1. 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

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

3. Recent global carbon trends1.
Recent global carbon trends

4. Anthropogenic C Emissions: Land Use Change
Tropical deforestation
13 Million hectares each year
Borneo, Courtesy: Viktor Boehm
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

5. Anthropogenic C Emissions: Land Use Change
Carbon Emissions from Tropical Deforestation
SUM
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Houghton, unpublished

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

7. Trajectory of Global Fossil Fuel Emissions
SRES (2000) growth rates in % y -1 for :
A1B: 2.42
A1FI: 2.71
A1T: 1.63
A2: 2.13
B1: 1.79
B2: 1.61
2006
2005
Observed %
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

8. 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.
Canadell et al. 2007, PNAS

9. 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

10. 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

11. 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
[ ]
Flux
in 2004
Flux
Growth
in 2004
Population
in 2004
Raupach et al. 2007, PNAS

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

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

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Le Quéré, unpublished; Canadell et al. 2007, PNAS

15. Perturbation of Global Carbon Budget (1850-2006)
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

16. Perturbation of Global Carbon Budget (1850-2006)
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

17. Perturbation of Global Carbon Budget (1850-2006)
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

18. Perturbation of Global Carbon Budget (1850-2006)
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

19. Perturbation of Global Carbon Budget (1850-2006)
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

20. 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

21. The declining efficiency of natural sinks3.
The declining efficiency of natural sinks

22. Partition of Anthropogenic Carbon Emissions into Sinks
[ ]
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

23. 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

24. 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)
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

25. 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

26. 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

27. [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
Summer /04
NDVI Anomaly
[Normalized Difference Vegetation Index]
Angert et al. 2005, PNAS; Buermann et al. 2007, PNAS; Ciais et al. 2005, Science

28. Attribution of the recent acceleration of atmospheric CO24.
Attribution of the recent acceleration of atmospheric CO2

29. 65% - Increased activity of the global economy
Attribution of Recent Acceleration of Atmospheric CO2
1970 – 1979: 1.3 ppm y – 1989: 1.6 ppm y1
1990 – 1999: 1.5 ppm y-1
To:
Economic growth
Carbon intensity
Efficiency of natural sinks
: 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

30. Conclusions and implications for climate change5.
Conclusions and implications for climate change

31. 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).

32. 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.

33. References
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Canadell JG, Pataki D, Gifford R, Houghton RA, Lou Y, Raupach MR, Smith P, Steffen W (2007) in Terrestrial Ecosystems in a Changing World, eds Canadell JG, Pataki D, Pitelka L (IGBP Series. Springer-Verlag, Berlin Heidelberg), pp
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