Wildfire Season Is Scorching the West, made worse by global warming

http://www.climatecentral.org/news/western-wildfire-season-off-to-blazing-start-21661

Andrea Thompson By Andrea Thompson

The West is ablaze as the summer wildfire season has gotten off to an intense start. More than 37,000 fires have burned more than 5.2 million acres nationally since the beginning of the year, with 47 large fires burning across nine states as of Friday.

The relatively early activity is quickly becoming the norm, with rising temperatures making the fire season longer than it used to be. The warming fueled by greenhouse gases is also helping to create more and larger fires as it dries out more vegetation that acts as fuel for fires.

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A 2016 Climate Central analysis showed that the annual number of large fires has tripled since the 1970s and that the amount of land they burn is six times higher than it was four decades ago.

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While multiple factors, including land use and tree disease, influence fire activity, climate change is playing a role in those trends. A study published in October found that rising temperatures accounted for nearly half of the increase in acres burned, as they helped to dry out forests and extend the length of the fire season.

The fire season is 105 days longer than it was in the 1970s, the Climate Central analysis found.

The lengthening of the fire season has become clear in California, which usually didn’t see major fires until the Santa Ana winds kicked in in the fall and vegetation had dried out over several months.

Now bouts of hot, dry weather are coming earlier and earlier, setting the stage for prime fire conditions. Southern California already has a nearly year-round fire season, Scott Stephens, a professor of fire science at the University of California, Berkeley, said.

With those hot periods likely coming earlier and earlier in spring and summer as global temperatures continue to rise, “you’re going to have a longer period where fire can ignite and move,” Stephens said.

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