Quantifying the role of fire in the carbon cycle around the globe, and its climate sensitivity in equatorial Asia
Abstract
Over the last two decades satellite observations have revealed the importance of fire in many ecosystems around the world, but only more recently have quantitative analyses of burned area and emissions been available. We present results from our improved Global Fire Emissions Database (GFED) version 3 based on satellite derived burned area and a biogeochemical model. Model results provide an overview of the role of fires in the global carbon cycle over 1996-2008, and, for the first time, we partition total fire emissions into contributions from deforestation, agriculture, savanna, and forest fires. This allowed us to assess the fraction of total fire emissions that contributed to the build-up of atmospheric CO2 over the last decade because only deforestation fire emissions or emissions from regions where fire frequency increases are net emissions. However, global scale modeling approaches cannot easily incorporate all key regional fire processes. We will therefore focus on the Indonesia region where complicated fuel composition and uncertain burned area estimates have so far prevented reliable emissions estimates so far. By combining emissions from our fire database with atmospheric modeling and measured carbon monoxide mixing ratios from the MOPITT sensor we were able to provide constrained emissions and assess the performance of our database in this region. We found that fire emissions were roughly equal to regional fossil fuel emissions but that emissions showed large interannual variability due to the dependence of fires on drought conditions. This drought-fire link was found to be highly non-linear, revealing the vulnerability of the region to climate change if future droughts become more frequent or more intense. One of the factors contributing to the non-linearity was the climate sensitivity of forest loss. Our findings 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.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.B42B..04V
- Keywords:
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- 0365 Troposphere: composition and chemistry;
- 0428 Carbon cycling (4806);
- 0434 Data sets;
- 0466 Modeling;
- 0480 Remote sensing