Thanks to charcoal layers in sediments and methane concentrations in ice cores, we have a good record of past wildfire activity. This record shows dramatic fluctuations over time; for example, there was a significant lull between 1600 and 1750, followed by an unprecedented surge beginning around 1800. This was followed by a rapid decline beginning in 1900 that has continued until the present.

Previous models of wildfire activity have struggled to explain these fluctuations, in part because it’s difficult to tease out the effect that humans have had on both igniting and suppressing wildfires. The present model, developed by NASA researchers Olga Pechony and Drew Shindell, is the first to successfully replicate the past 1,000 years of wildfire history. The scientists used data from a number of satellite instruments to validate the model, including information on precipitation, vegetation and lightning and fire activity.

When Pechony and Shindell combined the model with an existing climate model, they were able to simulate future wildfire trends under a range of different climate regimes. The results suggest that there will be large increases in fire activity in India, Australia, central Asia and Siberia, southern Europe and southern Africa. ‘Our projections show that our rising temperatures – this time driven by humans – are on the verge of reasserting control over the world’s fires,’ Pechony said.

December 2010