Trends in the sources and sinks of carbon dioxide


Efforts to control climate change require the stabilization of atmospheric CO2 concentrations. This can only be achieved through a drastic reduction of global CO2 emissions. Yet fossil fuel emissions increased by 29% between 2000 and 2008, in conjunction with increased contributions from emerging economies, from the production and international trade of goods and services, and from the use of coal as a fuel source. In contrast, emissions from land-use changes were nearly constant. 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. Changes in the CO2 sinks are highly uncertain, but they could have a significant influence on future atmospheric CO2 levels. It is therefore crucial to reduce the uncertainties.

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Figure 1: Fossil fuel CO2 and per-capita emissions since 1990.
Figure 2: Components of the global CO2 budget.
Figure 3: Trends in the observed partial pressure of CO2 for ocean minus air, for 1981–2007.


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The annual update and analyses of the global carbon budget are a collaborative effort of the Global Carbon Project, a joint project of the Earth System Science Partnership, contributed to by an international consortium of scientists. We thank C. Rödenbeck, A. Mouchet, R. Keeling and N. Gruber for comments on this manuscript, and C. Enright and E. T. Buitenhuis for modelling support. Many of the observations and modelling analyses were supported by funding agencies in the European Union (CARBOOCEAN and the Natural Environment Research Council's QUEST programme), the United States (the National Science Foundation, NASA, the National Oceanic and Atmospheric Administration and the Office of Science of the Department of Energy), Australia and Brazil.

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C.L.Q., M.R.R., J.G.C., G.M., R.A.H., P.C. and P. Friedlingstein conceived and designed the global CO2 budget. G.M. estimated the fossil fuel emissions and G.P.P. estimated the emissions from the production and international trade of goods and services. R.A.H., G.R.v.d.W. and J.T.R. estimated LUC emissions and were helped by J.G.C., J.P.O. and J.I.H. in their interpretation. S.S., N.V., P.C., P. Foster, P. Friedlingstein, C.H., P.E.L., M.R.L., F.I.W. and I.C.P. designed and performed the land model simulations and were helped by S.W.R. in their interpretation. C.L.Q., L.B., S.C.D., J.M. and J.L.S. designed and performed the ocean model simulations. R.A.F., N.M., U.S. and T.T. provided and analysed the ocean CO2 observations, and T.J.C. provided and analysed the atmospheric CO2 observations. K.G. provided updated atmospheric CO2 inversions. M.R.R. and C.L.Q. computed and analysed the trends in sources, sinks and airborne fraction. S.S., P. Friedlingstein and C.L.Q. analysed the residual with the help of all authors. All authors co-wrote the paper.

Corinne Le Quéré1, 2, Michael R. Raupach 3, Josep G. Canadell 3, Gregg Marland4, Laurent Bopp5, Philippe Ciais5, Thomas J. Conway6, Scott C. Doney7, Richard A. Feely8, Pru Foster9, Pierre Friedlingstein5, 9, Kevin Gurney10, Richard A. Houghton11, Joanna I. House9, Chris Huntingford12, Peter E. Levy13, Mark R. Lomas14, Joseph Majkut15, Nicolas Metzl16, Jean P. Ometto17, Glen P. Peters18, I. Colin Prentice9, James T. Randerson19, Steven W. Running20, Jorge L. Sarmiento15, Ute Schuster1, Stephen Sitch21, Taro Takahashi22, Nicolas Viovy5, Guido R. van der Werf23, F. Ian Woodward14

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Correspondence to Corinne Le Quéré.

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Le Quéré, C., Raupach, M., Canadell, J. et al. Trends in the sources and sinks of carbon dioxide. Nature Geosci 2, 831–836 (2009).

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