Seventh Carbon Dioxide Conference – Boulder, September 25-30, 2005

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. Global Carbon Budget, PgC/yr – IPCC 2001 ***Data to be revised after this meeting 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)

3. 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) Sabine et al. (2004) – SCOPE 62

4. Above ground biomass • 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

5. Manaus-K34 Flona-Santarem LBA Flux Towers Fazenda NS Aparecida Caxiuana Pantanal Reserva Jaru Brasilia-Cerrado

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. CO2 boundary layer budget Night fluxes are higher in budget study 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)

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

9. Integrating field pCO2 measurements and flooded areas 3 0 1.77 x 106 km2 2 5 T (>100m) 25 2 5 CO2 Evasion (Tg C mo-1) 2 0 % 20 15 2 0 1 5 10 1 0 Flooded Area (x 104 km2) 1 5 5 MC 1 0 0 J F M A M J J A S O N D 5 S (<100 m) MF 0 D J F M A M J J A S O N MC Inundation Richey et al (2002) : 1.2 ± 0.3 Mg C ha-1 y-1 (basin ~ 0.5 Pg/y) 13 x Fluvial TOC export = 0.036 Pg C /y

10. Methane emissions from wetlands Mainstem Emissions Interannual Variability Central Amazon Basin (1.77 million km2) High Methane Emission 6.8 + 1.3Tg C y-1 Mid Lowland Amazon Basin (<500 m asl) (5.19 million km2) Low Methane Emission 22 Tg C y-1 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)

11. Global Carbon Budget, PgC/yr – IPCC 2001

12. 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.

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

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 Eddy Covariance ABL/FT • Flux measurements Radon Flux/Concentration • Modeling River/Floodplains Measurements • Biomass Deforestation

18. Estimates of net exchange of CO2, CH4 and N2O from the Amazon Basin to the atmosphere Davidson and Artaxo, 2004 In terms of GWP, the combined impacts of sources and sinks in Amazonia is close to zero