Recent Carbon Trends and the Global Carbon Budget updated to 2006 GCP-Global Carbon Budget team: Pep Canadell, Philippe Ciais, Thomas Conway, Chris Field, Corinne Le Quéré, Skee Houghton, Gregg Marland, Mike Raupach, Erik Buitenhuis, Nathan Gillett Last update: 15 November 2007

Outline Recent global carbon trends (2000-2006) The perturbation of the global carbon budget (1850-2006) The declining efficiency of natural CO2 sinks Attribution of the recent acceleration of atmospheric CO2 Conclusions and implications for climate change

Recent global carbon trends 1. Recent global carbon trends

Anthropogenic C Emissions: Land Use Change Tropical deforestation 13 Million hectares each year Borneo, Courtesy: Viktor Boehm 2000-2005 Tropical Americas 0.6 Pg C y-1 Tropical Asia 0.6 Pg C y-1 Tropical Africa 0.3 Pg C y-1 1.5 Pg C y-1 FAO-Global Resources Assessment 2005; Canadell et al. 2007, PNAS

Anthropogenic C Emissions: Land Use Change Carbon Emissions from Tropical Deforestation SUM 2000-2006 1.5 Pg C y-1 (16% total emissions) 1.80 1.60 Africa 1.40 Latin America 1.20 S. & SE Asia Pg C yr-1 1.00 0.80 0.60 0.40 0.20 Notice that for the first time in 50 years, emissions from tropical Latin American are similar to those from South and Southeast Asia. 0.00 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Houghton, unpublished

Anthropogenic C Emissions: Fossil Fuel 2006 Fossil Fuel: 8.4 Pg C [2006-Total Anthrop. Emissions:8.4+1.5 = 9.9 Pg] 1850 1870 1890 1910 1930 1950 1970 1990 2010 1990 - 1999: 1.3% y-1 2000 - 2006: 3.3% y-1 Raupach et al. 2007, PNAS; Canadell et al 2007, PNAS

Trajectory of Global Fossil Fuel Emissions SRES (2000) growth rates in % y -1 for 2000-2010: A1B: 2.42 A1FI: 2.71 A1T: 1.63 A2: 2.13 B1: 1.79 B2: 1.61 2006 2005 Observed 2000-2006 3.3% Current emissions are tracking above the most intense fossil fuel emission scenario established by the IPCC Special Report on Emissions Scenarios-SRES (2000), A1FI (A1 Fossil Fuel intensive); and moving rapidly away from low stabilization scenarios, eg, 450 ppm. Scenarios trends are averages across all models available for each scenario class. Since this publication, global fossil fuel emissions have been revised and used in Canadell et al. 2007, PNAS. Red dots indicate the revised and updated numbers for 2005 and 2006 respectively. Raupach et al. 2007, PNAS

Carbon Intensity of the Global Economy Kg Carbon Emitted to Produce 1 $ of Wealth Photo: CSIRO Carbon intensity (KgC/US$) Current emissions are tracking above the most intense fossil fuel scenario established by the IPCC SRES (2000), A1FI- A1 Fossil Fuel intensive; and moving away from stabilization scenarios of 450 ppm and 650 ppm. 1960 1970 1980 1990 2000 2006 Canadell et al. 2007, PNAS

Drivers of Anthropogenic Emissions 1.5 1.5 1.5 World 1.4 1.4 1.4 1.3 1.3 1.3 1.2 1.2 1.2 Population Wealth = per capita GDP 1.1 1.1 1.1 Carbon intensity of GDP Factor (relative to 1990) 1 1 1 0.9 0.9 0.9 0.8 F (emissions) Emissions 0.8 0.8 0.7 P (population) 0.7 0.7 Carbon intensity of the global economy has stopped decreasing after decades of doing so. The lack of improvement (decrease) has been maintained since 2000 to 2006. This implies that relatively more global wealth is produced by using more carbon intensive energy systems than we did in the past. The carbon intensity of the economy is the amount of C emissions required to produce 1$ of wealth (GDP-Gross Domestic Product at the country level, or Gross World Product if referred globaly) g = G/P 0.6 0.6 0.6 h = F/G 0.5 0.5 0.5 1980 1985 1990 1995 2000 2005 1980 1980 Raupach et al 2007, PNAS

Drivers of Regional CO2 Emissions Notice that countries/regions such as Japan, China, D2 and D3 are showing little or no sing of improving (decreasing) the carbon intensity of their economies over the last few years. D1-developed countries other than USA, and Japan D2-developing countries D3-least developed countries Raupach et al 2007, PNAS

Anthropogenic C Emissions: Regional Contributions 100% D3-Least Developed Countries 80% D2-Developing Countries 60% India 40% China FSU 20% D1-Developed Countries Japan 20% of the population (developed world) is responsible for 80% of the cumulative carbon emissions since 1751. China is responsible for 60% of the growth in current emissions. Most astonishing in this figure is what you don’t see: Least developed countries don’t even show in the carbon columns yet they represent more than 800 million people who are the most vulnerable to climate change. EU 0% USA Cumulative Emissions [1751-2004] Flux in 2004 Flux Growth in 2004 Population in 2004 Raupach et al. 2007, PNAS

Atmospheric CO2 Concentration Year 2006 Atmospheric CO2 concentration: 381 ppm 35% above pre-industrial 1850 1870 1890 1910 1930 1950 1970 1990 2010 [CO2] 2000 - 2006: 1.9 ppm y-1 1970 – 1979: 1.3 ppm y-1 1980 – 1989: 1.6 ppm y1 1990 – 1999: 1.5 ppm y-1 NOAA 2007; Canadell et al. 2007, PNAS

The perturbation of the global carbon cycle (1850-2006) 2. The perturbation of the global carbon cycle (1850-2006)

Perturbation of Global Carbon Budget (1850-2006) 2000-2006 deforestation Source tropics extra-tropics 1.5 CO2 flux (Pg C y-1) Sink Time (y) Le Quéré, unpublished; Canadell et al. 2007, PNAS

Perturbation of Global Carbon Budget (1850-2006) 2000-2006 fossil fuel emissions 7.6 Source deforestation 1.5 CO2 flux (Pg C y-1) Sink Time (y) Le Quéré, unpublished; Canadell et al. 2007, PNAS

Perturbation of Global Carbon Budget (1850-2006) 2000-2006 fossil fuel emissions 7.6 Source deforestation 1.5 CO2 flux (Pg C y-1) Sink Time (y) Le Quéré, unpublished; Canadell et al. 2007, PNAS

Perturbation of Global Carbon Budget (1850-2006) 2000-2006 fossil fuel emissions 7.6 Source deforestation 1.5 CO2 flux (Pg C y-1) atmospheric CO2 4.1 Sink Time (y) Le Quéré, unpublished; Canadell et al. 2007, PNAS

Perturbation of Global Carbon Budget (1850-2006) 2000-2006 fossil fuel emissions 7.6 Source deforestation 1.5 CO2 flux (Pg C y-1) atmospheric CO2 4.1 Sink ocean 2.2 Time (y) Le Quéré, unpublished; Canadell et al. 2007, PNAS

Perturbation of Global Carbon Budget (1850-2006) 2000-2006 fossil fuel emissions 7.6 Source deforestation 1.5 CO2 flux (Pg C y-1) atmospheric CO2 4.1 Sink land 2.8 ocean 2.2 Time (y) Le Quéré, unpublished; Canadell et al. 2007, PNAS

Perturbation of the Global Carbon Budget (1959-2006) CO2 flux (Pg CO2 y-1) Carbon flux (Pg C y-1) Carbon intensity (KgC/US$) Sink Source Time (y) Canadell et al. 2007, PNAS

The declining efficiency of natural sinks 3. The declining efficiency of natural sinks

Partition of Anthropogenic Carbon Emissions into Sinks [2000-2006] 45% of all CO2 emissions accumulated in the atmosphere Atmosphere The Airborne Fraction The fraction of the annual anthropogenic emissions that remains in the atmosphere 55% were removed by natural sinks Ocean removes _ 24% Land removes _ 30% Canadell et al. 2007, PNAS

Factors that Influence the Airborne Fraction The rate of CO2 emissions. The rate of CO2 uptake and ultimately the total amount of C that can be stored by land and oceans: Land: CO2 fertilization effect, soil respiration, N deposition fertilization, forest regrowth, woody encroachment, … Oceans: CO2 solubility (temperature, salinity),, ocean currents, stratification, winds, biological activity, acidification, … Canadell et al. 2007, Springer; Gruber et al. 2004, Island Press

Time Dynamics of the Airborne Fraction The observed trend in Airborne Fraction was +0.25% per year (p = 0.89) from 1959-to 2006, implying a decline in the efficiency of natural sinks of 10% Distribution (fraction) 1960 1970 1980 1990 2000 time Fifty years ago, for every tonne of CO2 emitted, 600kg were removed by natural sinks. Currently only 550kg are removed per tonne and that amount is falling. Canadell et al. 2007, PNAS

Land Ocean The Efficiency of Natural Sinks: Land and Ocean Fractions In this analysis we don’t detect a trend in the fraction of carbon being removed by the land sink; this doesn’t exclude the possibility that there is a trend given the large inter-annual variability of the land sink, and the fact that the land sink is not calculated directly but obtained as a residual quantity from closing the carbon budget. The fraction going into the ocean sink has clearly declined over the last 50 years. Canadell et al. 2007, PNAS

Causes of the Declined in the Efficiency of the Ocean Sink Part of the decline is attributed to up to a 30% decrease in the efficiency of the Southern Ocean sink over the last 20 years. This sink removes annually 0.7 Pg of anthropogenic carbon. The decline is attributed to the strengthening of the winds around Antarctica which enhances ventilation of natural carbon-rich deep waters. The strengthening of the winds is attributed to global warming and the ozone hole. Credit: N.Metzl, August 2000, oceanographic cruise OISO-5 Le Quéré et al. 2007, Science

[Normalized Difference Vegetation Index] Drought Effects on the Mid-Latitude Carbon Sinks A number of major droughts in mid-latitudes have contributed to the weakening of the growth rate of terrestrial carbon sinks in these regions. Summer 1982-1991 Summer 1994-2002/04 NDVI Anomaly 1982-2004 [Normalized Difference Vegetation Index] Angert et al. 2005, PNAS; Buermann et al. 2007, PNAS; Ciais et al. 2005, Science

Attribution of the recent acceleration of atmospheric CO2 4. Attribution of the recent acceleration of atmospheric CO2

65% - Increased activity of the global economy Attribution of Recent Acceleration of Atmospheric CO2 1970 – 1979: 1.3 ppm y-1 1980 – 1989: 1.6 ppm y1 1990 – 1999: 1.5 ppm y-1 To: Economic growth Carbon intensity Efficiency of natural sinks 2000 - 2006: 1.9 ppm y-1 65% - Increased activity of the global economy 17% - Deterioration of the carbon intensity of the global economy 18% - Decreased efficiency of natural sinks Canadell et al. 2007, PNAS

Conclusions and implications for climate change 5. Conclusions and implications for climate change

Conclusions (i) Since 2000: The growth of carbon emissions from fossil fuels has tripled compared to the 1990s and is exceeding the predictions of the highest IPCC emission scenarios. Atmospheric CO2 has grown at 1.9 ppm per year (compared to about 1.5 ppm during the previous 30 years) The carbon intensity of the world’s economy has stopped decreasing (after 100 years of doing so).

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

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