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

The Amazon and the modern carbon cycle

Jean Ometto Jean Ometto (1)(1), Antonio Nobre, Antonio Nobre(2)(2) , , Humberto RochaHumberto Rocha(3)(3) , Paulo Artaxo , Paulo Artaxo(4)(4), ,

Luiz MartinelliLuiz Martinelli(1)(1)

(1)(1)CENA/USP, CENA/USP, (2)(2)INPE/INPA, INPE/INPA, (3)(3)IAG/USP, IAG/USP, (4)(4)IF/USPIF/USP

Acknowledgments: The ICDC7 Scientific Committee and the ICDC7 supporting agencies.

atmospheric change

= fossil fuel emissions

land-use change

ocean uptake

land-atm flux terrestrial sink

3.2 = +6.3 +1.6 to

+3.0

-2.1 -1.0 -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

Ecosystem Area

(106) km2

NPP (PgC/yr)

Plant C

(Pg)

Soil C

(Pg)

Tropical for. 17.5 20.1 340 692Temper. for. 10.4 7.4 139 262Boreal for. 13.7 2.4 57 150Artic tundra 5.6 0.5 2 144Med.shrub. 2.8 1.3 17 124Crops 13.5 3.8 4 248Trop.savan. 27.6 13.7 79 345Temp.savan 15.0 5.1 6 172Deserts 27.7 3.2 10 208

Sabine et al. (2004) – SCOPE 62

Amazon alone:21% of tropical forest4% of the area of Earth~6 PgC/yr NPP11% of plant C of world70 Pg of C in plant(Houghton et al. 2001)

0

10

20

30

40

50

60

100 150 200 250 300 350 400 More

AGLB (ton/ha)

Fre

qu

en

cy

0%

20%

40%

60%

80%

100%

120%

Cu

mu

lative p

erc

en

tag

e

Houghton et al. (2001):44 sites - 269±86 ton/ha

•Baker et al. (2003)59 sitest0 = 282±57 ton/hat7 = 294±55 ton/ha

•Overall AGB average: 283±66 ton/ha

Total biomassHoughton et al. (2001):AGB + 30% (roots and dead AGB): 370 ton/ha

Above ground biomass

PantanalReserva Jaru

Fazenda NS Aparecida

Manaus-K34 Flona-Santarem

Brasilia-Cerrado

LBA Flux TowersLBA Flux Towers

Caxiuana

-6-5-4

-3-2-10

12

NE

E (

ton

C/h

a.yr

)

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

COCO22 boundary layer budget boundary layer budget

Inte

grat

eded

dyco

varia

nce

flux

(mol

m)

-2

Integrated boundary layer budget flux (mol C m )-2

SOURCE

SINK

-0.1 -0.2 -0.3 -0.40.3 0.2 0.1

0.1

0.2

0.3

-0.1

-0.2

-0.3

0.4

-0.4

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

The role of tropical rivers in the global Carbon budget

Richey et al (2002)

15

0

5

10

20

25

J F M A M J J A S O N D

Flo

od

ed A

rea

(x 1

04 k

m2)

T (>100m)

MC

S (<100 m) MF

10

15

20

25

%

1.77 x 106 km2

Inundation

: 1.2 ± 0.3 Mg C ha-1 y-1 (basin ~ 0.5 Pg/y)

15

0

5

10

20

25

30

J F M A M J J A S O N D

CO

2 E

vasi

on

(T

g C

mo

-1)

MC

Integrating field pCO2 measurements and flooded areas

13 x Fluvial TOC export = 0.036 Pg C /y

Richey et al (2002)

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 km2)

Methane Emission 22 Tg C y-1

Central Amazon Basin(1.77 million km2)

Methane Emission 6.8 + 1.3 Tg C y-1

Low

Mid

High

atmospheric change

= fossil fuel emissions

land-use change

ocean uptake

land-atm flux terrestrial sink

3.2 = +6.3 +1.6 to

+3.0

-2.1 -1.0 -4.8 to -1.6

Global Carbon Budget, PgC/yr – IPCC 2001

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 +0.26Tropical 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.

Method FAO data Satellite Inversion

Tropical America 24-35% 42-60%Total Tropics 8-12% 20-29% 15-22%

0

5000

10000

15000

20000

25000

30000

35000

Def

ores

tatio

n (k

m2/y

)

* decadal annual mean INPE, 2005

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

1999 2000 2001 2002 2003 2004

Fire Spots in Amazônia1999 - 2004 (NOAA-12)

Amazonia Deforestation1977- 2004 ( km² /y )

Deforestation and fire spots in Amazonia

Deforestation in Amazon BasinDeforestation in Amazon Basin

Source: Daniel Nepstad / IPAM

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;

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

Davidson and Artaxo, 2004

Estimates of net exchange of CO2, CH4 and N2O from the Amazon Basin to the atmosphere

In terms of GWP, the combined impacts of sources and sinks in Amazonia is close to zero