High-resolution analysis of soot deposition over the past 2.6 million years reveals a link between glacial cycles and inland Asian high-intensity wildfires, according to a study. With the occurrence and passing of ice ages during the Quaternary period, mountain glaciers on the central Asian plateau have grown and shrunk with climate oscillations. To determine how dry glacial periods and wet interglacial periods affected wildfire events, Yongming Han, Zhisheng An, Junji Cao, and colleagues reconstructed a wildfire record for the central Asian plateau by measuring soot and char particles in more than 1,300 wind-blown silt sediment samples. The authors measured black carbon in the loess sediment and distinguished soot, which is composed of submicron-sized particles produced under fast-burning, high-intensity conditions, from char, which contains larger particles produced by low-intensity, smoldering combustion. The results revealed that high-intensity fires were cyclical and associated with dry glacial periods when dust loads in the atmosphere were high. The periods of high-intensity fire events also correlated with decreased atmospheric carbon dioxide. According to the authors, the results hint at possible links between fires, dust, and climate through the iron cycle and suggest potential effects of wildfire on the global climate system.
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Article #18-22035: "Asian inland wildfires driven by glacial-interglacial climate change," by Yongming Han et al.
MEDIA CONTACT: Yongming Han, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, CHINA; e-mail: yongming@ieecas.cn
Proceedings of the National Academy of Sciences