The global carbon budget 1959 - 2011

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the climate policy process, and project future climate change. Present-day analysis requires the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. This paper describes datasets and a methodology developed by the global carbon cycle science community to quantify all major components of the global carbon budget, including their uncertainties. Changes compared to previous estimates, consistency within and among components, and methodology and data limitations are discussed.

Based on energy statistics, the authors estimate that the global emissions of CO2 from fossil fuel combustion and cement production were 9.5 ± 0.5 petagram (Pg, 1012 kilogram) carbon in 2011, 3.0 percent above 2010 levels. The authors project these emissions will increase by 2.6 percent (1.9–3.5 percent) in 2012 based on projections of Gross World Product and recent changes in the carbon intensity of the economy. Global net CO2 emissions from Land-Use Change, including deforestation, are more difficult to update annually because of data availability, but combined evidence from land cover change data, fire activity in regions undergoing deforestation and models suggests those net emissions were 0.9 ± 0.5 Pg carbon in 2011. The global atmospheric CO2 concentration is measured directly and reached 391.38 ± 0.13 parts per million (ppm) at the end of year 2011, increasing 1.70 ± 0.09 ppm or 3.6 ± 0.2 Pg carbon in 2011.

Estimates from four ocean models suggest that the ocean CO2 sink was 2.6 ± 0.5 Pg carbon in 2011, implying a global residual terrestrial CO2 sink of 4.1 ± 0.9 Pg carbon per year. All uncertainties are reported as ±1 sigma (68% confidence assuming Gaussian error distributions that the real value lies within the given interval), reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. This paper is intended to provide a baseline to keep track of annual carbon budgets in the future.

Authors

C. Le Quéré, R. J. Andres, T. Boden, T. Conway, R. A. Houghton, J. I. House, G. Marland, G. P. Peters, G. van der Werf, A. Ahlström, R. M. Andrew, L. Bopp, J. G. Canadell, P. Ciais, S. C. Doney, C. Enright, P. Friedlingstein, C. Huntingford, A. K. Jain, C. Jourdain, E. Kato, R. F. Keeling, K. Klein Goldewijk, S. Levis, P. Levy, M. Lomas, B. Poulter, M. R. Raupach, J. Schwinger, S. Sitch, B. D. Stocker, N. Viovy, S. Zaehle, and N. Zeng

Specifications

Publication title
The global carbon budget 1959–2011
Publication date
3 December 2012
Publication type
Publicatie
Magazine
Earth System Science Data
Product number
1011