Katey Walter Anthony, an ecologist at the University of Alaska-Fairbanks, dips her paddle into the water as her kayak glides across the lake. "Years ago, the ground was about three meters taller and it was a spruce forest," she says.

Big Trail Lake is a thermokarst lake, which means it formed due to permafrost thaw. Permafrost is ground that stays frozen year round; the permafrost in interior Alaska also has massive wedges of actual ice locked within the frozen ground. When that ice melts, the ground surface collapses and forms a sinkhole that can fill with water. Thus, a thermokarst lake is born.

Walter Anthony is a researcher collaborating with NASA's Arctic Boreal Vulnerability Experiment (ABoVE) project. She's studying the formation of these thermokarst lakes and how this process is caused by and contributes to Earth's changing climate.

"Lakes like Big Trail are new, they're young, and they are important because these lakes are what's going to happen in the future," she explained.

They're also belching methane—a potent greenhouse gas—into the atmosphere.

At first glance, Big Trail looks like any lake. But look closer and there's something disturbing the surface: bubbles.