This environmental news involves something distant, obscure and important. It's known as permafrost, which is permanently frozen ground. Most permafrost has been solid ice for thousands and thousands of years. It draws attention now because new research shows some of Alaska's permafrost is thawing. U.S. scientists say the Yukon Delta National Wildlife Refuge, 350 miles south of the Arctic Circle, could lose much of its permafrost by 2050. That would mean "all kinds of consequences both locally for this region, for the animals and the people who live here, as well as globally," says Max Holmes, deputy director of the Woods Hole Research Center, which has measured the thawing.

Specialists pay attention because vast amounts of carbon are part of organic matter in the frozen ground. It exists in plants that took carbon dioxide from the atmosphere centuries ago, died and froze before they could decompose. Worldwide, permafrost is thought to contain about twice as much carbon as is currently in the atmosphere. Once this ancient organic material thaws, microbes convert some of it to carbon dioxide and methane -- which flow into the atmosphere and cause even more warming. Think of it like food in your freezer: If the freezer breaks down, it’s not long until the contents start rotting.

Research this past summer at a temporary field station in the remote Alaskan refuge is aimed at exploring how thawing permafrost affects the landscape and how much and what mix of greenhouse gases is released. In addition to that atmospheric issue, there's also a ground-level impact. Permafrost is an ideal surface to build on – as long as it stays frozen. But when that solid base thaws, buildings sinking into the ground and roads become wavy. There's even a phenomenon called drunken forests – trees tip over as the permafrost below melts away. Scientists are unsure when and how much of Alaska's permafrost will thaw. But new data shows that permafrost "is not as stable as people thought," says Vladimir Romanovsky of the University of Alaska in Fairbanks.

Scientist says: "It's sobering to think of this magnificent landscape and how fundamentally it can change over a relatively short time period." -- Max Holmes, Wood Hole Research Center

Science editor writes: "As the Arctic continues to warm, it is tipping towards permafrost being a source of carbon released to the atmosphere." -- Hannah Osborne of the International Business Times (London, U.K.)

Study says: "It is virtually certain that human activities have contributed to Arctic surface temperature warming, sea ice loss since 1979, glacier mass loss, and Northern Hemisphere snow decline observed across the Arctic." – Canadian government report, August 2017