Biomass burning increase in Southeast Asia is dominated by char black carbon
Tom Goreau
- Article
- Open access
- Published: 28 March 2026
Biomass burning increase in Southeast Asia is dominated by char black carbon
- Wenhuai Song,
- Ying Zhang,
- Meng Gao,
- Feng Xie,
- Fang Cao,
- Martin Rauber,
- Sawaeng Kawichai,
- Tippawan Prapamontol,
- Sönke Szidat,
- Yiran Peng,
- Gregory R. Carmichael &
- Yan-Lin Zhang
Communications Earth & Environment , Article number: (2026) Cite this article
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Abstract
Biomass burning emits black carbon, a climate-active aerosol, with poorly constrained climate effects—models capture only 30% of observed black carbon in Southeast Asia. Here we use thermal-optical analysis and radiocarbon source attribution to separate black carbon into char and soot. We find model underestimation arises from missing char-rich emissions, which drive over 90% of regional biomass burning-related black carbon increases. Char has lower mass absorption efficiency than soot, yet most models assign soot-like optical properties to all black carbon. Constraining simulations revises regional direct radiative forcing from 1.95 W m−2 (baseline) to 4.51 W m−2 (mass correction) and 3.71 W m−2 (mass and optical correction). Global analysis reveals nonlinearity: rising biomass burning boosts black carbon loading but reduces its absorption efficiency via char dominance, partially offsetting radiative forcing. This underscores the need to represent black carbon subtypes and their optical properties for accurate climate impact assessments.