Fossil evidence that increased wildfire activity occurs in tandem with periods of global warming in Earth's past

Abstract

It is predicted that under a warming climate, wildfire frequency will likely increase. The increase in fire activity is hypothesized as a likely consequence of increased atmospheric CO2-driven climate warming having the potential to influence fire weather and increase ignition probability.Periods of greenhouse gas-induced global warming have occurred many times in Earth's history, evidenced as episodes of perturbation in climate related proxies within the rock record. Coupled with an extensive record of wildfire in the fossil record dating back ~400 million years, the geological record thus provides an opportunity to aid in our understanding of how past periods of climate change may have altered wildfire activity. This review presents a collation of published records of inferred wildfire activity across some of these episodes of major greenhouse gas-induced warming events in Earth's past, to assess whether a link exists between periods of greenhouse gas-induced climate warming and the increased likelihood of wildfire activity. Within this review, it is concluded that there is substantial evidence of increased combustion products, taken to be indicative of increased wildfire activity, occurring in tandem with periods of global climate changes in Earth's past. These patterns of climate-driven wildfire changes may therefore provide information for our future predictions of wildfire occurrence on a warming planet.