GEOSCAN Search Results: Fastlink


Title4. Changing Permafrost and its Impacts
AuthorRomanovsky, V E; Isaksen, K; Drozdov, D; Anisimov, O; Instanes, A; Leibman, M; McGuire, A D; Smith, S L; Walker, D
SourceSnow, water, ice and permafrost in the arctic (SWIPA) 2017 : Scientific report; 2017.
Alt SeriesEarth Sciences Sector, Contribution Series 20150459
PublisherArctic Monitoring and Assessment Program
Mediapaper; on-line; digital
File formatpdf
ProvinceNunavut; Northwest Territories; Yukon
AreaPolar regions; Greenland; Norway; Afghanistan; Iceland; Finland; Sweden; United Kingdom; United States
Lat/Long WENS -18.0000 0.0000 90.0000 66.0000
Subjectssurficial geology/geomorphology; modelling; climate, arctic; climate effects; climate; permafrost; temperature; ground temperatures; vegetation; coastal erosion; active layer monitoring
Illustrationsgraphs; tables; location maps; photographs
ProgramEssential Climate Variable Monitoring, Climate Change Geoscience
LinksOnline - En ligne
AbstractKey findings Since IPY in 2007-08, new record high ground temperatures have been observed at many permafrost observatories across the Arctic. The greatest temperature increase, more than 0.5°C, occurred in the colder permafrost of the Arctic and high Arctic. In warmer permafrost such as that in the southern and central Mackenzie Valley, in the Alaskan Interior, or in the discontinuous permafrost zone in Siberia and the Nordic region the temperature increase has been much smaller or not detectable. At some few locations (e.g. in the Alaskan Interior) permafrost temperature has even slightly decreased (typically by 0.1°C). Most of the regions where long-term active layer thickness (ALT) observations are available show an increase in ALT during the last 5 years. In northern Alaska, complete freeze-up of the active layer in the mid-1980s typically occurred in the first half of October but has shifted to the middle December in the first half of the 2010s; the average date of freeze-up increased by almost two months. At some locations (e.g. in the European North of Russia) permafrost degradation has been observed. Since the SWIPA 2011 report, there have been substantial efforts to evaluate large-scale models of permafrost dynamics across the circumpolar north, and we now have a better understanding of the range of uncertainty in projections associated with both the models themselves and with the future projections of climate change. Progress has also been made in modeling the effects of vegetation change on permafrost dynamics in response to changing climate and modelling the dynamics of sub-sea permafrost beneath the continental shelf of the Arctic Ocean. A significant increase in areas of water-filled polygonal troughs was reported in Northern Alaska and linked to climatic changes. However, no unified trends in thermokarst development associated with global warming have been observed across the Arctic.. Changes in thermokarst lake development are related to both regional and local environmental and climatic factors, including the moisture balance. Incorporation of thermokarst and thermo-erosion processes in complex land surface models will be important to fully capture future responses of permafrost dynamics in a warming Arctic and related climatic feedbacks. Geographic assessments of changes in bearing capacity for some of the largest settlements on permafrost in the Russian Arctic indicate significant reduction between 1970 and 2050, with the largest decrease in bearing capacity (75-95% relative to 1970) predicted for the southern fringes of the permafrost zone. The Prudhoe Bay oilfield (PBO) in Alaska and Bovanenkovo gas field (BGF) on the Yamal Peninsula of Russia have experienced recent changes in permafrost conditions due to a series of warm summers that triggered major increases in thermokarst in the PBO and themocirques near the BGF.
Summary(Plain Language Summary, not published)
This report is an update of the permafrost chapter of the Snow Water Ice and Permafrost in the Arctic document, published in 2012 by the Arctic Monitoring and Assessment Program. The report documents the changes in permafrost temperature and active layer thickness that have occurred over the last 5 years and places these in the context of the longer term record. In general, permafrost continues to warm and active layers have become thicker across the circumpolar north. New information is also presented on projections of future permafrost conditions, impacts of warming permafrost on natural and built environments and the measures to deal with the challenges presented by a changing climate. The report informs, by contributing to the scientific foundation, the Arctic Council Project 'Adaptation Actions for a Changing Arctic' and its evaluation of how adaptions to a changing permafrost conditions might occur and the development of adaption strategies in response to a changing climate.