Our Climate, Our Permafrost

Canada has about one quarter of the world’s permafrost, underlying about half of our country. The North, especially the western Arctic, has had the most rapid climate warming, with annual temperatures at Inuvik, NWT, rising since the 1960s from -9.5 °C to above -6 °C. Adjustments in the precipitation regime are primarily to rainfall in early autumn. These indicators exceed projections made in 2000 for the magnitude of climate warming under the highest rate of greenhouse-gas emissions then thought likely. The consequences of such climate change for permafrost environments depend on the history of ice accumulation in the ground and distribution of such ice with depth. Permafrost is no longer in thermal equilibrium with the climate, as it was 50 years ago. Instead, there are sites where the response to climate change is only in terms of temperature and others where ground properties are changing. In some cases, the adjustments to terrain integrity are gradual but in others catastrophic. The primary direct costs associated with climate change effects on permafrost accrue from deterioration of infrastructure. In Yukon, for instance, the proportion of the operation and maintenance budget for transportation infrastructure associated with climate-related costs rose from 24% to 53% in 1994–2022.