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Carbon Trends

State of the carbon cycle: An annual update of the global carbon budget

The Global Carbon Project will regularly update the trends of carbon quantities and global carbon budget with an annual release of the complete budget in the timeframe of July-September of each year.

Highlights in Carbon Trends
Atmospheric Emissions

Atmospheric CO2 growth
Global average atmospheric CO2 rose from 280 ppm at the start of the industrial revolution (approximately 1750) to 381 ppm in 2006.  The present concentration is the highest during the last 650,000 years and probably during the last 20 million years. 
The growth rate of global average atmospheric CO2 for 2000-2006 was 1.93 ppm y -1 (or 4.1 PgC y -1) and it was 1.5 ppm y -1 for the previous 30 years.
Land Use Changes, Sumatra

Emissions from land use change
Land use change, largely deforestation and wood harvest, has been responsible for emitting 158 PgC (1 PgC = 1 petagram or 109 metric tons of carbon) between 1850 and 2006. Annual land use change emissions continue at present at 1.5 PgC.

Fossile Fuel Emissions

Emissions from fossil fuel
Fossil fuel and cement emissions released approximately 330 PgC to the atmosphere from 1850 to 2006. Emissions increased from 7.0 PgC per year in 2000 to 8.4 PgC per year in 2006, 35% above emissions in 1990. The growth rate of emissions increased from 1.3% per year for 1990-1999 to 3.3% per year for 2000-2006.
Carbon Intensity

Carbon intensity of the economy
The carbon intensity of the global economy, after almost 100 years of continued improvements (decrease), has being on halt since 2000. The carbon intensity is the amount of carbon emitted to produce one $ of wealth.
Emission Scenarios

Fossil fuel emission trajectories
Current fossil fuel emissions are tracking the most carbon intensive scenario developed by the IPCC-SRES (A1FI-rapid economic development using a carbon intense energy system).
Regional emissions

Regional emissions
Developed countries, with less than 20% of the world’s population, are responsible for 80% of the atmospheric CO2 accumulation since 1751.
The least developed countries, with 800 million people, have contributed less than 1% yet they are the most vulnerable people to climate change.
60% of the current growth in emissions is due to China.
Natural Forest Sink

Removal by natural CO2 sinks
Natural land and ocean CO2 sinks are responsible for removing 55% (or 4.1 PgC per year) of the carbon emissions from human activities. The land removes 30% and the ocean 25%.
Southern Ocean Sink

Efficiency of CO2 natural sinks
The efficiency of natural sinks has decreased by 10% over the last 50 years (and will continue to do so in the future), implying that the longer we wait to reduce emissions, the larger the cuts needed to stabilize atmospheric CO2. Fifty years ago, for every ton of CO2 emitted to the atmosphere, natural sinks removed 600 kg. Currently, the sinks are removing only 550 kg and this amount is falling.
CONCLUSIONS

All of these changes characterize a carbon cycle that is generating stronger climate forcing and sooner than expected.

Trends and the Global Carbon Budget
Download a complete ppt presentation with the latest trends on carbon quantities and the global carbon budget. Full references are provided for all data presented. Current update includes 2006. (ppt, 2.88 Mb) (pdf, 1.45 Mb)

Data
Data and data sources for the complete global carbon budget are available from:
http://lgmacweb.env.uea.ac.uk/lequere/co2/carbon_budget.htm

Key Readings

Latest results:
Canadell JG, Corinne Le Quéré, Michael R. Raupach, Christopher B. Field, Erik T. Buitenhuis, Philippe Ciais, Thomas J. Conway, RA. Houghton, Gregg Marland (2007) A changing global carbon cycle: Faster atmospheric CO2 growth and weakening natural sinks. PNAS, October early edition (open access after 18:00 GMT - 22 October, 2007).

Corinne Le Quéré, Christian Rödenbeck, Erik T Buitenhuis, Thomas J Conway, Ray Langensfelds, Antony Gomez, Casper Labuschangne, Michel Ramonet, Takakiyo Nakazawa, Nicolas Metzl, Nathan P Gillett and Martin Heimann. (2007) Saturations of the Southern Ocean CO2 sink due to recent climate change. Science. 22 June 2007: Vol. 316. no. 5832, pp. 1735 - 1738

Raupach MR, G. Marland, P. Ciais, C. LeQuere, J.G. Canadell, C.B. Field (2007) Global and regional drivers of accelerating CO2 emissions. PNAS 14: 10288-10293 Link to PNAS Article

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

Latest Synthesis papers:
Canadell JG et al. (2007). 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 Link to chapter (pdf, 1Mb)

Doney and Schimel (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)

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