Wildfire activity has been unusually extreme in many parts of the world in recent years. These broadscale changes in fire regimes pose a significant threat to human health, ecosystems, and the global climate system. It is difficult to understand how and why these changes are occurring without long-term, global fire-history data. Satellite images, historical records, and dendrochronological data have been used to create short histories of up to 100 years in duration, but no spatially explicit syntheses exist for longer time periods. This doctoral dissertation research project will compile and synthesize published charcoal data to reconstruct global fire activity since the last glacial maximum. The doctoral candidate will examine changes in biomass burning during periods of both gradual and abrupt climate change and compare paleofire and pollen data to investigate long-term fire, vegetation, and climate dynamics. More specifically, she will create a global database of charcoal-based paleofire records that spans the last 21,000 years; perform a meta-analysis of the highest-resolution paleofire records, which are concentrated in North America; integrate charcoal and pollen data from North America to examine fire and fuel relationships under changing climate conditions; and use observed and simulated paleofire data to make a global data-model comparison of fire activity at the time of the last glacial maximum and during the mid-Holocene.
Results from this study will enhance basic understanding of the spatial and temporal patterns of fire activity and of the mechanisms behind major shifts in fire regimes that have occurred since the last glacial maximum. The detailed analysis of high-resolution charcoal data and pollen data will provide new insights into specific dimensions of fire-regime changes, such as how fire frequency versus fire severity have varied across climate and vegetation gradients. The data-model comparisons will validate a coupled vegetation-fire model and provide a new tool for testing hypotheses about interactions between fire, climate, vegetation and human activities. Data will be shared with the International Multiproxy Paleofire Database sponsored by the World Data Center for Paleoclimatology at NOAA. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.
