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TitleTemperature and precipitation across Canada
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorZhang, X; Flato, G; Kirchmeler, M; Vincent, L; Wan, H; Wang, X; Rong, R; Fyfe, J; Li, G; Kharin, V V
SourceCanada's changing climate report; by Bush, E (ed.); Lemmen, D S (ed.); 2019 p. 112-193, (Open Access)
LinksOnline - En ligne (interactive - interactif)
LinksCanada's Changing Climate Report - Additional Information
PublisherGovernment of Canada
Mediapaper; on-line; digital
RelatedThis publication is contained in Bush, E; Lemmen, D S; (2019). Canada's changing climate report
RelatedThis publication is a translation of Zhang, X; Zhang, X; Flato, G; Flato, G; Kirchmeler, M; Kirchmeler, M; Vincent, L; Vincent, L; Wan, H; Wan, H; Wang, X; Wang, X; Rong, R; Rong, R; Fyfe, J; Fyfe, J; Li, G; Li, G; Kharin, V V; Kharin, V V; (2019). Les changements de température et de précipitations au Canada, Rapport sur le climat changeant du Canada
File formatpdf
ProvinceBritish Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut; Northern offshore region; Eastern offshore region; Western offshore region
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-141.0000 -50.0000 90.0000 41.7500
SubjectsNature and Environment; surficial geology/geomorphology; environmental geology; hydrogeology; climate; climatology; climate effects; snow; ice; permafrost; ground ice; sea ice; glaciers; surface waters; rivers; lakes; temperature; precipitation; ground temperatures; oceanography; climate, arctic; Canadian Cordillera; climate change; ice caps; fresh water; cumulative effects
Illustrationslocation maps; graphs; models; plots; photographs; tables; histograms
ProgramClimate Change Impacts and Adaptation Program, Canada in a Changing Climate
Released2019 04 02; 2020 12 08
Temperature and precipitation are fundamental climate quantities that directly affect human and natural systems. They are routinely measured as part of the meteorological observing system that provides current and historical data on changes across Canada. Changes in the observing system, such as changes in instruments or changes in location of the measurement site, must be accounted for in the analysis of the long-term historical record. The observing system is also unevenly distributed across Canada, with much of northern Canada having a very sparse network that has been in place for only about 70 years. There is very high confidence1 that temperature datasets are sufficiently reliable for computing regional averages of temperature for southern Canada from 1900 to present and for northern Canada2 from 1948 to present. There is medium confidence that precipitation datasets are sufficiently reliable for computing regional averages of normalized precipitation anomalies (departure from a baseline mean divided by the baseline mean) for southern Canada from 1900 to present but only low confidence for northern Canada from 1948 to present. These datasets show that temperature in Canada has increased at roughly double the global mean rate, with Canada's mean annual temperature having risen about 1.7ºC (likely range 1.1ºC -2.3ºC) over the 1948- 2016 period. Temperatures have increased more in northern Canada than in southern Canada, and more in winter than in summer. Annual mean temperature over northern Canada increased by 2.3ºC (likely range 1.7ºC-3.0ºC) from 1948 to 2016, or roughly three times the global mean warming rate. More than half of the warming can be attributed to human-caused emissions of greenhouse gases. Climate models project similar patterns of change in the future, with the amount of warming dependent on future greenhouse gas emissions. A low emission scenario (RCP2.6), generally compatible with the global temperature goal in the Paris Agreement, will increase annual mean temperature in Canada by a further 1.8ºC by mid-century, remaining roughly constant thereafter. A high emission scenario (RCP.8.5), under which only limited emission reductions are realized, would see Canada's annual mean temperature increase by more than 6ºC by the late 21st century. In all cases, northern Canada is projected to warm more than southern Canada, and winter temperatures are projected to increase more than summer temperatures. There will be progressively more growing degree days (a measure of the growing season, which is important for agriculture) and fewer freezing degree days (a measure of winter severity), in lock-step with the change in mean temperature. There is medium confidence, given the available observing network across Canada, that annual mean precipitation has increased, on average, in Canada, with larger relative increases over northern Canada. Climate models project further precipitation increases, with annual mean precipitation projected to increase by about 7% under the low emission scenario (RCP2.6) and 24%15 under the high emission scenario (RCP.8.5) by the late 21st century. As temperatures increase, there will continue to be a shift from snow to rain in the spring and fall seasons. While, in general, precipitation is projected to increase in the future, summer precipitation in parts of southern Canada is projected to decrease by the late 21st century under a high emission scenario. However, there is lower confidence in this projected summer decrease than in the projected increase in annual precipitation. There is high confidence in the latter because different generations of models produce consistent projections, and because increased atmospheric water vapour in this part of the world should translate into more precipitation, according to our understanding of physical processes. The lower confidence for summer decreases in southern Canada is because this region is at the northern tip of the region in the continental interior of North America where precipitation is projected to decrease, and at the transition to a region where precipitation is projected to increase. The atmospheric circulation-controlled pattern is uncertain at its edge, and different models do not agree on the location of the northern boundary of this pattern. The most serious impacts of climate change are often related to changes in climate extremes. There have been more extreme hot days and fewer extreme cold days - a trend that is projected to continue in the future. Higher temperatures in the future will contribute to increased fire potential ("fire weather"). Extreme precipitation is also projected to increase in the future, although the observational record has not yet shown evidence of consistent changes in short-duration precipitation extremes across the country. The changing frequency of temperature and precipitation extremes can be expected to lead to a change in the likelihood of events such as wildfires, droughts, and floods. The emerging field of "event attribution" provides insights about how climate change may have affected the likelihood of events such as the 2013 flood in southern Alberta or the 2016 Fort McMurray wildfire. In both cases, human-caused greenhouse gas emissions may have increased the risk of such extreme events relative to their risk in a pre-industrial climate.
Summary(Plain Language Summary, not published)
This chapter assesses observed and projected changes in temperature and precipitation for Canada, and it presents analyses of some recent extreme events and their causes.

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