This paper provides a snapshot of the permafrost thermal state in the Nordic area obtained during the International Polar Year (IPY) 2007-2009. Several intensive research campaigns were undertaken within a variety of projects in the Nordic countries to obtain this snapshot. We demonstrate for Scandinavia that both lowland permafrost in palsas and peat plateaus, and large areas of permafrost in the mountains are at temperatures close to 0°C, which makes them sensitive to climatic changes. In Svalbard and northeast Greenland, and also in the highest parts of the mountains in the rest of the Nordic area, the permafrost is somewhat colder, but still only a few degrees below the freezing point. The observations presented from the network of boreholes, more than half of which were established during the IPY, provide an important baseline to assess how future predicted climatic changes may affect the permafrost thermal state in the Nordic area. Time series of active-layer thickness and permafrost temperature conditions in the Nordic area, which are generally only 10 years in length, show generally increasing active-layer depths and rising permafrost temperatures.

Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150

Supplement to: Christiansen, Hanne Hvidtfeldt; Etzelmüller, Bernd; Isaksen, Ketil; Juliussen, H; Farbrot, Herman; Humlum, Ole; Johansson, M; Ingeman-Nielsen, Thomas; Kristensen, L; Hjort, J; Holmlund, Per; Sannel, A Britta K; Sigsgaard, C; Åkerman, H J; Foged, N; Blikra, Lars Harald; Pernosky, M A; Ødegård, Rune Strand (2010): The Thermal State of Permafrost in the Nordic Area during the International Polar Year 2007-2009. Permafrost and Periglacial Processes, 21(2), 156-181