Permafrost landscapes are threatened by climate warming and degrade in different ways. This includes near surface processes such as active layer deepening, as well as extensive processes like thermal erosion, and development of thermokarst features. In the Siberian and North American late Pleistocene ice-rich yedoma, permafrost thaw processes cause surface subsidence of several tens of metres due to loss of ground ice. With thawing, currently freeze-locked organic matter can be mobilized and contribute to the carbon-climate feedback, which is a process of global significance if formerly inactive, fossil carbon is re-introduced into the active carbon cycle.