Wildfires will be more common in a warming world

CALIFORNIA BURNS every year. But amid a record-breaking heatwave, 2020 is the fieriest year yet (see map). As went to press, more than 7,600 fires had burned over 2.5m acres (1m hectares) of land. The season still has months to run.That fits a long-term trend, for California’s wildfires are getting steadily worse. Blazes in the 2010s burned 6.8m acres on average, up from 3.3m acres in the 1990s. The fire season lasts nearly three months longer now than it did in the 1970s. Over the past decade, the state has spent an average of $3.7bn a year fighting fires. Add the cost of rebuilding, treating casualties and restoration, says Headwaters Economics, a think-tank, and that is perhaps a tenth of the total cost. Although smaller than this year’s, the 2018 fire season was particularly destructive. It killed 100 people and burned tens of thousands of buildings.