1. Seventh Carbon Dioxide Conference – Boulder, September 25-30, 2005 The Amazon and the modern carbon cycle Jean Ometto (1), Antonio Nobre (2), Humberto Rocha (3), Paulo Artaxo (4), Luiz Martinelli (1) (1) CENA/USP, (2) INPE/INPA, (3) IAG/USP, (4) IF/USP Acknowledgments: The ICDC7 Scientific Committee and the ICDC7 supporting agencies.

2. atmospheric change = fossil fuel emissions land-use change ocean uptake land-atm fluxterrestrial sink 3.2=+6.3+1.6 to +3.0 -2.1-4.8 to -1.6 Global Carbon Budget, PgC/yr – IPCC 2001 Nearly 20 years (1982-1999) of satellite observations of Earth’s vegetation reveal increase of the overall productivity of land plants by 6 % Nemani (2003) ***Data to be revised after this meeting

3. EcosystemArea (10 6 ) km 2 NPP (PgC/yr) Plant C (Pg) Soil C (Pg) Tropical for. 17.520.1340692 Temper. for. 10.47.4139262 Boreal for. 13.72.457150 Artic tundra 5.60.52144 Med.shrub. 2.81.317124 Crops 13.53.84248 Trop.savan. 27.613.779345 Temp.sava n 15.05.16172 Deserts 27.73.210208 Sabine et al. (2004) – SCOPE 62 Amazon alone: 21% of tropical forest 4% of the area of Earth ~6 PgC/yr NPP 11% of plant C of world 70 Pg of C in plant (Houghton et al. 2001)

4. Houghton et al. (2001): 44 sites - 269±86 ton/ha Baker et al. (2003) 59 sites t0 = 282±57 ton/ha t7 = 294±55 ton/ha Overall AGB average: 283±66 ton/ha Total biomass Houghton et al. (2001): AGB + 30% (roots and dead AGB): 370 ton/ha Above ground biomass

5. Pantanal Reserva Jaru Fazenda NS Aparecida Manaus-K34Flona-Santarem Brasilia-Cerrado LBA Flux Towers Caxiuana

6. Estimates of net ecosystem exchange (NEE) obtained by eddy covariance technique and by aboveground biomass estimates. Biomass inventory (Backer et al, 2004), eastern and central plots, western plots and floodplain plots, respectively

7. CO 2 boundary layer budget A comparison of estimates of the Amazonian forest carbon budget as obtained by CBL budgeting and the eddy covariance methods for Manaus in July 2001. Square symbols represent night time periods and circles represent daytime the daytime period. (Jon Lloyd et al) Night fluxes are higher in budget study

8. The role of tropical rivers in the global Carbon budget Richey et al (2002)

9. 15 0 5 10 20 25 JFMAMJJASON D Flooded Area (x 10 4 km 2 ) T (>100m) MC S (<100 m)MF 10 15 20 25 % 1.77 x 10 6 km 2 Inundation  : 1.2 ± 0.3 Mg C ha -1 y -1 (basin ~ 0.5 Pg/y) 15 0 5 10 20 25 30 JFMAMJJASON D CO 2 Evasion (Tg C mo -1 ) MC Integrating field pCO 2 measurements and flooded areas 13 x Fluvial TOC export = 0.036 Pg C /y Richey et al (2002)

10. Methane emissions from wetlands Final estimates suggest that the Amazon Basin wetlands may produce as much as 20% of the natural global source of methane. (Melack et al., 2004) Mainstem Emissions Interannual Variability Lowland Amazon Basin (<500 m asl) (5.19 million km 2 ) Methane Emission 22 Tg C y -1 Central Amazon Basin (1.77 million km 2 ) Methane Emission 6.8 + 1.3 Tg C y -1 Low Mid High

11. atmospheric change = fossil fuel emissions land-use change ocean uptake land-atm fluxterrestrial sink 3.2=+6.3+1.6 to +3.0 -2.1-4.8 to -1.6 Global Carbon Budget, PgC/yr – IPCC 2001

12. Houghton et al. (2000) Fearnside (2001) Houghton et al. (2003) DeFries et al. (2002) Archard et al. (2003) Gurney et al. (2002) Amazon +0.18+0.26 Tropical America +0.75+0.43 Total Tropics +2.20+0.91+0.96+1.20 Flux of carbon (PgC/yr) due to land use changes in the tropics estimated by different methods and authors.  The combined effects of clear-cutting, forest regrowth on abandoned land, and logging in the 1990’s may have released equivalent to 10 to 25% of global, human-induced emissions. MethodFAO dataSatelliteInversion Tropical America 24-35%42-60% Total Tropics 8-12%20-29%15-22%

13. Fire Spots in Amazônia 1999 - 2004 (NOAA-12) Amazonia Deforestation 1977- 2004 ( km² /y ) Deforestation and fire spots in Amazonia

15. Deforestation in Amazon Basin Source: Daniel Nepstad / IPAM

16. Some aspects related to LUC Agricultural “Frontier”; In several regions development is associated to expansion; Socio-Economic drivers: –Pressure from large scale agricultural crops ~ soy bean, sugar cane and others –Pastures, logging –Road construction Pressure from increase of population;

17. Critical aspects to reduce uncertainties in carbon balance estimates for the Amazon Region  Flux measurements Eddy Covariance ABL/FT  Modeling  Biomass Measurements Deforestation Radon River/Floodplains Flux/Concentration

18. Davidson and Artaxo, 2004 Estimates of net exchange of CO 2, CH 4 and N 2 O from the Amazon Basin to the atmosphere In terms of GWP, the combined impacts of sources and sinks in Amazonia is close to zero