How to study a swiftly melting climate disaster

Andrew Haverdink, a tall grad student in a rain bib and rubber boots, wrenched a double-handed drill from the frozen soil that underlies much of Alaska’s Denali National Park and then unclipped the hollow barrel from the end of the bit.

He knelt in front of a blue tarp, lined the barrel up with a plastic tray, and pushed a rod through the opposite end. A perfect solid, cylindrical core of ancient soil emerged—dark, rich permafrost at least a foot long.

On that late morning in early July, Haverdink was among a team of Northern Arizona University students and staff gathering samples and data from a research plot, divided by surveyor’s tape unspooled atop tussocks, alders, and fireweed.

In late June of 2013, a lightning strike sparked a fire in this stretch of mostly treeless tundra, in the northern backcountry of the park. …