What Megablazes Tell Us About the Fiery Future of Climate Change
This summer, Alaska was set to burn due to an unusually warm winter combined with a pitiful snowfall. (Anchorage recorded barely two feet of snow — shattering a record that had held up for 60 years.) With spring came soaring temperatures: more than seven degrees above average statewide. The city of Eagle, Alaska, 200 miles east of Fairbanks, hit 91 degrees in May — a higher temperature than had been recorded to that date in either Houston or Dallas.
When lightning struck, Alaska blazed. “At one point this summer,” Obama noted, “more than 300 wildfires were burning at once.” Blazing largely out of control, the fires consumed 5.1 million acres — the second-worst fire season on record. As bad as wildfire has been in Alaska, it will only get worse, according to the National Climate Assessment, the 2014 federal report that gauges regional risks of climate change. Assume everything goes right at climate talks this year in Paris; assume world governments leap to action with aggressive measures to curb carbon emissions — even under this scenario, according to the report, Alaska wildfire will double by 2050 and triple by 2100.
As worldwide temperatures rise, wildfires will only increase. But what is less intuitive is how a dangerous drought and fire season have gripped the Pacific Northwest — despite annual precipitation levels that were close to normal. The problem, it turns out, was not a lack of water, but rather that so little of it fell as snow.
Under typical conditions, deep mountain snowpacks and late spring stream runoff give protection from wildfire by keeping trees and vegetation moist far into summers that can run hot and dry — particularly east of the Cascade Mountains. This winter, temperatures soared 5.6 degrees above normal in the region, leading to record-low snowpack, and to stream runoff that peaked, in many places, in the dead of February. In March, Inslee declared a statewide drought emergency in Washington. By June, the snowpack was just . . . gone.
“This drought is unlike any we’ve ever experienced,” Maia Bellon, the director of Washington state’s Department of Ecology, said in May. It has primed the region to burn. Susan Prichard, a fire ecologist at the University of Washington, says the sudden drying of overgrown forests created a “perfect storm” for big fires in eastern Oregon and Washington. “It leads us,” she says, “to a tinderbox situation.”
The warming air is sucking the forests dry — literally. Man-made higher temperatures increase the atmosphere’s appetite for moisture; Williams, the Columbia climate scientist, jokes that the effect is like a Mafia shakedown, with the air constantly demanding more water from the land. In wet years, the atmosphere’s increased thirst doesn’t matter much. But in times of drought, this tax on the water system is significant and damaging. “That cost is now becoming large enough that it’s really detectable,” Williams says, “and it’s reducing water availability for humans and ecosystems.”