Climate regulation of fire emissions and deforestation in equatorial Asia

doi:10.1073/pnas.0803375105

Climate regulation of fire emissions and deforestation in equatorial Asia

^aFaculty of Earth and Life Sciences, VU University, 1081HV Amsterdam, The Netherlands;
^bDepartment of Geography, University of Maryland, College Park, MD 20742;
^cIntegrated Earth System Sciences Institute, Cranfield University, Cranfield MK43 0AL, United Kingdom;
^dDepartment of Earth System Science, University of California, Irvine, CA 92697;
^eNicholas School of the Environment, Duke University, Durham NC 27708;
^fScience Systems and Applications, Inc., Lanham, MD 20706;
^gCenter for International Forestry Research, Jl. CIFOR, Situgede, Bogor, 16680, Indonesia;
^hDepartment of Meteorology and Air Quality, Wageningen University and Research Center, 6700AA, Wageningen, The Netherlands;
ⁱNASA Goddard Space Flight Center, Hydrospheric and Biospheric Sciences Laboratory, Greenbelt, MD 20771; and
^jDepartment of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027

Edited by Christopher B. Field, Carnegie Institution of Washington, Stanford, CA, and approved October 27, 2008 (received for review April 8, 2008)

Abstract

Drainage of peatlands and deforestation have led to large-scale fires in equatorial Asia, affecting regional air quality and global concentrations of greenhouse gases. Here we used several sources of satellite data with biogeochemical and atmospheric modeling to better understand and constrain fire emissions from Indonesia, Malaysia, and Papua New Guinea during 2000–2006. We found that average fire emissions from this region [128 ± 51 (1σ) Tg carbon (C) year⁻¹, T = 10¹²] were comparable to fossil fuel emissions. In Borneo, carbon emissions from fires were highly variable, fluxes during the moderate 2006 El Niño more than 30 times greater than those during the 2000 La Niña (and with a 2000–2006 mean of 74 ± 33 Tg C yr⁻¹). Higher rates of forest loss and larger areas of peatland becoming vulnerable to fire in drought years caused a strong nonlinear relation between drought and fire emissions in southern Borneo. Fire emissions from Sumatra showed a positive linear trend, increasing at a rate of 8 Tg C year⁻² (approximately doubling during 2000–2006). These results highlight the importance of including deforestation in future climate agreements. They also imply that land manager responses to expected shifts in tropical precipitation may critically determine the strength of climate–carbon cycle feedbacks during the 21st century.

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Footnotes

¹To whom correspondence should be addressed. E-mail: guido.van.der.werf{at}falw.vu.nl
Author contributions: G.v.d.W., J. Dempewolf, S.N.T., J.T.R., and R.S.D. designed research; G.v.d.W., J. Dempewolf, S.N.T., P.S.K., L.G., D.M., and W.P. performed research; G.v.d.W., J. Dempewolf, S.N.T., D.C.M., G.J.C., and J. Dolman analyzed data; and G.v.d.W., J. Dempewolf, J.T.R., and R.S.D. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0803375105/DCSupplemental.