Collaborative Research: Testing Hypotheses About Fire Using Data Syntheses and Fire Modeling

This research project will investigate how changes in environmental and human activities have influenced fires over time, using a combination of datasets that describe past and present variations in fire. The project also will develop a global fire model to help test hypotheses about the roles that environmental factors and humans have played in controlling the location, size, and frequency of fires at regional-to-global scales. The project will provide new information and insights about relationships among fire, climate and other environmental factors, and human activities. The project will contribute to broader scientific advances in knowledge regarding Earth system processes, and the project will enhance the quality of Earth system models that now are incorporating fire in simulations of the global environment. Knowledge of the ways that human activity, climate, and other environmental factors have affected fires in the past at both regional and global scales is critical to understanding how fires will behave in the future. Given the threats that fires pose for humans and the critical role that fires play in the functioning of many ecosystems, increased awareness of the dynamics of fire behavior has considerable practical utility. Project findings will facilitate enable improved representations of the processes that control fire in models across a variety of climate and land-use conditions, thereby informing decisions about natural resource and fire management efforts. The project will provide education and training opportunities for graduate students, and it will assist in the development of curricular materials dealing with the interactions among fire, natural systems, and human activities for use in elementary and secondary schools.

This project will use satellite-based reconstructions of fire activity to validate modern-day simulations, and it will advance collection of data to study the factors that have influenced the dynamics and impact of fire in the past. The investigators will combine information from a still-expanding global database of fire over the last millennium with the outputs from global fire modeling. Past fire activity will be estimated from charcoal particles in lake sediments at a given depth as well as the time when the charcoal was deposited as determined through the use of radiocarbon dating. The charcoal records will be used to reconstruct past levels of fire activity under a range of climate and land-use conditions, and the reconstructions will be compared with various simulations of past global fire activity. Combining past and present datasets with model simulations of past climate will provide a more rigorous basis for understanding the specific processes that produce reconstructed and observed changes in fire activity than modern-day (satellite) datasets alone.