When ice-rich permafrost thaws, it can collapse to form different landscapes call thermokarst. Huge lakes, sometimes over 5,000 hectares, form on flat terrains, while wetlands form on flat terrains of peat-rich soil. Hilly landscapes form when the soil collapses on a slope. All these features contribute to the release of greenhouse gases in different ways. The researchers' new map will help future scientists investigate thermokarst on a large scale. Images courtesy of Gustaf Hugelius and Britta Sannel