Global warming has contributed to wildfire intensity, Stanford expert says

PALO ALTO, Calif. - The California wildfires have prompted some people to wonder whether climate change might be playing a role in the high number and extreme intensity of wildfires in recent years
.
The Carr Fire raging west of Redding is quickly becoming one of the 10 most destructive fires in California history.

"It really looks like something from another world. It's very surreal," said Commander Andrew Hanson of the California National Guard.

Cal Fire says firefighters are battling vast quantities of extremely dry vegetation fueling large fires with extreme heat that has created fire tornadoes even veteran firefighters say they've rarely seen.

"We have very clear evidence that the area burned in the Western United States has been increasing, and it's been increasing pretty rapidly. And we know from scientific studies that global warming has contributed to that increasing wildfire area," said Noah Diffenbaugh, a professor with Stanford University's Department of Earth System Science and Senior Fellow at the Woods Institute for the Environment. 

His research team has studied temperature and carbon emissions data around the globe.

"What global warming is doing is putting a thumb on the scale. The reason is primarily through temperature. The hotter the conditions, the more dried out the vegetation gets and that elevates the wildfire risk," said Diffenbaugh.

An examination of Cal Fire's list of the top twenty largest California wildfires shows that fourteen of them have occurred since 2002. That's not including the Carr Fire which is still burning in Shasta and Trinity counties.

Diffenbaugh says the dry hot conditions have also led to a longer fire seasons.

"Cal Fire used to be able to plan for there being a distinct wildfire season and an off season. And now we're seeing wildfires year-round," said Diffenbaugh.