Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, USA.
Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland.
Nat Commun. 2021 Jan 11;12(1):212. doi: 10.1038/s41467-020-20570-w.
Attribution studies have identified a robust anthropogenic fingerprint in increased 21 century wildfire risk. However, the risks associated with individual aspects of anthropogenic aerosol and greenhouse gases (GHG) emissions, biomass burning and land use/land cover change remain unknown. Here, we use new climate model large ensembles isolating these influences to show that GHG-driven increases in extreme fire weather conditions have been balanced by aerosol-driven cooling throughout the 20th century. This compensation is projected to disappear due to future reductions in aerosol emissions, causing unprecedented increases in extreme fire weather risk in the 21st century as GHGs continue to rise. Changes to temperature and relative humidity drive the largest shifts in extreme fire weather conditions; this is particularly apparent over the Amazon, where GHGs cause a seven-fold increase by 2080. Our results allow increased understanding of the interacting roles of anthropogenic stressors in altering the regional expression of future wildfire risk.
归因研究已经确定，在 21 世纪，人为因素导致野火风险增加的现象明显。然而，与人为气溶胶和温室气体（GHG）排放、生物质燃烧以及土地利用/土地覆盖变化等各个方面相关的风险仍不清楚。在这里，我们利用新的气候模型大集合来隔离这些影响，结果表明，在整个 20 世纪，气溶胶驱动的冷却效应抵消了 GHG 导致的极端火灾天气条件的增加。由于未来气溶胶排放量的减少，预计这种补偿将会消失，这将导致 21 世纪 GHG 持续上升时，极端火灾天气风险将以前所未有的速度增加。温度和相对湿度的变化导致极端火灾天气条件发生最大变化；在亚马逊地区，这种情况尤为明显，到 2080 年，GHG 将导致火灾风险增加七倍。我们的研究结果提高了对人为压力因素在改变未来野火风险的区域表现方面相互作用的认识。
