fires and the contemporary global carbon cycle

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Fires and the Contemporary Global Carbon Cycle Guido van der Werf (Free University, Amsterdam, Netherlands) In collaboration with: Jim Randerson (UCI, CA, USA) Louis Giglio (SSAI, MD, USA) Prasad Kasibhatla (Duke University, NC, USA) Jim Collatz (NASA GSFC, MD, USA)

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Fires and the Contemporary Global Carbon Cycle Guido van der Werf (Free University, Amsterdam, Netherlands) In collaboration with: Jim Randerson (UCI, CA, USA) Louis Giglio (SSAI, MD, USA) Prasad Kasibhatla (Duke University, NC, USA) Jim Collatz (NASA GSFC, MD, USA). Main Objectives - PowerPoint PPT Presentation

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Page 1: Fires and the Contemporary Global Carbon Cycle

Fires and the Contemporary Global Carbon Cycle

Guido van der Werf (Free University, Amsterdam, Netherlands)

In collaboration with:

Jim Randerson (UCI, CA, USA)

Louis Giglio (SSAI, MD, USA)

Prasad Kasibhatla (Duke University, NC, USA)

Jim Collatz (NASA GSFC, MD, USA)

Page 2: Fires and the Contemporary Global Carbon Cycle

Main Objectives

1. Quantify the contemporary amount of biomass burned on a global scale

2. Assess the role of biomass burning in the global CO2 and CH4 cycle

3. Determine the climate sensitivity of biomass burning

Page 3: Fires and the Contemporary Global Carbon Cycle

‘Classical’ approach: Emissions = Σx,t A × B × CC × EF

Giglio et al, submitted to ACPD

Page 4: Fires and the Contemporary Global Carbon Cycle

Net PrimaryProduction

Allocation=f (treecover)

AbovegroundBiomass C

BelowgroundBiomass C

Combustion

BelowgroundLitter C

AbovegroundLitter C

f(A,CC,M) f(A,CC)

Respiration

Fuelwoodcollection

Herbivoreconsumption

A = area burnt

CC = combustion completeness

M = fire induced mortality

Fires embedded in the CASA satellite-driven biogeochemical model

Page 5: Fires and the Contemporary Global Carbon Cycle

Annual fire emissions, averaged over the 1997 – 2004 period

Page 6: Fires and the Contemporary Global Carbon Cycle

Annual fire emissions as percentage of NPP, averaged over the 1997 – 2004 period

Page 7: Fires and the Contemporary Global Carbon Cycle

Fuel consumption as calculated by CASA

Emission (g) per m2 burned

Page 8: Fires and the Contemporary Global Carbon Cycle

On a global scale, IAV in burned area and emissions are decoupled

BA driven by savannas

Emissions driven by forest fires (including deforestation)

1997 peat burning in Asia

Page 9: Fires and the Contemporary Global Carbon Cycle

Observed CO anomalies

Boreal region CO (forward modeling)

Atmospheric CO as a constrain on fire emissions

Page 10: Fires and the Contemporary Global Carbon Cycle

• CO: forward modeling optimized in inversion to fit observations

• CO2: fires explain ~2/3 of the growth rate anomaly

(60% SE-Asia, 30% C+S America, 10% Boreal)

• CH4: fires explain most of the growth rate anomaly.

Contribution of IAV in fire activity to CO2 and CH4 growth rates

Page 11: Fires and the Contemporary Global Carbon Cycle

Mismatch in seasonality between top-down and bottom-up observations (southern Africa)

Atmosphere: peak in September - October

Satellite surface observations: peak in June – July - August

Page 12: Fires and the Contemporary Global Carbon Cycle

Effect of IAV in precipitation on fire activity

Page 13: Fires and the Contemporary Global Carbon Cycle

Concluding remarks

1. Global (vegetation) fire emissions as calculated by our modeling framework is ~2.5 Pg C / year, largest uncertainties in deforestation regions

2. IAV in fire emissions contributed significantly to variability in the 1997-2001 growth rate of CO2 and CH4.

3. IAV in fire emissions is dominated by IAV in forest fires. Implications:

• IAV in burned area and emissions are decoupled

• IAV in CO and CH4 is larger than IAV in C or CO2

4. (Multi-specie) inversions and high resolution (deforestation) fire modelling ideally employed to further improve estimates