The United Nations Environment Programme (UNEP) has published a Report on the status of the global permafrost regions in the Arctic, Siberia and in the high mountain regions. The report seeks to inform a broad audience about permafrost and communicate to decision-makers and the general public the implications of changing permafrost in a warming climate.
Permafrost consists of an active layer of up to two metres in thickness and the permanently frozen soil beneath. Should the active layer increase in thickness due to warming, huge quantities of organic matter stored in the frozen soil would begin to thaw and decay, releasing large amounts of CO₂ and methane into the atmosphere. This process will operate in a feedback loop known as the permafrost carbon feedback, which has the effect of increasing surface temperatures and thus accelerating the further warming of permafrost - a process that would be irreversible on human timescales.
The report says most of the recent climate projections are biased on the low side relative to global temperature because the models do not at this time include the permafrost carbon feedback. The report recommends a special IPCC assessment on permafrost and the creation of national monitoring networks and adaptation plans as key steps to deal with potential impacts of this significant source of emissions, which may become a major factor in global warming.