ClimateChange Assessment Guide.pdf - University of Waterloo

Guide for Assessment of Hydrologic Effects of Climate Change in Ontario12Table 2.5 Climate changes observed and projected for Canada (as summarized in (Bruce et al., 2006b)Variable Observed Changes Projected change by the 2050s (unlessotherwise noted)Canadian MeanTemperaturesOntario MeanTemperaturesTotal Precipitation> 1°C increase (20th century) 2 to 4°C increase (CGCM 1975-1995 to2040-2060)0.6°C increase2 to 3°C increaseMore at mid-latitudes; significantly more at highaltitudes 1950-19980-20% increase in north, slightly less in midcontinentin summer (HadCM3 2040-2060)Total Rainfall (Ontario) +1% per decade +1% per decadeDate of Spring Breakup 82% basins earlier (1967-1996) EarlierExtreme RainfallUp to 20% increase in heavy 1-day falls in SE 2x frequency of heavy rains for 2xCO 2(CGCM)Canada (early summer)Extreme Rain Events +5 to 7% per decade, especially in spring (May) +5% per decade(Ontario)Severe Winter Storms Increased intensity +15-20% in intensityWater VapourStatistically significant increase over North IncreaseAmerican except northeast CanadaSevere Winter Storms Increased frequency and intensity N of 60°N +15 to 20% for 2xCO 2(CGCM)Increased intensity S of 60°N (1959-1997)30 minute Extremes +5% per decade+4.6% per decade to 1996+5% per decadeDaily Extremes +7% per decade (M, J, J)+5% per decade to 1996Annual Rainfall +1 to 3% per decade +1% per decade+3% per decade (20-year return period)+2.5 to 6% per decade (rainfall probability