The northern permafrost region contains approximately 50% of the estimated global below-ground organic carbon pool and more than twice as much as is contained in the current atmospheric carbon pool. The sheer size of this carbon pool, together with the large amplitude of predicted arctic climate change implies that there is a high potential for global-scale feedbacks from arctic climate change if these carbon reservoirs are destabilized. In addition to the carbon available for microorganisms to produce methane and carbon dioxide in the active layer of permafrost landscapes, carbon and free methane gas stored for hundreds or thousands of years in permafrost are increasingly liberated by talik formation under thaw lakes and by coastal erosion. The role of methane emission due to the destabilization of gas hydrates within or under the permafrost along with the Arctic warming is still almost unknown and can only be roughly estimated. Significant gaps exist in our current state of knowledge that prevent us from producing accurate assessments of the vulnerability of the arctic permafrost to climate change, or of the implications of future climate change for global greenhouse gas (GHG) emissions. Several international research projects, as the European PAGE21 project “Permafrost and its global effects in the 21st century” which directly address these questions through a close interaction between monitoring activities, process studies and modeling on the pertinent temporal and spatial scales just started. PAGE21 is directly linked to the Japanese-EU cooperative GRENE-TEA project, the Canadian ADAPT project and the Nordic Center of Excellence DEFROST project of the Scandinavian countries.