In the northernmost region of the earth the arctic permafrost is melting at an accelerated rate. For more than a decade, an international team of researchers from ETH Zurich, the University of Alaska Fairbanks, and the German Aerospace Center have observed topographical pock marks—large depressions referred to as, "retrogressive thaw slumps." The slumps occur when permanently frozen layers of soil (ice-rich permafrost) melt leaving arctic hillslopes vulnerable to landslides. The landslides signal a risk for the potential release of carbon that has been stored in the permafrost for tens of thousands of years.