A STUDY OF WILDFIRE EVOLUTION DURING THE PALEOCENE-EOCENE WARM PERIOD IN THE NORTHERN HEMISPHERE
The Paleocene is a critical transition period for the formation of modern climate and vegetation,and wildfire activities are intrinsically coupled with climate,vegetation and carbon cycle.The study of wildfire evolution during three typical warm periods in the Paleocene-Eocene(66～34 Ma),including the Paleocene-Eocene Thermal Maximum(PETM,ca.55.9 Ma),the Early Eocene Climate Optimum(EECO,53.3～49.1 Ma),and the Middle Eocene Climate Optimum(MECO,40.5～40.1 Ma),is of great significance to reveal climate and vegetation changes and their impacts.Based on the Paleocene-Eocene wildfire data from the Erlian Basin in the southern Mongolian Plateau,12 other wildfire records from different sites in the Northern Hemisphere during this time period were collected.In terms of the spatial distribution of the study sites,the newly integrated dataset covers the Northern Hemisphere regions of Europe,North America,South Asia and East Asia.Our study reconstructed the characteristics and evolution of wildfire activities in the Northern Hemisphere and explored its driving mechanism from the perspective of long-scale geologic records.The results show that the scale and intensity of wildfires during the warm periods of the Paleocene-Eocene varied,and that wildfires during the extreme warm period of the PETM were more intense than those during the warm periods of the EECO and MECO,but not very significant.The Paleocene-Eocene warm period was not characterized by sustained and large-scale wildfires,and the"low wildfire state"generally does not support the"wildfire hypothesis",which emphasizes the influence of burning activities on the global carbon cycle.The"Paleocene low-wildfire puzzle"has been initially explored through the discussion of the relationship between wildfire occurrence and environmental factors such as temperature,precipitation,vegetation,and CO2 concentration.Our study suggests that the indistinct seasonality of the Paleocene-Eocene climate resulted in short dry seasons,which was not conducive to the formation of combustible"fuels"and potential ignition source,and that this is likely the main cause of the"low wildfire"in the Early Cenozoic.
万方数据
维普
