Aerial view of thermokarst melt at the Yukon Delta National Wildlife Refuge

Photo By/Credit
Scott Covington/USFWS
Date Shot/Created
Media Usage Rights/License
Public Domain
At Yukon Flats National Wildlife Refuge, the formation of thermokarst lakes can be seen from the air. Thermokarst lakes form when ice-rich permafrost melts, which also releases carbon dioxide and methane, two gases that significantly contribute to global warming.