis of extreme precipitation in subregions of Northeast Brazil (Oliveira et al. 2016)

Can we predict seasonal changes in high impact weather in the United States? (Jung & Kirtman, 2016)

Does population affect the location of flash flood reports? (Marjerison et al. 2016)

The Physics of Drought in the U.S. Central Great Plains (Livneh & Hoerling, 2016)

Heat wave over India during summer 2015: an assessment of real time extended range forecast (Pattanaik et al. 2016)

Investigation of the 2013 Alberta flood from weather and climate perspectives (Teufel et al. 2016)

Posted in Climate science, Global warming effects | Leave a Comment »

New research – climate change impacts on mankind (July 28, 2016)

Posted by Ari Jokimäki on July 28, 2016

Some of the latest papers on climate change impacts on mankind are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Attributing human mortality during extreme heat waves to anthropogenic climate change (Mitchell et al. 2016)

Abstract: It has been argued that climate change is the biggest global health threat of the 21st century. The extreme high temperatures of the summer of 2003 were associated with up to seventy thousand excess deaths across Europe. Previous studies have attributed the meteorological event to the human influence on climate, or examined the role of heat waves on human health. Here, for the first time, we explicitly quantify the role of human activity on climate and heat-related mortality in an event attribution framework, analysing both the Europe-wide temperature response in 2003, and localised responses over London and Paris. Using publicly-donated computing, we perform many thousands of climate simulations of a high-resolution regional climate model. This allows generation of a comprehensive statistical description of the 2003 event and the role of human influence within it, using the results as input to a health impact assessment model of human mortality. We find large-scale dynamical modes of atmospheric variability remain largely unchanged under anthropogenic climate change, and hence the direct thermodynamical response is mainly responsible for the increased mortality. In summer 2003, anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ~70% and by ~20% in London, which experienced lower extreme heat. Out of the estimated ~315 and ~735 summer deaths attributed to the heatwave event in Greater London and Central Paris, respectively, 64 (±3) deaths were attributable to anthropogenic climate change in London, and 506 (±51) in Paris. Such an ability to robustly attribute specific damages to anthropogenic drivers of increased extreme heat can inform societal responses to, and responsibilities for, climate change.

Climate change and migration in the Pacific: options for Tuvalu and the Marshall Islands (Constable, 2016)

Abstract: As climate change impacts, particularly rising sea levels, manifest there is a high probability that some island populations will be faced with the need to relocate. This article discusses several discourses around migration options for people affected by climate change impacts in small island developing states. Options currently available to citizens of the Pacific nations of Tuvalu and the Marshall Islands are explored, including the perspective that high levels of customary land tenure in the Pacific are a barrier to permanent movement to other Pacific countries. Migration to Pacific Rim countries such as Australia, New Zealand and the USA is complicated by strict migration eligibility criteria, which often require proof of language abilities and income, and may restrict the number of accompanying dependants. The Compact of Free Association provides visa-free entry to the USA for citizens of the Marshall Islands, but the lack of financial assistance restricts eligibility to those with existing financial resources or family networks that can provide access to capital. The difficulty of directly attributing single weather/climate events to climate change hinders the formulation of a definition of climate change-related migration. This obstacle in turn hinders the establishment of effective visa categories and migration routes for what is likely to become a growing number of people in coming decades.

Rural drinking water issues in India’s drought-prone area: a case of Maharashtra state (Udmale et al. 2016)

Abstract: Obtaining sufficient drinking water with acceptable quality under circumstances of lack, such as droughts, is a challenge in drought-prone areas of India. This study examined rural drinking water availability issues during a recent drought (2012) through 22 focus group discussions (FGDs) in a drought-prone catchment of India. Also, a small chemical water quality study was undertaken to evaluate the suitability of water for drinking purpose based on Bureau of Indian Standards (BIS). The drought that began in 2011 and further deteriorated water supplies in 2012 caused a rapid decline in reservoir storages and groundwater levels that led, in turn, to the failure of the public water supply systems in the Upper Bhima Catchment. Dried up and low-yield dug wells and borewells, tanker water deliveries from remote sources, untimely water deliveries, and degraded water quality were the major problems identified in the FGDs. In addition to severe drinking water scarcity during drought, the quality of the drinking water was found to be a major problem, and it apparently was neglected by local governments and users. Severe contamination of the drinking water with nitrate-nitrogen, ammonium-nitrogen, and chlorides was found in the analyzed drinking water samples. Hence, in addition to the water scarcity, the results of this study point to an immediate need to investigate the problem of contaminated drinking water sources while designing relief measures for drought-prone areas of India.

Climate change impacts on European agriculture revisited: adding the economic dimension of grasslands (Aghajanzadeh-Darzi et al. 2016)

Abstract: Forage and more widely grassland systems are difficult to analyze in economic terms because a large proportion of what is produced is not marketed. Economic misestimation of these farm products may dramatically alter projected climate change impacts. This study estimates the economic value of grass and assesses the impact of climatic variations on grassland–livestock systems by taking various environmental and climatic factors into account. Accordingly, grass yield responses to nitrogen inputs (N-yield functions) have been simulated using the grassland biogeochemical PaSim model and then fed into the economic farm-type supply AROPAj model. We developed a computational method to estimate shadow prices of grass production, allowing us to better estimate the effects of climatic variability on grassland and crop systems. This approach has been used on a European scale under two Intergovernmental Panel on Climate Change climate scenarios (AR4 A2 and B1). Results show a significant change in land use over time. Accordingly, due to decreases in feed expenses, farmers may increase livestock, thereby increasing overall greenhouse gas emissions for all scenarios considered. As part of autonomous adaptation by farming systems, N-yield functions extending to pastures and fodders allow us to improve the model and to refine results when marketed and non-marketed crops are considered in a balanced way.

Impacts of Climate Change on the Collapse of Lowland Maya Civilization (Douglas et al. 2016)

Abstract: Paleoclimatologists have discovered abundant evidence that droughts coincided with collapse of the Lowland Classic Maya civilization, and some argue that climate change contributed to societal disintegration. Many archaeologists, however, maintain that drought cannot explain the timing or complex nature of societal changes at the end of the Classic Period, between the eighth and eleventh centuries ce. This review presents a compilation of climate proxy data indicating that droughts in the ninth to eleventh century were the most severe and frequent in Maya prehistory. Comparison with recent archaeological evidence, however, indicates an earlier beginning for complex economic and political processes that led to the disintegration of states in the southern region of the Maya lowlands that precedes major droughts. Nonetheless, drought clearly contributed to the unusual severity of the Classic Maya collapse, and helped to inhibit the type of recovery seen in earlier periods of Maya prehistory. In the drier northern Maya Lowlands, a later political collapse at ca. 1000 ce appears to be related to ongoing extreme drought. Future interdisciplinary research should use more refined climatological and archaeological data to examine the relationship between climate and social processes throughout the entirety of Maya prehistory.

Other papers

Death from respiratory diseases and temperature in Shiraz, Iran (2006–2011) (Dadbakhsh et al. 2016)

Food security in the face of climate change: Adaptive capacity of small-scale social-ecological systems to environmental variability (Pérez et al. 2016)

Precipitation Effects on Motor Vehicle Crashes Vary by Space, Time and Environmental Conditions (Tamerius et al. 2016)

The potential for adoption of climate smart agricultural practices in Sub-Saharan livestock systems (de Jalón et al. 2016)

Can Gridded Precipitation Data and Phenological Observations Reduce Basis Risk of Weather Index-based Insurance? (Dalhaus et al. 2016)

Sea surface temperature impacts on winter cropping systems in the Iberian Peninsula (Capa-Morocho et al. 2016)

Separating the effects of phenology and diffuse radiation on gross primary productivity in winter wheat (Williams et al. 2016)

Risk matrix approach useful in adapting agriculture to climate change (Cobon et al. 2016)

Heat-related mortality: Effect modification and adaptation in Japan from 1972 to 2010 (Ng et al. 2016)

The effect of extreme cold temperatures on the risk of death in the two major Portuguese cities (Antunes et al. 2016)

Social and cultural issues raised by climate change in Pacific Island countries: an overview (Weir et al. 2016)

Protein futures for Western Europe: potential land use and climate impacts in 2050 (Röös et al. 2016)

“Climate change damages”, conceptualization of a legal notion with regard to reparation under international law (Kugler & Sariego, 2016)

Temperature deviation index and elderly mortality in Japan (Lim et al. 2016)

Climatic influence on corn sowing date in the Midwestern United States (Choi et al. 2016)

New Zealand kiwifruit growers’ vulnerability to climate and other stressors (Cradock-Henry, 2016)

Climate change impacts and adaptive strategies: lessons from the grapevine (Mosedale et al. 2016)

Posted in Adaptation & Mitigation, Global warming effects | Leave a Comment »

New research – climate change impacts on cryosphere (July 23, 2016)

Posted by Ari Jokimäki on July 23, 2016

Some of the latest papers on climate change impacts on cryosphere are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Antarctic sea-ice expansion between 2000 and 2014 driven by tropical Pacific decadal climate variability

Abstract: Antarctic sea-ice extent has been slowly increasing in the satellite record that began in 1979. Since the late 1990s, the increase has accelerated, but the average of all climate models shows a decline. Meanwhile, the Interdecadal Pacific Oscillation, an internally generated mode of climate variability, transitioned from positive to negative, with an average cooling of tropical Pacific sea surface temperatures, a slowdown of the global warming trend and a deepening of the Amundsen Sea Low near Antarctica that has contributed to regional circulation changes in the Ross Sea region and expansion of sea ice. Here we show that the negative phase of the Interdecadal Pacific Oscillation in global coupled climate models is characterized by anomalies similar to the observed sea-level pressure and near-surface 850 hPa wind changes near Antarctica since 2000 that are conducive to expanding Antarctic sea-ice extent, particularly in the Ross Sea region in all seasons, involving a deepening of the Amundsen Sea Low. These atmospheric circulation changes are shown to be mainly driven by precipitation and convective heating anomalies related to the Interdecadal Pacific Oscillation in the equatorial eastern Pacific, with additional contributions from convective heating anomalies in the South Pacific convergence zone and tropical Atlantic regions.

Million year old ice found under meter thick debris layer in Antarctica

Abstract: Cosmogenic nuclide measurements associated with buried glacier ice in Ong Valley, in the Transantarctic Mountains, suggest the preservation of ancient ice. There are three glacial tills on the valley floor which have formed from the concentration of regolith contained within sublimating glacier ice. Two tills are less than 1 m thick and underlain by ice. Measurements of cosmogenic 10Be, 26Al, and 21Ne show that (i) the youngest buried ice unit and corresponding till are at least 11–13 ka, (ii) another ice unit and corresponding intermediate-age till are at least 1.1 Ma old under any circumstances and most likely older than 1.78 Ma, and (iii) the oldest till is at least 1.57 Ma and most likely greater than 2.63 Ma. These observations highlight the longevity of ice under thin debris layers and the potential to sample ancient ice for paleoclimate/paleoatmosphere information close to the present land surface.

Accelerating retreat and high-elevation thinning of glaciers in central Spitsbergen

Abstract: Svalbard is a heavily glacier-covered archipelago in the Arctic. Dickson Land (DL), in the central part of the largest island, Spitsbergen, is relatively arid and, as a result, glaciers there are relatively small and restricted mostly to valleys and cirques. This study presents a comprehensive analysis of glacier changes in DL based on inventories compiled from topographic maps and digital elevation models for the Little Ice Age (LIA) maximum, the 1960s, 1990, and 2009/2011. Total glacier area has decreased by  ∼ 38 % since the LIA maximum, and front retreat increased over the study period. Recently, most of the local glaciers have been consistently thinning in all elevation bands, in contrast to larger Svalbard ice masses which remain closer to balance. The mean 1990–2009/2011 geodetic mass balance of glaciers in DL is among the most negative from the Svalbard regional means known from the literature.

The Andes Cordillera. Part I: snow distribution, properties, and trends (1979–2014)

Abstract: Snow cover presence, duration, properties, and water amount play a major role in Earth’s climate system through its impact on the surface energy budget. Snow cover conditions and trends (1979–2014) were simulated for South America – for the entire Andes Cordillera. Recent data sets and SnowModel developments allow relatively high-resolutions of 3-h time step and 4-km horizontal grid increment for this domain. US Geological Survey’s Global Multi-resolution Terrain Elevation Data 2010 topography, Global Land Cover (GlobCover), Randolph Glacier Inventory (v. 4.0) glacier, and NASA modern-era retrospective analysis for research and applications data sets were used to simulate first-order atmospheric forcing (e.g. near-surface air temperature and precipitation, including the fraction of precipitation falling as snow) and terrestrial snow characteristics (e.g. snow cover days, snow water equivalent depth, and snow density). Simulated snow conditions were verified against moderate-resolution imaging spectroradiometer-derived snow cover extent and 3064 individual direct observations of snow depths. Regional variability in mean annual air temperature occurred: positive trends in general were seen in the high Andes Cordillera, and negative trends at relatively lower elevations both east and west of the Cordillera. Snow precipitation showed more heterogeneous patterns than air temperature due to the influence from atmospheric conditions, topography, and orography. Overall, for the Cordillera, much of the area north of 23°S had a decrease in the number of snow cover days, while the southern half experienced the opposite. The snow cover extent changed ∼−15% during the simulation period, mostly between the elevations of ∼3000 and 5000 m above sea level (a.s.l.). However, below 1000 m a.s.l. (in Patagonia) the snow cover extent increased. The snow properties varied over short distances both along and across the Andes Cordillera.

Greenland Ice Sheet seasonal and spatial mass variability from model simulations and GRACE (2003–2012)

Abstract: Improving the ability of regional climate models (RCMs) and ice sheet models (ISMs) to simulate spatiotemporal variations in the mass of the Greenland Ice Sheet (GrIS) is crucial for prediction of future sea level rise. While several studies have examined recent trends in GrIS mass loss, studies focusing on mass variations at sub-annual and sub-basin-wide scales are still lacking. At these scales, processes responsible for mass change are less well understood and modeled, and could potentially play an important role in future GrIS mass change. Here, we examine spatiotemporal variations in mass over the GrIS derived from the Gravity Recovery and Climate Experiment (GRACE) satellites for the January 2003–December 2012 period using a “mascon” approach, with a nominal spatial resolution of 100 km, and a temporal resolution of 10 days. We compare GRACE-estimated mass variations against those simulated by the Modèle Atmosphérique Régionale (MAR) RCM and the Ice Sheet System Model (ISSM). In order to properly compare spatial and temporal variations in GrIS mass from GRACE with model outputs, we find it necessary to spatially and temporally filter model results to reproduce leakage of mass inherent in the GRACE solution. Both modeled and satellite-derived results point to a decline (of −178.9 ± 4.4 and −239.4 ± 7.7 Gt yr−1 respectively) in GrIS mass over the period examined, but the models appear to underestimate the rate of mass loss, especially in areas below 2000 m in elevation, where the majority of recent GrIS mass loss is occurring. On an ice-sheet-wide scale, the timing of the modeled seasonal cycle of cumulative mass (driven by summer mass loss) agrees with the GRACE-derived seasonal cycle, within limits of uncertainty from the GRACE solution. However, on sub-ice-sheet-wide scales, some areas exhibit significant differences in the timing of peaks in the annual cycle of mass change. At these scales, model biases, or processes not accounted for by models related to ice dynamics or hydrology, may lead to the observed differences. This highlights the need for further evaluation of modeled processes at regional and seasonal scales, and further study of ice sheet processes not accounted for, such as the role of subglacial hydrology in variations in glacial flow.

Other papers

The effects of Antarctic iceberg calving-size distribution in a global climate model

Emerging impact of Greenland meltwater on deepwater formation in the North Atlantic Ocean

Glacial Isostatic Adjustment (GIA) in Greenland: a Review

Long-term changes of glaciers in north-western Spitsbergen

Twelve-year cyclic surging episodes at Donjek Glacier in Yukon, Canada

Glacier melting and precipitation trends detected by surface area changes in Himalayan ponds

Effects of sources, transport and post-depositional processes on levoglucosan records in southeastern Tibetan glaciers

A global assessment of the societal impacts of glacier outburst floods

Interaction of sea ice floe size, ocean eddies and sea ice melting

Arctic sea ice decline contributes to thinning lake ice trend in northern Alaska

Predictability of Arctic annual minimum sea ice patterns

Changes in summer sea ice, albedo, and portioning of surface solar radiation in the Pacific sector of Arctic Ocean during 1982-2009

Patterns of Sea-Ice Retreat in the Transition to a Seasonally Ice-Free Arctic

Sea ice leads in the Arctic Ocean: Model assessment, interannual variability and trends

Atmospheric winter response to Arctic sea ice changes in reanalysis data and model simulations

The Role of Ocean Heat Transport in the Global Climate Response to Projected Arctic Sea Ice Loss

The Role of Springtime Arctic Clouds in Determining Autumn Sea Ice Extent

Linkages between Arctic summer circulation regimes and regional sea ice anomalies

Water-mass transformation by sea ice in the upper branch of the Southern Ocean overturning

A review of recent changes in Southern Ocean sea ice, their drivers and forcings

About the consistency between Envisat and CryoSat-2 radar freeboard retrieval over Antarctic sea ice

Monitoring surface deformation over permafrost with an improved SBAS-InSAR algorithm: With emphasis on climatic factors modeling

Permafrost Meta-Omics and Climate Change

Carbon loss and chemical changes from permafrost collapse in the northern Tibetan Plateau

The Effects of Climate Change on Seasonal Snowpack and the Hydrology of the Northeastern and Upper Midwest, U.S.

Characterizing the extreme 2015 snowpack deficit in the Sierra Nevada (USA) and the implications for drought recovery

Effect of snow grain shape on snow albedo

The Andes Cordillera. Part II: Rio Olivares Basin snow conditions (1979–2014), central Chile

Design of a scanning laser meter for monitoring the spatio-temporal evolution of snow depth and its application in the Alps and in Antarctica

Decreasing Spatial Dependence in Extreme Snowfall in the French Alps since 1958 under Climate Change

A snow climatology of the Andes Mountains from MODIS snow cover data

Spatiotemporal Snowfall Variability in the Lake Michigan Region: How is Warming Affecting Wintertime Snowfall?

Posted in Global warming effects | Leave a Comment »

New research – climate change impacts on biosphere (July 22, 2016)

Posted by Ari Jokimäki on July 22, 2016

Some of the latest papers on climate change impacts on biosphere are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Rapid climate-driven loss of breeding habitat for Arctic migratory birds

Abstract: Millions of birds migrate to and from the Arctic each year, but rapid climate change in the High North could strongly affect where species are able to breed, disrupting migratory connections globally. We modelled the climatically suitable breeding conditions of 24 Arctic specialist shorebirds and projected them to 2070 and to the mid-Holocene climatic optimum, the world’s last major warming event ~6000 years ago. We show that climatically suitable breeding conditions could shift, contract and decline over the next 70 years, with 66–83% of species losing the majority of currently suitable area. This exceeds, in rate and magnitude, the impact of the mid-Holocene climatic optimum. Suitable climatic conditions are predicted to decline acutely in the most species rich region, Beringia (western Alaska and eastern Russia), and become concentrated in the Eurasian and Canadian Arctic islands. These predicted spatial shifts of breeding grounds could affect the species composition of the world’s major flyways. Encouragingly, protected area coverage of current and future climatically suitable breeding conditions generally meets target levels; however, there is a lack of protected areas within the Canadian Arctic where resource exploitation is a growing threat. Given that already there are rapid declines of many populations of Arctic migratory birds, our results emphasize the urgency of mitigating climate change and protecting Arctic biodiversity.

Diverse growth trends and climate responses across Eurasia’s boreal forest

Abstract: The area covered by boreal forests accounts for ~16% of the global and 22% of the Northern Hemisphere landmass. Changes in the productivity and functioning of this circumpolar biome not only have strong effects on species composition and diversity at regional to larger scales, but also on the Earth’s carbon cycle. Although temporal inconsistency in the response of tree growth to temperature has been reported from some locations at the higher northern latitudes, a systematic dendroecological network assessment is still missing for most of the boreal zone. Here, we analyze the geographical patterns of changes in summer temperature and precipitation across northern Eurasia >60 °N since 1951 AD, as well as the growth trends and climate responses of 445 Pinus, Larix and Picea ring width chronologies in the same area and period. In contrast to widespread summer warming, fluctuations in precipitation and tree growth are spatially more diverse and overall less distinct. Although the influence of summer temperature on ring formation is increasing with latitude and distinct moisture effects are restricted to a few southern locations, growth sensitivity to June–July temperature variability is only significant at 16.6% of all sites (p ≤ 0.01). By revealing complex climate constraints on the productivity of Eurasia’s northern forests, our results question the a priori suitability of boreal tree-ring width chronologies for reconstructing summer temperatures. This study further emphasizes regional climate differences and their role on the dynamics of boreal ecosystems, and also underlines the importance of free data access to facilitate the compilation and evaluation of massively replicated and updated dendroecological networks.

Air pollutants degrade floral scents and increase insect foraging times

Abstract: Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

Climate change and habitat conversion favour the same species

Abstract: Land-use change and climate change are driving a global biodiversity crisis. Yet, how species’ responses to climate change are correlated with their responses to land-use change is poorly understood. Here, we assess the linkages between climate and land-use change on birds in Neotropical forest and agriculture. Across > 300 species, we show that affiliation with drier climates is associated with an ability to persist in and colonise agriculture. Further, species shift their habitat use along a precipitation gradient: species prefer forest in drier regions, but use agriculture more in wetter zones. Finally, forest-dependent species that avoid agriculture are most likely to experience decreases in habitable range size if current drying trends in the Neotropics continue as predicted. This linkage suggests a synergy between the primary drivers of biodiversity loss. Because they favour the same species, climate and land-use change will likely homogenise biodiversity more severely than otherwise anticipated.

Climate adaptation is not enough: warming does not facilitate success of southern tundra plant populations in the high Arctic

Abstract: Rapidly rising temperatures are expected to cause latitudinal and elevational range shifts as species track their optimal climate north and upward. However, a lack of adaptation to environmental conditions other than climate – for example photoperiod, biotic interactions, or edaphic conditions – might limit the success of immigrants in a new location despite hospitable climatic conditions. Here we present one of the first direct experimental tests of the hypothesis that warmer temperatures at northern latitudes will confer a fitness advantage to southern immigrants relative to native populations. As rates of warming in the Arctic are more than double the global average, understanding the impacts of warming in Arctic ecosystems is especially urgent. We established experimentally warmed and non-warmed common garden plots at Alexandra Fiord, Ellesmere Island in the Canadian High Arctic with seeds of two forb species (Oxyria digyna and Papaver radicatum) originating from 3-5 populations at different latitudes across the Arctic. We found that plants from the local populations generally had higher survival and obtained a greater maximum size than foreign individuals, regardless of warming treatment. Phenological traits varied with latitude of the source population, such that southern populations demonstrated substantially delayed leaf-out and senescence relative to northern populations. Our results suggest that environmental conditions other than temperature may influence the ability of foreign populations and species to establish at more northerly latitudes as the climate warms, potentially leading to lags in northward range shifts for some species.

Short-term climate change manipulation effects do not scale up to long-term legacies: Effects of an absent snow cover on boreal forest plants

Abstract: 1.Despite time lags and non-linearity in ecological processes, the majority of our knowledge about ecosystem responses to long-term changes in climate originates from relatively short-term experiments.

2.We utilized the longest ongoing snow removal experiment in the world and an additional set of new plots at the same location in northern Sweden to simultaneously measure the effects of long-term (11 winters) and short-term (1 winter) absence of snow cover on boreal forest understorey plants, including effects on root growth and phenology.

3.Short-term absence of snow reduced vascular plant cover in the understorey by 42%, reduced fine root biomass by 16%, reduced shoot growth by up to 53%, and induced tissue damage on two common dwarf shrubs. In the long-term manipulation, more substantial effects on understorey plant cover (92% reduced) and standing fine root biomass (39% reduced) were observed, whereas other response parameters, such as tissue damage, were observed less. Fine root growth was generally reduced, and its initiation delayed by c. 3 (short-term) to 6 weeks (long-term manipulation).

4.Synthesis We show that one extreme winter with a reduced snow cover can already induce ecologically significant alterations. We also show that long-term changes were smaller than suggested by an extrapolation of short-term manipulation results (using a constant proportional decline). In addition, some of those negative responses, such as frost damage and shoot growth, were even absolutely stronger in the short-term compared to the long-term manipulation. This suggests adaptation or survival of only those individuals that are able to cope with these extreme winter conditions, and that the short-term manipulation alone would over-predict long-term impacts. These results highlight both the ecological importance of snow cover in this boreal forest, and the value of combining short- and long-term experiments side by side in climate change research.

Other papers

Observed forest sensitivity to climate implies large changes in 21st century North American forest growth

An ecoregion assessment of projected tree species vulnerabilities in western North America through the 21st century

A risk-benefit model to simulate vegetation spring onset in response to multi-decadal climate variability: Theoretical basis and applications from the field to the Northern Hemisphere

Contrasting effects of summer and winter warming on body mass explain population dynamics in a food-limited Arctic herbivore

Vulnerability of stream community composition and function to projected thermal warming and hydrologic change across ecoregions in the western United States

Effects of permafrost thaw on nitrogen availability and plant-soil interactions in a boreal Alaskan lowland

Explaining inter-annual variability of gross primary productivity from plant phenology and physiology

Realized climate niche breadth varies with population trend and distribution in North American birds

Tracking lags in historical plant species’ shifts in relation to regional climate change

Multiple cues influence multiple traits in the phenotypically plastic melanization of the cabbage white butterfly

Richer histories for more relevant policies: 42 years of tree cover loss and gain in Southeast Sulawesi, Indonesia

Tracking the long-term responses of diatoms and cladocerans to climate warming and human influences across lakes of the Ring of Fire in the Far North of Ontario, Canada

Exposure to a heat wave under food limitation makes an agricultural insecticide lethal: a mechanistic laboratory experiment

Assessing European ecosystem stability to drought in the vegetation growing season

Phosphorus feedbacks may constrain tropical ecosystem responses to changes in atmospheric CO2 and climate

Simulated annual changes in plant functional types and their responses to climate change on the northern Tibetan Plateau

Earth science data records of global forest cover and change: Assessment of accuracy in 1990, 2000, and 2005 epochs

Climate change: consequences on the pollination of grasses in Perugia (Central Italy). A 33-year-long study

Tree demography dominates long-term growth trends inferred from tree rings

Advanced long-term bird banding and climate data mining in spring confirm passerine population declines for the Northeast Chinese-Russian flyway

Thermal growth potential of Atlantic cod by the end of the 21st century

Fern species richness and abundance are indicators of climate change on high-elevation islands: evidence from an elevational gradient on Tahiti (French Polynesia)

Achieving climate connectivity in a fragmented landscape

Global change and ecosystem connectivity: How geese link fields of central Europe to eutrophication of Arctic freshwaters

Herbivory and nutrient limitation protect warming tundra from lowland species’ invasion and diversity loss

Impacts of warming and elevated CO2 on a semi-arid grassland are non-additive, shift with precipitation, and reverse over time

Changes in Sahelian annual vegetation growth and phenology since 1960: A modeling approach

Growth and carbon relations of mature Picea abies trees under five years of free air CO2 enrichment

Assessment and prediction of the first-flowering dates for the major fruit trees in Korea using a multi-RCM ensemble

Dynamically downscaling predictions for deciduous tree leaf emergence in California under current and future climate

Infection risk decreases with increasing mismatch in host and pathogen environmental tolerances

Heat resistance throughout ontogeny: body size constrains thermal tolerance

Increased autumn rainfall disrupts predator-prey interactions in fragmented boreal forests

Bivalve aquaculture-environment interactions in the context of climate change

Flawed citation practices facilitate the unsubstantiated perception of a global trend toward increased jellyfish blooms

Posted in Global warming effects | 2 Comments »

New research, June 17, 2016

Posted by Ari Jokimäki on June 17, 2016

After this, there will be a few weeks break in these posts. New research posts will then resume possibly in a new form – stay tuned.

Some new papers from last few days:

Investigating the pace of temperature change and its implications over the twenty-first century

Threshold Sensitivity of Shallow Arctic Lakes and Sub-lake Permafrost to Changing Winter Climate

Variability in the sensitivity among model simulations of permafrost and carbon dynamics in the permafrost region between 1960 and 2009

Longer thaw seasons increase nitrogen availability for leaching during fall in tundra soils (open access)

Spatial patterns and frequency of unforced decadal-scale changes in global mean surface temperature in climate models

Uncertainties in the attribution of greenhouse gas warming and implications for climate prediction

The linkage between stratospheric water vapor and surface temperature in an observation-constrained coupled general circulation model

A new perspective on global mean sea-level (GMSL) acceleration

The analysis of Last Interglacial (MIS 5e) relative sea-level indicators: Reconstructing sea-level in a warmer world

Organic matter losses in German Alps forest soils since the 1970s most likely caused by warming

Reversal of global atmospheric ethane and propane trends largely due to US oil and natural gas production

A high resolution record of Greenland mass balance

Derivation and validation of supraglacial lake volumes on the Greenland Ice Sheet from high-resolution satellite imagery

Revisiting Extreme Storms of the Past 100 Years for Future Safety of Large Water Management Infrastructures (open access)

Evidence of rising and poleward shift of storm surge in western North Pacific in recent decades

Role of ocean evaporation in California droughts and floods

Effects of a Warming Climate on Daily Snowfall Events in the Northern Hemisphere

Can significant trends be detected in surface air temperature and precipitation over South America in recent decades?

On the ambiguous nature of the 11-year solar cycle signal in upper stratospheric ozone

Improved Retrieval of Cloud Liquid Water from CloudSat and MODIS

Albedo climatology for European land surfaces retrieved from AVHRR data (1990-2014) and its spatial and temporal analysis from green–up to vegetation senescence

Using satellite-derived optical thickness to assess the influence of clouds on terrestrial carbon uptake

An observationally based global band-by-band surface emissivity dataset for climate and weather simulations

Decadal to centennial variability of salinity in the Baltic Sea

Highest drought sensitivity and lowest resistance to growth suppression are found in the range core of the tree Fagus sylvatica L. not the equatorial range edge (open access)

Biodiversity in marine invertebrate responses to acute warming revealed by a comparative multi-omics approach

The effects of elevated CO2 and eutrophication on surface elevation gain in a European saltmarsh

How will climate change affect the vegetation cycle over France ? A generic modeling approach

Micro-climatic controls and warming effects on flowering time in alpine snowbeds

Spring bloom onset in the Nordic Seas (open access)

The influence of climate variability on internal migration flows in South Africa

Regional organisations and climate change adaptation in small island developing states

Should we build wind farms close to load or invest in transmission to access better wind resources in remote areas? A case study in the MISO region

Paradigms and poverty in global energy policy: research needs for achieving universal energy access (open access)

Climatic Tipping Points and Optimal Fossil-Fuel Use

Likelihood of climate change pathways under uncertainty on fossil fuel resources availability

A quantitative description of state-level taxation of oil and gas production in the continental U.S

Towards a low carbon growth in Mexico: Is a double dividend possible? A dynamic general equilibrium assessment

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New research, June 13, 2016

Posted by Ari Jokimäki on June 13, 2016

Some new papers from last few days:

Sensitivity of Arctic warming to sea-ice concentration

New visualizations highlight new information on the contrasting Arctic and Antarctic sea-ice trends since the late 1970s

Conventional intensive logging promotes loss of organic carbon from the mineral soil

Bergmann’s rule in the oceans? Temperature strongly correlates with global interspecific patterns of body size in marine mammals

Quantifying the drivers of ocean-atmosphere CO2 fluxes

Climate impacts on multidecadal pCO2 variability in the North Atlantic: 1948–2009 (open access)

A reversal of climatic trends in the North Atlantic since 2005

Variability of Tornado Occurrence over the Continental United States since 1950

Spatial and Temporal Patterns of Drought in the Continental U.S. during the Past Century

Drought in Northeast Brazil—past, present, and future

Anthropogenic influence on the frequency of extreme temperatures in China

Fire and Climate in Mongolia (1532-2010 CE)

Increasing Trend of Pan Evaporation over Semi-Arid Loess Plateau under a Warming Climate

So, how much of the Earth’s surface is covered by rain gauges? (open access)

Century-scale causal relationships between global dry/wet conditions and the state of the Pacific and Atlantic Oceans

Future Aerosol Reductions and Widening of the Northern Tropical Belt

Recent trends and tele-connections among South and East Asian summer monsoons in a warming environment

Anomalous mid-twentieth century atmospheric circulation change over the South Atlantic compared to the last 6000 years (open access)

Tropospheric moisture in the Southwest Pacific as revealed by homogenized radiosonde data: climatology and decadal trend

Lower tropospheric mixing as a constraint on cloud feedback in a Multi-Parameter Multi-Physics Ensemble

Stratospheric Temperature Climate Data Record from Merged SSU and AMSU-A Observations

Amphibian Breeding Phenology Trends under Climate Change: Predicting the Past to Forecast the Future

Increased variance in temperature and lag effects alter phenological responses to rapid warming in a subarctic plant community

Anthropogenic-driven rapid shifts in tree distribution lead to increased dominance of broadleaf species

Assessing woody vegetation trends in Sahelian drylands using MODIS based seasonal metrics

Daytime warming lowers community temporal stability by reducing the abundance of dominant, stable species

Seagrass meadows are threatened by expected loss of peatlands in Indonesia

Climate-driven vital rates do not always mean climate-driven population

Near future pH conditions severely impact calcification, metabolism and the nervous system in the pteropod Heliconoides inflatus

On the declining relationship between tree growth and climate in the Midwest United States: the fading drought signal

Recent glacier changes in the Tien Shan observed by satellite gravity measurements

Greenland Ice Sheet influence on Last Interglacial climate: global sensitivity studies performed with an atmosphere–ocean general circulation model (open access)

An investigation into linearity with cumulative emissions of the climate and carbon cycle response in HadCM3LC (open access)

Conflict about Climate Change at the American Meteorological Society: Meteorologists’ Views on a Scientific and Organizational Controversy (open access)

Linking climate change perceptions to adaptation and mitigation action

An experimental investigation into ‘pledge and review’ in climate negotiations

Climate change and social transformations: is it time for a quantum leap?

A people‐centred perspective on climate change, environmental stress, and livelihood resilience in Bangladesh

Cost-effective electric vehicle charging infrastructure siting for Delhi (open access)

The relative importance of climate change and population growth for exposure to future extreme droughts

Future heat-related climate change impacts on tourism industry in Cyprus

Assessing the impacts of temperature variations on rice yield in China

Temperature and precipitation effects on agrarian economy in late imperial China (open access)

Posted in Adaptation & Mitigation, Climate science, Global warming effects | 2 Comments »

New research, June 6, 2016

Posted by Ari Jokimäki on June 6, 2016

Some new papers from last few days:

Isolating the Temperature Feedback Loop and Its Effects on Surface Temperature

Changes in anthropogenic carbon storage in the Northeast Pacific in the last decade

Tropical amphibians in shifting thermal landscapes under land use and climate change

Climate change impacts on wildlife in a High Arctic archipelago – Svalbard, Norway

Modelling interannual variation in the spring and autumn land surface phenology of the European forest (open access)

Disturbance and the Carbon Balance of US Forests: A Quantitative Review of Impacts from Harvests, Fires, Insects, and Droughts

Vulnerabilities of macrophytes distribution due to climate change

Melt onset over Arctic sea ice controlled by atmospheric moisture transport

Using timing of ice retreat to predict timing of fall freeze-up in the Arctic

Time forecast of a break-off event from a hanging glacier (open access)

Detection of anthropogenic influence on a summertime heat stress index

Seasonal spatial patterns of projected anthropogenic warming in complex terrain: a modeling study of the western US

Fast–slow climate dynamics and peak global warming

The Atlanto-Pacific multidecade oscillation and its imprint on the global temperature record

Tropical climate variability: interactions across the Pacific, Indian, and Atlantic Oceans

On Cold Spells in North America and Storminess in Western Europe

Interdecadal Change in Tropical Pacific Precipitation Anomaly Pattern around the late-1990s during Boreal Spring

Tropospheric circulation during the early twentieth century Arctic warming

Estimation of sampling error uncertainties in observed surface air temperature change in China

Seasonality of Global and Arctic Black Carbon Processes in the AMAP Models

Tambora 1815 as a test case for high impact volcanic eruptions: Earth system effects (open access)

1200 years of warm-season temperature variability in central Scandinavia inferred from tree-ring density (open access)

A 2000-year temperature reconstruction in the Animaqin Mountains of the Tibet Plateau, China

A refined method for calculating paleotemperatures from linear correlations in bamboo coral carbon and oxygen isotopes

Vulnerability of and risk to water resources in arid and semi-arid regions of West China under a scenario of climate change

Climate change adaptation: factors influencing Chinese smallholder farmers’ perceived self-efficacy and adaptation intent

Impacts of drought and responses of rural populations in West Africa: a systematic review

Local communities’ belief in climate change in a rural region of Sub-Saharan Africa

Modelling climate change impacts on viticultural yield, phenology and stress conditions in Europe

Interactive effects of temperature and drought on cassava growth and toxicity: implications for food security?

Visual climate change art 2005–2015: discourse and practice

Nitrogen fertilization challenges the climate benefit of cellulosic biofuels (open access)

Making sense of climate risk information: the case of future indoor climate risks in Swedish churches

Posted in Adaptation & Mitigation, Climate science, Global warming effects | Leave a Comment »

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