Observations of Growth Rate of Carbon Reservoirs. Keeling et al. (2000) & Marland et al. (2000)

Transcription

1 Carbon Science A new synthesis of the present carbon budget. Building an earth system model for century time scale scenarios An examination of the long term consequences of continued fossil fuel use Scouts

2 Observations of Growth Rate of Carbon Reservoirs Keeling et al. (2000) & Marland et al. (2000)

3 Carbon Sources and Sinks (Pg C yr -1 ) a 1980's 1990 s Fossil Fuel Emissions +5.4 ± ± 0.4 Atmospheric Increase 3.3 ± ± 0.1 NET Oceans & Land 2.1 ± ± 0.4 a Based on IPCC (Prentice et al., 2001) What are the sizes, causes, and expected future behavior of the land and ocean carbon sinks?

4 O 2 /N 2 and CO 2 allow us to separate the land and ocean carbon sinks Measurements by Bender at Cape Grim, Tasmania (1992 to present)

5 Carbon Sources and Sinks (Pg C yr -1 ) a 1980's 1990 s Fossil Fuel Emissions +5.4 ± ± 0.4 Atmospheric Increase 3.3 ± ± 0.1 NET Oceans & Land 2.1 ± ± 0.4 a Based on IPCC (Prentice et al., 2001) Land & Ocean Breakdown Using Oxygen and Carbon Dioxide Observations b Ocean Sink -1.8 ± ± 0.5 Net Land Sink -0.3 ± ± 0.7 b Corrected for ocean warming (Keeling & Garcia, 2002; Plattner et al., 2002; Bopp et al., 2002) Ocean uptake confirmed by ocean inverse (Gloor Gruber, & Sarmiento, 2003), new analysis of oceanic CFC observations (McNeil et al., 2003), & ocean models (Princeton + many others).

6 Ocean uptake is due to chemical dissolution. The ocean has the capacity to dissolve 85% of the present atmospheric anthropogenic CO 2, but because of slow circulation, it presently contains only 37% of the combined atmosphere-ocean inventory Gruber & Sarmiento (2002)

7 The net land sink includes deforestation. Subtracting this gives the size of the total land sink, as shown below: Land & Ocean Breakdown Using Oxygen and Carbon Dioxide Observations b Ocean Sink -1.8 ± ± 0.5 Net Land Sink -0.3 ± ± 0.7 b Corrected for ocean warming (Keeling & Garcia, 2002; Plattner et al., 2002; Bopp et al., 2002). Land Breakdown Tropical deforestation c 0.6 (0.3 to 0.8) Total Land Sink -0.9 (-0.6 to 1.1 ± 0.7) c DeFries et al. (2002) 0.9 (0.5 to 1.4) -1.8 (-1.4 to 2.3 ± 0.7)

8 Land sink mechanism: Northern hemisphere forest uptake = 0.7 Pg C y 1 Adding reservoirs and rivers, agricultural soils, fire suppression in non-forest gives ~ 1 to 1.5 Pg C y -1 (Goodale et. al., 2002; cf. Pacala et al., 2001 on North America)

9 Forest uptake does not appear to be due to CO 2 fertilization, but rather to regrowth in abandoned farmland and previously logged areas as well as to fire suppression (at least in the U.S.) Schlesinger & Lichter (2001); cf. Caspersen et al. (2000) & Pacala et al. (2001)

10 Carbon Science A new synthesis of the present carbon budget. Building an earth system model for century time scale scenarios An examination of the long term consequences of continued fossil fuel use Scouts

11 Net Primary Production predicted by new Princeton land and ocean carbon models (kg C m -2 y -1 ) Upper is observations, lower is model (mmol C m -2 d -1 )

12 Simulation of El Niño by new GFDL Climate Model QuickTime and a Animation decompressor are needed to see this picture.

13 Future scenarios by two Earth System models with CO 2 fertilization Note: The IPSL Earth System model land biosphere is <0.5x as sensitive to warming, and oceanic uptake is 1.8x as strong as Hadley Friedlingstein et al. (in press); Sarmiento & Gruber (2002)

14 Prediction of future North American carbon sink if due to forest regrowth & fire suppression rather than CO 2 fertilization (Pg C y -1 ; Hurtt et al., 2002) 1.5 Flux of Carbon (Pg C/y) Fire suppression ends Fire suppression continues Year

15 Carbon Science A new synthesis of the present carbon budget. Building an earth system model for century time scale scenarios An examination of the long term consequences of continued fossil fuel use Scouts

16 Logistic fossil fuel emissions function for emissions of 5600 Pg C (Note: resource base = 3700 Pg C) Blue is IS92a scenario, which goes to Year Mignone, Greenblatt, & Sarmiento (in preparation)

17 Predicted with a simplified carbon cycle model being developed for integrated assessment Atmospheric pco x pre-industrial x pre-industrial (2.8x pre-industrial w/ sediments) Year

18 Surface Air Warming ( F) 2xCO 2 Climate 4xCO 2 Climate GFDL Model (Manabe & Stouffer)

19 Surface ph Surface ph and carbonate ion response (w/o sediments) Year Fractional change in Surface Hydrogen I Concentration Fractional change in Surface Carbonate I Concentration Year Year

20 Abatement vs. Sequestration Sequestering CO 2 reduces peak but leads to same endpoint Reducing total emissions reduces peak and endpoint Ocean } sediments will reduce endpoint over many 1000s of years

21 Scouts Glacial cycles and atmospheric CO 2 (Sigman) Impact of past climate change on human society (Sigman) Detecting warming with Ar/N 2 measurements in atmosphere (Bender) Deep ocean injection (Sarmiento group) Ocean fertilization (Sarmiento group) Impacts of wind power on climate (Pacala group) Impacts of biological renewables on climate, hydrology & air quality (Pacala group)

22 Oceanic Direct Injection for 100 years Injection sites: New York Bay of Biscay San Francisco Tokyo Bombay Jakarta Rio de Janeiro Atmospheric CO 2 : S650 - increases to 650 ppm by ~2150 OCMIP study

23 Development of improved ocean circulation models Red = models Blue = observations Matsumoto et al. (in preparation)

24 New scenario: patch scale (4 square) fertilization for one month 1. Efficiency of fertilization is 2 to 12% if iron alone is added, about 40% if iron and nutrients are added. 2. Takes up ~0.001 to 0.1 Gt C per episode. 3. Verification is impractical. 4. Economic impacts on fisheries could exceed value of carbon sequestration.

25 Climate Change and the Collapse of the Mayan Civilization Haug et al. (2001) The figure shows that the Intertropical Convergence Zone changes with season in both the Mayan Lowlands and Cariaco Basin.

26 Titanium in Cariaco Basin Sediments Low rainfall XRF measurements of titanium provide an annual record of rainfall! High rainfall The fall of the Classical Maya civilization occurred during a period of increased dryness exacerbated by extreme events.

27 Carbon Science - Future Continue to improve our understanding of the ongoing carbon sinks. Complete basic earth system model development and begin scenario studies. Add new components to earth system model (e.g., functional biodiversity) Contribute to development of integrative products in next phase of CMI Scouts