Earth & Sky

Warming climate sparks wildfires, say scientists

A warming climate has triggered increased wildfire activity in the western U.S.

That’s the conclusion drawn by environmental scientist Anthony Westerling of the University of California, Merced. He co-authored a study that looked at 34 years of government fire data since 1970. Westerling focused on large fires in western forests of over 1,000 acres.

Anthony Westerling: What we saw very clearly was that most of the fires occurred in years with warm springs, sometimes drier winters, and early spring snow melts. And we had a much longer fire season in these years.

An early snow melt can create dry conditions vulnerable to fire. Westerling told Earth & Sky that the first 17 years of the study saw over 200 large fires. In the next 17 years, ending in 2003, there were over 900. Most of the increased wildfire activity was in forests at around 7,000 feet in elevation in the northern Rocky mountains.

Anthony Westerling: These forests are thought to be the least effected, in terms of changes in the risk of a large fire due to a century or more of land management and fire suppression in the western United States. So we saw very clearly a climatic signal in an area where we don’t have other explanations for why the fires have increased so dramatically.

Thanks today to NASA.