Asian inland wildfires driven by glacial-interglacial climate change

Significance We reconstructed a unique record of soot variations from a classic Chinese loess section that reflects regional-to-continental scale high-intensity fires in central Asia over the entire Quaternary. This study shows cyclicity of wildfire over glacial–interglacial intervals. High-intensity wildfires were more common and dust loads were high during dry and cold glacial periods, implying a synchronous response to climate change. Our study suggests potential linkages among wildfire, mineral dust, marine biogeochemical cycles, atmospheric CO2, and glacial–interglacial climate change. Understanding these connections among earth systems provides insights into climate dynamics during the geological past and may improve predictions for the future.
Wildfire can influence climate directly and indirectly, but little is known about the relationships between wildfire and climate during the Quaternary, especially how wildfire patterns varied over glacial–interglacial cycles. Here, we present a high-resolution soot record from the Chinese Loess Plateau; this is a record of large-scale, high-intensity fires over the past 2.6 My. We observed a unique and distinct glacial–interglacial cyclicity of soot over the entire Quaternary Period synchronous with marine δ18O and dust records, which suggests that ice-volume-modulated aridity controlled wildfire occurrences, soot production, and dust fluxes in central Asia. The high-intensity fires were also found to be anticorrelated with global atmospheric CO2 records over the past eight glacial–interglacial cycles, implying a possible connection between the fires, dust, and climate mediated through the iron cycle. The significance of this hypothetical connection remains to be determined, but the relationships revealed in this study hint at the potential importance of wildfire for the global climate system.