"The increase in large wildfires appears to be another part of a chain of reactions to climate warming," said Dan Cayan, a co-author of the paper and director of the climate research division at Scripps Institution of Oceanography.
He said that while part of the increase may be attributed to natural fluctuations, evidence also links it to the effects of human-induced climate warming.
"I see this as one of the first big indicators of climate change impacts in the continental United States," said research team member Thomas Swetnam, director of the Laboratory of Tree-Ring Research at the University of Arizona in Tucson. "We're showing warming and earlier springs tying in with large forest fire frequencies. Lots of people think climate change and the ecological responses are 50 to 100 years away. But it's not 50 to 100 years away - it's happening now in forest ecosystems through fire."
The research was supported by the National Oceanic and Atmospheric Administration, the Forest Service and the California Energy Commission.
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