Journal article

Twenty years of European mountain permafrost dynamics—the PACE legacy

  • Etzelmüller, Bernd Department of Geosciences, University of Oslo, Norway
  • Guglielmin, Mauro Department of Theoretical and Applied Sciences, Insubria University, Varese, Italy
  • Hauck, Christian Department of Geosciences, University of Fribourg, Switzerland
  • Hilbich, Christin Department of Geosciences, University of Fribourg, Switzerland
  • Hoelzle, Martin Department of Geosciences, University of Fribourg, Switzerland
  • Isaksen, Ketil Norwegian Meteorological Institute, Oslo, Norway
  • Noetzli, Jeanette WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland
  • Oliva, Marc Department of Geography, University of Barcelona, Spain
  • Ramos, Miguel Physics and Mathematics Department, Alcalá University, Spain
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  • Environmental Research Letters. - 2020, vol. 15, no. 10, p. 104070
English This paper reviews and analyses the past 20 years of change and variability of European mountain permafrost in response to climate change based on time series of ground temperatures along a south–north transect of deep boreholes from Sierra Nevada in Spain (37°N) to Svalbard (78°N), established between 1998 and 2000 during the EU-funded PACE (Permafrost and Climate in Europe) project. In Sierra Nevada (at the Veleta Peak), no permafrost is encountered. All other boreholes are drilled in permafrost. Results show that permafrost warmed at all sites down to depths of 50 m or more. The warming at a 20 m depth varied between 1.5 °C on Svalbard and 0.4 °C in the Alps. Warming rates tend to be less pronounced in the warm permafrost boreholes, which is partly due to latent heat effects at more ice-rich sites with ground temperatures close to 0 °C. At most sites, the air temperature at 2 m height showed a smaller increase than the near-ground-surface temperature, leading to an increase of surface offsets (SOs). The active layer thickness (ALT) increased at all sites between c. 10% and 200% with respect to the start of the study period, with the largest changes observed in the European Alps. Multi-temporal electrical resistivity tomography (ERT) carried out at six sites showed a decrease in electrical resistivity, independently supporting our conclusion of ground ice degradation and higher unfrozen water content.
Faculté des sciences et de médecine
Département de Géosciences
  • English
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