According to a study led by the U.S. Geological Survey (USGS), large tundra fires cause top-down permafrost thaw, playing a major role in altering Arctic landscapes.

According to a study led by the U.S. Geological Survey (USGS), large tundra fires cause top-down permafrost thaw, playing a major role in altering Arctic landscapes.
This Landsat 8 image shows Mongolia's capital, Ulan Bator. The city sits in the valley of the Tuul River, which runs from the upper right corner to the lower left corner of the image. The Bogd Khan Mountain National Park is in the center of the image.