| Titre | Temperature and precipitation across Canada |
| Télécharger | Téléchargements |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Zhang, X; Flato, G; Kirchmeler, M; Vincent, L; Wan, H; Wang, X; Rong, R; Fyfe, J; Li, G; Kharin, V V |
| Source | Canada's changing climate report; par Bush, E (éd.); Lemmen, D S (éd.); 2019 p. 112-193, https://doi.org/10.4095/327811  Accès ouvert |
| Liens | Online - En ligne (interactive - interactif)
|
| Liens | Canada's Changing Climate Report
- Additional Information
|
| Année | 2019 |
| Éditeur | Gouvernement du Canada |
| Document | livre |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/327811 |
| Media | papier; en ligne; numérique |
| Référence reliée | Cette publication est contenue dans Canada's
changing climate report |
| Référence reliée | Cette publication est une traduction de Les
changements de température et de précipitations au Canada |
| Formats | pdf |
| Province | Colombie-Britannique; Alberta; Saskatchewan; Manitoba; Ontario; Québec; Nouveau-Brunswick; Nouvelle-Écosse; Île-du-Prince-Édouard; Terre-Neuve-et-Labrador; Territoires du Nord-Ouest; Yukon; Nunavut;
Région extracotière du nord; Région extracotière de l'est; Région extracotière de l'ouest; Canada |
| SNRC | 1; 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 OENS | -141.0000 -50.0000 90.0000 41.7500 |
| Sujets | climat; climatologie; effets climatiques; neige; glace; pergélisol; glace fossile; glace marine; glaciers; eaux de surface; rivières; lacs; temperature; précipitation; températures au sol; océanographie;
climat arctique; Cordillère canadienne; Changement climatique; Calotte glaciaire; Eau douce; effets cumulatifs; Nature et environnement; géologie des dépôts meubles/géomorphologie; géologie de l'environnement; hydrogéologie |
| Illustrations | cartes de localisation; graphiques; modèles; graphiques; photographies; tableaux; histogrammes |
| Programme | Les impacts et l'adaptation liés
aux changements climatiques |
| Programme | Les impacts et l'adaptation liés aux changements climatiques Le Canada dans un climat en changement |
| Diffusé | 2019 04 02; 2020 12 08 |
| Résumé | (Sommaire disponible en anglais seulement)
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. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Le présent chapitre évalue les changements observés et projetés de température et de précipitations pour le Canada et présente les analyses de
certains événements extrêmes récents ainsi que leurs causes. |
| GEOSCAN ID | 327811 |
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