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TitreResponse of permafrost in Canada to a changing climate
AuteurLewkowicz, A G; Smith, S L; Burn, C R
SourceProceedings, Our Warming Planet, IAMAS-IAPSO-IACS Joint Assembly MOCA-09/Processus, Le réchauffement de notre planète, AIMSA-AISPO-AISC assemblée conjointe, MOCA-09; par MOCA-09 Committee; 2009.
Séries alt.Secteur des sciences de la Terre, Contribution externe 20080649
RéunionIAMAS-IAPSO-IACS Joint Assembly MOCA-09; Montreal; CA; juillet 19-29, 2009
Sujetspergélisol; fluctuations climatiques; géologie de l'environnement
ProgrammeLes sciences de la Terre à l'appui de la caractérisation, à l'échelle nationale, des impacts des changements climatiques sur la masse continentale canadienne, Géosciences de changements climatiques
LiensMOCA-09 website
Résumé(disponible en anglais seulement)
The impacts of climate change on permafrost, a key component of the cryosphere in Canada, are not always obvious or direct. However, results from a network of permafrost monitoring sites, largely developed by the Geological Survey of Canada and enlarged with university researchers and other partners during the International Polar Year, show that warming of permafrost has occurred. In the Yukon, new boreholes in mountainous terrain indicate that ground temperatures are affected by both elevation and local topography. These observations are linked to results from a network of about 90 air and ground surface temperature measurement sites across the Territory which demonstrate
the importance and strength of air temperature inversions in reversing lapse rates in the winter months, and reducing them to very low values on an annual basis. In the southern part of the Yukon, a resurvey of sites along the Alaska Highway that were examined in 1964 shows that substantial loss of permafrost has occurred over the past 45 years, but
that thin permafrost has persisted at some sites. On Herschel Island in the Beaufort Sea, measurements and modeling suggest that permafrost temperatures have increased substantially since the end of the nineteenth century. In the Mackenzie Valley, significant warming has been observed along the Norman Wells pipeline route over the past 25
years. These results illustrate that permafrost response to past and future climate change are complex and depend upon antecedent ground temperatures, ice contents and vegetation, as well as on the magnitude of the climatic change.