Some of the ground in the Arctic region is typically frozen most of the year round, but there is new evidence some of it may not be freezing at all, not even in the winter.
The new research was reported Wednesday by National Geographic. If confirmed, scientists say, this could be yet another sign of climate change in a sensitive environment, and the thawed earth could have other troubling consequences.
Father and son scientists Sergey and Nikita Zimov found surprising slushy and muddy turf near the far eastern Russian town of Cherskiy, 200 miles north of the Arctic Circle, when the ground should have been frozen.
The top few layers of earth in the Arctic freeze in the winter and thaw out in the spring. But at a certain depth, the earth remains frozen solid year-round. This is aptly named "permafrost." Some permafrost has been frozen for up to hundreds of thousands of years.
But the Zimovs' research suggests the winter re-freeze in 2017-2018 did not penetrate all the way to the permanently frozen ground beneath, leaving an intermediate layer of thawed ground sandwiched between the surface and the permafrost.