Climate and Fire Events during the Cretaceous-Paleogene Hothouse Period

Recent increases in carbon emissions have driven global temperatures upward, significantly elevating wildfire risks and posing substantial challenges to ecosystems. The Mid-Cretaceous (110~82Ma) and Early Paleogene (56~47Ma) periods represent two characteristic hothouse periods that serve as crucial geological analogs for understanding potential future extreme climates and their ecological impacts. This study examines the Cretaceous-Paleogene hothouse period by compiling fire event proxies, including black carbon records, to analyze paleofire characteristics and their relationship with hothouse environments. We conduct a comparative analysis of paleofire patterns between these two periods and investigate their underlying controlling factors. Our key findings reveal: (1) Fire events were predominantly concentrated in the mid-latitude regions of the Northern Hemisphere during both hothouse periods, with geological evidence and climate modeling suggesting that pronounced seasonal climate variations in these regions facilitated fire occurrences; (2) The Cretaceous hothouse period experienced more frequent fire events compared to the Paleogene hothouse period; (3) Elevated temperatures and atmospheric oxygen levels during the Cretaceous hothouse period created favorable conditions for fire activity, while changes in vegetation composition and reduced climatic seasonality during the Paleogene hothouse period suppressed fire occurrence. Future research should prioritize the comprehensive analysis of fire proxies, the development of deep-time paleofire databases, and the assimilation of paleoclimate data to advance understanding of the coupled interactions among fire regimes, vegetation dynamics, and hothouse climates. Such efforts will provide critical insights for projecting future wildfire trends and ecological responses under sustained global warming.