I helicoptered into the Alaskan wilderness with scientists on the frontlines of permafrost research. Andrew Haverdink, a tall grad student in a rain bib and rubber boots, wrenched a double-handed drill from the frozen soil beneath much of Alaska's Denali National Park. A solid, cylindrical core of ancient soil emerged, dark and rich permafrost at least a foot long. He was among a team of Northern Arizona University students and staff gathering samples and data from a research plot marked with surveyor's tape across tussocks, alders, and fireweed.
In late June 2013, a lightning strike sparked a fire in this stretch of mostly treeless tundra. Whipped by Chinook winds, the fire ripped across nearly 35,000 acres. It burned deep into the topsoil, stripping away the insulating layer that preserves the frozen permafrost, a massive storehouse of carbon underlying 85% of Alaska. A 2016 survey found that where the fire burned hottest, the thawed active layer extended between a foot and nearly two feet deeper than in plots outside the burn scar.
Crucially, the fire crossed survey grids the National Park Service had established in 2001. That pre-fire snapshot gave the team a rare chance to study how the blaze has altered vegetation, carbon, and permafrost over time, says Xanthe Walker, one of the project's principal investigators. Direct observations from high-latitude fires are helping scientists understand how wildfire and permafrost loss feed into climate change. "There's a lot of uncertainty," Walker says. "These are huge biomes with massive fires that no one's ever been to or ever looked at."
Researchers are working to untangle these cascading feedbacks. As warming fuels more frequent and severe fires, more permafrost thaws, releasing greenhouse gases that threaten to drive further warming. Permafrost covers 15% of the Northern Hemisphere's land surface and holds about 1.5 trillion tons of carbon, roughly twice the amount in the atmosphere.
Source: MIT Technology Review · Summarized by HeadlinesBriefing