Global Carbon Project (GCP) Homepage

Carbon Trends

2007 update

An annual update of the
global carbon budget and trends

Contributors
Corinne Le Quéré [C.Lequere@uea.ac.uk] (University of East Anglia/British Antarctic Survey, UK), Mike Raupach [Michael.raupach@csiro.au](CSIRO, Australia), Philippe Ciais [philippe.ciais@lsce.ipsl.fr] (Commissariat a L'Energie Atomique, France), Thomas Conway [Thomas.J.Conway@noaa.gov] (NOAA, USA), Chris Field [cfield@globalecology.stanford.edu] (Carnegie Instituton of Washington, USA), Skee Houghton [rhoughton@whrc.org] (Woods Hole Research Center, USA), Gregg Marland [marlandgh@ornl.gov] (Carbon Dioxide Information Analysis Center, USA), Pep Canadell [pep.canadell@csiro.au] (CSIRO, Australia)

Launch Events and Press Releases
The new Global Carbon Budget will be launched on the 26th September 2008, simultaneously at the Paris Observatory, France, by GCP co-chair Michael Raupach (Announcement, pdf 796Kb), and at Capitol Hill, Washington, D.C., USA, by GCP Executive Director Pep Canadell (Announcement )

Press releases: GCP (pdf, 76Kb), CSIRO (pdf, 36Kb), British Antarctica (pdf,33Kb), Oak Ridge (pdf,38Kb)

How to Cite this New Update

Please cite this update as "Global Carbon Project (2008) Carbon budget and trends 2007, [www.globalcarbonproject.org, 26 September 2008]". For peer review publications, we suggest using the "Global Carbon Project (2008)" reference along with the underpinning analyses cited below in References supporting this analysis.

Highlights
Atmospheric Emissions

Atmospheric CO2 growth
Annual mean growth rate of atmospheric CO2 was 2.2 ppm per year in 2007 (up from 1.8 ppm in 2006), and above the 2.0 ppm average for the period 2000-2007. The average annual mean growth rate for the previous 20 years was about 1.5 ppm per year. This increase brought the atmospheric CO2 concentration to 383 ppm in 2007, 37% above the concentration at the start of the industrial revolution (about 280 ppm in 1750).  The present concentration is the highest during the last 650,000 years and probably during the last 20 million years. [ppm =  parts per million].

Land Use Changes, Sumatra Emissions from land use change
Land use change was responsible for estimated net emissions of 1.5 PgC per year to the atmosphere. This is largely the difference between CO2 emissions from deforestation and CO2 uptake by reforestation. Emissions for 2006 and 2007 were extrapolated from the previous 25-year trend of 1.5 PgC per year. Land use change emissions come almost exclusively from deforestation in tropical countries with an estimated 41% from South and Central America, 43% from South and Southeast Asia, and 17% from Africa. An estimated 160 PgC were emitted to the atmosphere from land use change during the period 1850-2007 [1 Pg = 1 billion tons or 1000 x million tons]. 
Fossile Fuel Emissions Emissions from fossil fuel and cement
 Emissions increased from 6.2 PgC per year in 1990 to 8.5 PgC in 2007, a 38% increase from the Kyoto reference year 1990. The growth rate of emissions was 3.5% per year for the period of 2000-2007, an almost four fold increase from 0.9% per year in 1990-1999. The actual emissions growth rate for 2000-2007 exceeded the highest forecast growth rates for the decade 2000-2010 in the emissions scenarios of the Intergovermental Panel on Climate Change, Special Report on Emissions Scenarios (IPCC-SRES). This makes current trends in emissions higher than the worst case IPCC-SRES scenario. Fossil fuel and cement emissions released approximately 348 PgC to the atmosphere from 1850 to 2007.
regionalemissions Regional fossil fuel emissions
The biggest increase in emissions has taken place in developing countries, largely in China and India, while developed countries have been growing slowly. The largest regional shift was that China passed the U.S. in 2006 to become the largest CO2 emitter, and India will soon overtake Russia to become the third largest emitter. Currently, more than half of the global emissions come from less developed countries. From a historical perspective, developing countries with 80% of the world’s population still account for only 20% of the cumulative emissions since 1751; the poorest countries in the world, with 800 million people, have contributed less than 1% of these cumulative emissions.
Carbon Intensity

Carbon intensity of the economy
After decades of improvements, the carbon intensity of the global economy, the carbon emitted per unit of Gross Domestic Product (GDP), was stalled during the period 2003-2005. This change was largely caused by China’s rapidly growing share in economic output and carbon emissions. Since 2005 China’s energy intensity (which underpins carbon intensity) has decreased (improved) by 1.2% in 2006 and 3.7% in 2007 compared to 2005 levels (according to the National Energy Administration in China).
NaturalSinks

CO2 removal by natural sinks
Natural land and ocean CO2 sinks have removed 54% (or 4.8 PgC per year) of all CO2 emitted from human activities during the period 2000-2007. The size of the natural sinks has grown in proportion to increasing atmospheric CO2. However, the efficiency of these sinks in removing CO2 has decreased by 5% over the last 50 years, and will continue to do so in the future. That is, 50 years ago, for every ton of CO2 emitted to the atmosphere, natural sinks removed 600 kg. Currently, the sinks are removing only 550 kg for every ton of CO2 emitted, and this amount is falling.

Southern Ocean Sink

Natural Ocean CO2 sinks
The global oceanic CO2 sink removed 25% of all CO2 emissions for the period 2000-2007, equivalent to an average of 2.3 PgC per year. The size of the CO2 sink in 2007 was similar to that in the previous year but lower by 0.1 PgC compared to its expected increase from atmospheric CO2 growth. This was due to the presence of a La Nina event in the equatorial Pacific. The Southern Ocean CO2 sink was higher in 2007 compared to 2006, consistent with the relatively weak winds and the low Southern Annular Mode (a circumpolar pressure oscillation between Antarctica and southern mid-latitudes). An analysis of the long term trend of the ocean sink shows a slower growth than expected of the CO2 sink over the last 20 years.

Natural Forest Sink

Natural Land CO2 sinks
Terrestrial CO2 sinks removed 29% of all anthropogenic emissions for the period 2000-2007, equivalent to an average of 2.6 PgC per year. Terrestrial ecosystems removed 2.9 PgC in 2007, down from 3.6 Pg in 2006, largely showing the high year-to-year variability of the sink. An analysis of the long term trend of the terrestrial sink shows a growing size of the CO2 sink over the last 50 years.

Conclusions

Anthropogenic CO2 emissions have been growing about four times faster since 2000 than during the previous decade, and despite efforts to curb emissions in a number of countries which are signatories of the Kyoto Protocol. Emissions from the combustion of fossil fuel and land use change reached the mark of 10 billion tones of carbon in 2007. Natural CO2 sinks are growing, but more slowly than atmospheric CO2, which has been growing at 2 ppm per year since 2000. This is 33% faster than during the previous 20 years. All of these changes characterize a carbon cycle that is generating stronger climate forcing and sooner than expected.

Presentation (ppt, pdf)
Download a complete ppt presentation with an overview of the Carbon Budget 2007
(ppt, 3.3 Mb) (pdf, 1.5 Mb)

Additional emission figures (pdf 25Kb)

Data Sources
Atmospheric CO2 concentration (Pieter Tans and Thomas Conway, NOAA/ESRL), Fossil fuel emissions (Gregg Marland, T.A. Boden, R.J. Andres, and J. Gregg, CDIAC), Emissions from land use change (Richard A. Houghton, FAO ), Ocean sink (Corinne Le Quéré).

Data Files
Data files and a complete description of data sources and calculations is availablle from: http://lgmacweb.env.uea.ac.uk/lequere/co2/carbon_budget.htm .

References supporting this analysis

Canadell JG, Corinne Le Quéré, Michael R. Raupach, Christopher B. Field, Erik T. Buitehuis, Philippe Ciais, Thomas J. Conway, RA. Houghton, Gregg Marland (2007) Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks (pdf, 1.4Mb). Proceedings of the National Academy of Science, 0702737104

Canadell JG, Raupach MR, Houghton RA (2008) Anthropogenic CO2 emissions in Africa. Biogeosciences (submitted).

Gregg JS, Andres RJ, Marland G (2008) China: Emissions pattern of the world leader in CO2 emissions from fossil fuel consumption and cement production. Geophysical Research Letters 35, L08806, doi:10.1029/2007GL032887.

Le Quéré C , Rödenbeck C, Buitenhuis ET, Conway TJ, Langensfelds R, Gomez A, Labuschangne C, Ramonet M, Nakazawa T, Metzl N, Gillett NP, Heimann M (2007) Saturations of the Southern Ocean CO2 sink due to recent climate change. Science 316, 5832: 1735-1738.

Raupach MR, G. Marland, P. Ciais, C. Quéré, J.G. Canadell, C.B. Field (2007) Global and regional drivers of accelerating CO2 emissions. Proceedings of the National Academy of Science 14: 10288-10293

Other Recent Analyses
Luyssaert S, E. -Detlef Schulze, Annett Borner, Alexander Knohl, Dominik Hessenmoller, Beverly E. Law, Philippe Ciais, John Grace (2008) Old-growth forests as global carbon sinks. Nature 455, September 2008| doi:10.1038/nature07276.

Ciais P, M. J. Schelhaas, S. Zaehle1, S. L. Piao, A. Cescatti, J. Liski, S. Luyssaert, G. Le-Maire, E.-D. Schulze, O. Bouriaud, A. Freibauer, R. Valentini, G. J. Nabuurs (2008) Carbon accumulation in European forests. Nature Geoscience 1: 425–429, doi:10.1038/ngeo233.

Compton J. Tucker, and Inez Y. Fung, Wolfgang Buermann, Benjamin R. Lintner, Charles D. Koven, Alon Angert, Jorge E. Pinzon (2007) The changing carbon cycle at Mauna Loa Observatory. Proceedings of the National Academy of Science 2007;104;4249-4254; originally published online. doi:10.1073/PNAS.0611224104.

Gurney KR, David Baker D, Rayner P, Denning S (2008) Interannual variations in continental-scale net carbon exchange and sensitivity to observing networks estimated from atmospheric CO2 inversions for the period 1980 to 2005. Global Biogeochemical Cycles 22, GB3025, doi:10.1029/2007GB003082.

Nevison CD, Natalie M. Mahowald,1,2 Scott C. Doney,3 Ivan D. Lima,3 Guido R. van der Werf,4 James T. Randerson,5 David F. Baker,3 Prasad Kasibhatla, Galen A. McKinley (2008) Contribution of ocean, fossil fuel, land biosphere, and biomass burning carbon fluxes to seasonal and interannual variability in atmospheric CO2 Global Biogeochemical Cycles 22, GB3008, doi:10.1029/2007GB003068.

Peters, W., A. Jacobson, C. Sweeney, A. Andrews, T.J., Conway, K.A., Masarie, J.B. Miller, L. Bruhwiler, G. Petron, A. Hirsch, D. Worthy, van der Werf G., Randerson J.T., Wennberg P., Krol M., Tans P.(2007) An atmospheric perspective on North American carbon dioxide exchange: CarbonTracker, Proceedings of the National Academy of Science 104: 18925-18930.

Piao S, Philippe Ciais, Pierre Friedlingstein, Philippe Peylin, Markus Reichstein, Sebastiaan Luyssaert, Hank Margolis, Jingyun Fang, Alan Barr, Anping Chen, Achim Grelle, David Y. Hollinger, Tuomas Laurila, Anders Lindroth, Andrew D. Richardson & Timo Vesala (2008) Net carbon dioxide losses of northern ecosystems in response to autumn warming Nature 451, 49-52, doi:10.1038/nature06444.

Raupach MR, Canadell JG, Le Quéré C (2008) Anthropogenic and biophysical contributions to increasing atmospheric CO2 growth rate and airborne fraction. Biogeosciences Discuss 5: 2867-2896.

Schuster U, Watson A (2007) A variable and decreasing sink for atmospheric CO2 in the North Atlantic. Journal of Geophysical Research 112, C11006, doi:10.1029/2006JC003941.

Stephens et al (2007) Weak Northern and Strong Tropical Land Carbon Uptake from Vertical Profiles of Atmospheric CO2. Science. 22 June 2007: 1732-1735 DOI: 10.1126/science.1137004.

Takahashi et al. (2008). Global sea.air CO2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effects. Deep. Sea Research, 49, 1411-1421.

Recent Synthesis
Canadell JG, Pataki D, Gifford R, Houghton RA, Lou Y, Raupach MR, Smith P, Steffen W (2007) Saturation of the terrestrial carbon sink. (pdf, 1Mb) In: Terrestrial Ecosystems in a Changing World, Canadell JG, Pataki D, Pitelka L (eds.), pp. 59-78. The IGBP Series. Springer-Verlag, Berlin Heidelberg, pp. 59-78.

Doney S, Schimel D (2007) Carbon and Climate System Coupling. Annual Review of Environment and Resources.

IPCC (2007) Chapter 7. WG1Fourth Assessment Report. Couplings Between Changes in the Climate System and Biogeochemistry (pdf, 3.12 Mb)

Heimann M, Reichstein M (2008) Terrestrial ecosystem carbon dynamics and climate feedbacks. Nature 45, January 2008|doi:10.1038/nature06591.

Houghton RA (2007) Balancing the global carbon budget. Annual Review of Earth and Planetary Sciences 35: 313-347