Change and variation in the thermal state of permafrost in Nunavut

The Canadian Arctic is warming faster than the global average and changes in permafrost conditions may affect communities and infrastructure in the north. Permafrost monitoring provides essential baseline information to inform land-management activities and northern infrastructure planning. The Geological Survey of Canada has measured ground temperature at Alert since 1978, and established permafrost monitoring sites near several communities in 2008-09 in collaboration with the Nunavut Government and community members. Analysis of ground temperature time-series facilitates characterization of the permafrost thermal state. Ground temperature closely tracks air temperature because of limited surface buffering due to sparse vegetation and thin surficial deposits. Results show that in the high Arctic at Alert, ground temperatures at 24 m depth have increased at a rate of 0.4ºC per decade since 1978, but the rate has increased to 0.6ºC per decade since 2000, reflecting the greater warming observed in air temperature records. At Resolute Bay, permafrost at 15 m depth has warmed by 1.1ºC per decade since 2008. Further south on Baffin Island, permafrost has warmed by 0.4 to 0.7°C per decade over the same period. The impact of shorter-term variations in climate are also superimposed on the general permafrost warming trend.