AGW Observer

Papers on global carbon cycle


This list contains papers on global carbon cycle, with emphasis on observations. 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 14, 2010): Tans et al. (1990) added.
UPDATE (January 5, 2010): Knorr (2009) added.
UPDATE (December 9, 2009): Le Quéré et al. (2009) added.
UPDATE (December 4, 2009): Sundquist (1993) added.
UPDATE (September 29, 2009): Section “Carbon cycle in past climate” added, Elsig et al. (2009) added (thanks to John Cook for pointing out this paper, see discussion section below), and Hughen et al. (2004) added.

Carbon cycle in modern climate

Is the airborne fraction of anthropogenic CO2 emissions increasing? – Knorr (2009) “This study re-examines the available atmospheric CO2 and emissions data including their uncertainties. It is shown that with those uncertainties, the trend in the airborne fraction since 1850 has been 0.7 ± 1.4% per decade, i.e. close to and not significantly different from zero. The analysis further shows that the statistical model of a constant airborne fraction agrees best with the available data if emissions from land use change are scaled down to 82% or less of their original estimates. Despite the predictions of coupled climate-carbon cycle models, no trend in the airborne fraction can be found.” [Full text]

Trends in the sources and sinks of carbon dioxide – Le Quéré et al. (2009) “Between 1959 and 2008, 43% of each year’s CO2 emissions remained in the atmosphere on average; the rest was absorbed by carbon sinks on land and in the oceans. In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability.”

Understanding and managing the global carbon cycle – Birdsey et al. (2009) A brief review article that focuses on USA situation but lot of it is also globally relevant. [Link to PDF]

Interannual variability of the global carbon cycle (1992–2005) inferred by inversion of atmospheric CO2 and δ13CO2 measurements – Rayner et al. (2008) “We present estimates of the surface sources and sinks of CO2 for 1992–2005 deduced from atmospheric inversions. … The results suggest that interannual variability is dominated by the tropical land. Statistically significant variability in the tropical Pacific supports recent ocean modeling studies in that region. The northern land also shows significant variability.”

Understanding and managing the global carbon cycle – Grace (2004) A review article. “There is broad agreement among the results from these methods: carbon sinks are currently found in tropical, temperate and boreal forests as well as the ocean. … However, on a global scale the effect of the terrestrial sinks (absorbing 2–3 billion tonnes of carbon per year) is largely offset by deforestation in the tropics (losing 1–2 billion tonnes of carbon per year).” [Link to PDF]

Carbon cycling in earth systems—a soil science perspective – Janzen (2004) A review article. “The carbon cycle binds together earth’s ecosystems and their inhabitants. My intent is to review the global carbon cycle, examine how humans have modified it, and contemplate (from a soil science bias) the new questions that await us on a changing earth. These thoughts are proffered, not to propose a way forward, but to invite conversation about opportunities that await us.” [Link to PDF]

Satellite Data Help Predict Terrestrial Carbon Sinks – Potter et al. (2003) “Accurate estimates of how much CO2 ecosystems can absorb will be fundamental to successful systems of international carbon accounting. NASA’s Terra satellite platform, with the moderate resolution imaging spectroradiometer (MODIS) instrument on board, provides a new era of observations for carbon cycle assessments. Direct input of satellite vegetation index “greenness” data from the MODIS sensor into ecosystem simulation models can be used to estimate spatial variability in monthly net primary production (NPP), biomass accumulation, and litter fall inputs to soil carbon pools.”

Towards robust regional estimates of CO2 sources and sinks using atmospheric transport models – Gurney et al. (2002) “Here we report estimates of surface–atmosphere CO2 fluxes from an intercomparison of atmospheric CO2 inversion models (the TransCom 3 project), which includes 16 transport models and model variants. … Overall, carbon fluxes integrated over latitudinal zones are strongly constrained by observations in the middle to high latitudes. Further significant constraints to our understanding of regional carbon fluxes will therefore require improvements in transport models and expansion of the CO2 observation network within the tropics.”

The Global Carbon Cycle: A Test of Our Knowledge of Earth as a System – Falkowski et al. (2000) A review article. “Our knowledge of the carbon cycle within the oceans, terrestrial ecosystems, and the atmosphere is sufficiently extensive to permit us to conclude that although natural processes can potentially slow the rate of increase in atmospheric CO2, there is no natural “savior” waiting to assimilate all the anthropogenically produced CO2 in the coming century.” [Link to PDF]

Global and hemispheric CO2 sinks deduced from changes in atmospheric O2 concentration – Keeling et al. (1996) “The data are consistent with a budget in which, for the 1991–94 period, the global oceans and the northern land biota each removed the equivalent of approximately 30% of fossil-fuel CO2 emissions, while the tropical land biota as a whole were not a strong source or sink.”

Terrestrial ecosystems and the carbon cycle – Schimel (1995) A review article (?) “The terrestrial biosphere plays an important role in the global carbon cycle. In the 1994 Intergovernmental Panel Assessment on Climate Change (IPCC), an effort was made to improve the quantification of terrestrial exchanges and potential feedbacks from climate, changing CO2, and other factors; this paper presents the key results from that assessment, together with expanded discussion.”

Atmospheric carbon dioxide and the ocean – Siegenthaler & Sarmiento (1993) A review article. “The ocean is a significant sink for anthropogenic carbon dioxide, taking up about a third of the emissions arising from fossil-fuel use and tropical deforestation. Increases in the atmospheric carbon dioxide concentration account for most of the remaining emissions, but there still appears to be a ‘missing sink’ which may be located in the terrestrial biosphere.” [Link to PDF]

The global carbon dioxide budget – Sundquist (1993) “The increase in atmospheric CO2 levels during the last deglaciation was comparable in magnitude to the recent historical increase. However, global CO2 budgets for these changes reflect fundamental differences in rates and in sources and sinks. The modern oceans are a rapid net CO2 sink, whereas the oceans were a gradual source during the deglaciation. Unidentified terrestrial CO2 sinks are important uncertainties in both the deglacial and recent CO2 budgets. The deglacial CO2 budget represents a complexity of long-term dynamic behavior that is not adequately addressed by current models used to forecast future atmospheric CO2 levels.” [Link to PDF]

Observational Constrains on the Global Atmospheric CO2 Budget – Tans et al. (1990) “Observed atmospheric concentrations of CO2 and data on the partial pressures of CO2 in surface ocean waters are combined to identify globally significant sources and sinks of CO2. The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO2 are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO2 in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO2. Therefore, a large amount of the CO2 is apparently absorbed on the continents by terrestrial ecosystems.”

The global carbon cycle – Post et al. (1990) “This article presents important advances in carbon-cycle research, inventories the world’s carbon reservoirs, and discusses what is known about the role of oceanic and terrestrial systems in exchanging CO{sub 2} with the atmosphere. Finally, a new global systems approach is described that shows promise in resolving current difficulties.” [Link to PDF]

Carbon cycle in past climate

Stable isotope constraints on Holocene carbon cycle changes from an Antarctic ice core – Elsig et al. (2009) “Here we present a highly resolved atmospheric 13C record for the past 11,000 years from measurements on atmospheric CO2 trapped in an Antarctic ice core. From mass-balance inverse model calculations performed with a simplified carbon cycle model, we show that the decrease in atmospheric CO2 of about 5 parts per million by volume (p.p.m.v.). The increase in 13C of about 0.25 [per mil] during the early Holocene is most probably the result of a combination of carbon uptake of about 290 gigatonnes of carbon by the land biosphere and carbon release from the ocean in response to carbonate compensation of the terrestrial uptake during the termination of the last ice age. The 20 p.p.m.v. increase of atmospheric CO2 and the small decrease in 13C of about 0.05 during the later Holocene can mostly be explained by contributions from carbonate compensation of earlier land-biosphere uptake and coral reef formation, with only a minor contribution from a small decrease of the land-biosphere carbon inventory.”

14C Activity and Global Carbon Cycle Changes over the Past 50,000 Years – Hughen et al. (2004) “Reconstructed 14C activities varied substantially during the last glacial period, including sharp peaks synchronous with the Laschamp and Mono Lake geomagnetic field intensity minimal and cosmogenic nuclide peaks in ice cores and marine sediments. Simulations with a geochemical box model suggest that much of the variability can be explained by geomagnetically modulated changes in 14C production rate together with plausible changes in deep-ocean ventilation and the global carbon cycle during glaciation.” [Link to PDF]

Closely related

Integrated Global Carbon Observation Theme – Ciais et al. (2004) A Strategy to Realize a Coordinated System of Integrated Global Carbon Cycle Observations.

The Global Carbon Cycle – Bolin et al. (1979) “The present publication is the result of the Workshop on the Carbon Cycle, held at Ratzeburg, Federal Republic of Germany, 2126 March 1977. The carbon cycle is the most important and most complex cycle of all, as it is the pacemaker for the other cycles which in turn codetermine flow rates in the carbon cycle.”