"The most climate-stressed regions all contained permafrost, which is vulnerable to thaw as temperatures rise," researcher Sue Natali said.

A coronal mass ejection earlier this week may pull the northern lights to more northern U.S. states, forecasters said.

Mount Churchill stands in a white corner of the Alaska map, deceptive in its cold, windblown silence. At least twice in the last few thousand years, the peak’s ice-covered caldera has spewed ash that ...