Climatic conditions in northern Canada: past and future.

This article reviews the historical, instrumental, and future changes in climate for the northern latitudes of Canada. Discussion of historical climate over the last 10 000 years focuses on major climatic shifts including the Medieval Warm Period and the Little Ice Age, and how these changes compare with those most recently experienced during the period of instrumental records. In reference to the latter, details are noted about observed trends in temperature and precipitation that have been recorded over the last half century, which exhibit strong west to east and north to south spatial contrasts. A comprehensive review of future changes is also provided based on outputs from seven atmosphere-ocean global climate models and six emission scenarios. Discussion focuses on annual, seasonal, and related spatial changes for three 30-year periods centered on the 2020s, 2050s, and 2080s. In summary, substantial changes to temperature and precipitation are projected for the Canadian North during the twenty-first century. Although there is considerable variability within the various projections, all scenarios show higher temperature and, for the most part, increasing precipitation over the entire region.