High Potential for Loss of Circumpolar Pingos, Ice-wedge Polygons and Rock Glaciers due to Climate Change

• Main Authors: Karjalainen, Olli, Luoto, Miska, Aalto, Juha Antero, Etzelmüller, Bernd, Grosse, Guido, Jones, Benjamin M., Lilleoren, Karianne S., Hjort, Jan
• Format: Conference Object
• Language: unknown
• Published: AGU 2019
• Subjects: Ice; permafrost; Thermokarst; wedge*
• Online Access: https://epic.awi.de/id/eprint/50805/; https://hdl.handle.net/10013/epic.557c2951-fa09-4cff-a099-bfd6cd0cdfa6

Ground ice dynamics bear crucial importance in the hydrologic and ecologic development of permafrost landscapes, but also create characteristic landforms. So far, spatial distributions and sensitivities of these landforms under changing climates have not been assessed at a circumpolar scale. We integrated pingo (n = 9,709), ice-wedge polygon (n = 861) and rock glacier (n = 4,035) observations and geospatial data on environmental conditions into a statistical modelling framework to produce high-resolution (~1km2) distribution maps of permafrost landform occurrence across the Northern Hemisphere in current and future climates. We found that on average more than one-fifth of the potential environmental spaces might be lost by mid-century under a moderate human-induced greenhouse emission forcing (representative concentration pathway, RCP4.5). Thereon, environmental spaces continue to shrink to less than 50% of the current coverage by 2061–2080, given a ‘business-as-usual’ (RPC8.5) climate-forcing scenario. Forecasted losses of suitable regions for pingos and ice-wedge polygons were attributed to increases in precipitation and thawing-season air temperatures. Rock glaciers were dominantly air temperature-driven. Our results are congruent with the site- and regional-scale observations of rapid geomorphic responses to ongoing climate change, and for the first time demonstrate large regional shifts in potential landform distributions at a circumpolar scale. These findings suggest that extensive regions are undergoing drastic changes in Earth surface processes, e.g. ground ice thaw, which are prone to cause thermokarst and threats to infrastructure development. Despite sophisticated modelling frameworks and increased data availability, circumpolar-scale geomorphological distribution modelling is still highly dependent on the quality of used geospatial data and the completeness of sampling, especially in heterogeneous environments. Based on the magnitude of climatic sensitivities of permafrost landforms, we suggest that geomorphic responses should be closely integrated into assessments of climate change impacts on natural and human systems.