ClimateChange Assessment Guide.pdf - University of Waterloo

Guide for Assessment of Hydrologic Effects of Climate Change in Ontario10Table 2.4 Projected changes in extreme events and their likelihood of occurring (Christensen et al., 2007b)Extreme Projected Change Likelihood ofOccurrence/Outcome 1TemperaturerelatedMoisture-relatedTropical cyclonesExtra tropical• Higher monthly absolute maximum of daily maximum temperatures,more hot/warm summer days•Longer duration, more intense, more frequent heat waves/hot spotsin summer• Higher monthly absolute maximum of daily minimum temperatures;more warm and fewer cold nights• Higher monthly absolute minimum of daily minimum temperatures• Higher monthly absolute minimum of daily maximum temperatures,fewer cold days• Fewer frost days• Fewer, shorter, less intense cold extremes in winter• Reduced diurnal temperature range• Temperature variability in winter reduced, summer increased• More intense precipitation events• Increase in number of wet days in winter• Increase length and frequency of dry spells• Increase in continental drying and associated risk of drought• Increase in peak wind intensities• Increase in mean and peak precipitation intensities• Decrease in total number of storms; a poleward shift in storm trackswith changes in wind, precipitation and temperature patterns• Increase number of intense cyclones and strong winds• very likely• very likely• very likely• very likely• likely• very likely• very likely/likely• likely• likely• very likely• likely at highlatitudes• very likely over NewZealand, Australia,Mediterranean; likelyin subtropics• likely at mid-latitudes• likely• likely• likely• likely1Likelihood as used in this table refers to a probabilistic assessment of some well-defined outcome having occurred or occurring in the future.The uncertainty in specific outcomes is assessed using expert judgment and statistical analysis of a body of evidence (e.g., observations ormodel results). The following likelihood ranges are used to express the assessed probability of occurrence: virtually certain >99%; extremelylikely >95%; very likely >90%; likely >66%; more likely than not > 50%; about as likely as not 33% to 66%; unlikely