IPCC_Managing Risks of Extreme Events.pdf - Climate Access

Changes in Climate Extremes and their Impacts on the Natural Physical EnvironmentChapter 3Table 3-3 | Projected regional changes in temperature and precipitation (including dryness) extremes. See Figure 3-1 for definitions of regions (numbers indicated next to regions’ names). For assessments for small island states, referto Box 3-4. Projections are for the end of the 21st century versus the end of the 20th century (e.g., 1961-1990 or 1980-2000 versus 2071-2100 or 2080-2100) and for the A2/A1B emissions scenarios (except if noted otherwise).Late 20th-century extreme values (generally either 1961-1990 or ~1980-2000) are used as reference (see Box 3-1 for discussion). Codes for the source of modelling evidence: G: multiple GCMs; R: single RCM forced by single GCM;R: multiple RCMs forced by single GCM; R: multiple RCMs forced by multiple GCMs. T06 stands for Tebaldi et al. (2006), SW08b stands for Sheffield and Wood (2008b), and OS11 stands for Orlowsky and Seneviratne (2011).A. North America and Central AmericaRegionsTmax[WD = Warm DaysCD = Cold DaysRV20AHD: 20-year return value of annualmaximum hottest day](using late 20th-century extreme values asreference; see Box 3-1)Tmin[WN = Warm NightsCN = Cold Nights](using late 20th-century extreme valuesas reference; see Box 3-1)Heat Waves (HW)/Warm Spells (WS)(using late 20th-century extreme valuesas reference; see Box 3-1)Heavy Precipitation (HP)[HPD = Heavy Precipitation Days, e.g.,precipitation >95th percentile (p)%DP10 = Percentage of Days withPrecipitation >10 mmHPC = Heavy Precipitation Contribution,generally fraction from precipitation >95thpercentileRV20HP = 20-year return value of annualmaximum daily precipitation rates] (using late20th-century extreme values as reference; seeBox 3-1)Dryness[CDD = Consecutive Dry DaysSMA = (Simulated) Soil MoistureAnomalies; see Box 3-3 fordefinitions]All NorthAmerica andCentralAmericaW. NorthAmerica(WNA, 3)CentralNorthAmerica(CNA, 4)High confidence: WD very likely or likely toincrease and CD very likely or likely to decreasein all regions (Christensen et al., 2007; Meehlet al., 2007b; Karl et al., 2008; Fig. 3-3). Verylikely increase in RV20AHD in all regions exceptCAM (Fig. 3-5).Medium confidence: Largest increases in WD insummer and fall particularly over the UnitedStates; largest decrease in CD in Canada in falland winter (OS11).High confidence: WD very likely to increase andCD very likely to decrease in all seasons(Christensen et al., 2007; Karl et al., 2008;Clark et al., 2010; Fig. 3-3). Very likely increasein RV20AHD (Fig. 3-5).Medium confidence: Overall weaker signal inspring and winter for both CD and WD (OS11).RCM simulations for 2030–2039 consistentwith projected long-term increase in WD(Diffenbaugh and Ashfaq, 2010).High confidence: WD very likely to increase andCD very likely to decrease in all seasons(Christensen et al., 2007; Karl et al., 2008;Clark et al., 2010; Fig. 3-3). Very likely increasein RV20AHD (Fig. 3-5).Medium confidence: Weaker signal for CD inspring and winter (OS11). RCM simulations for2030–2039 consistent with projected long-termincrease in WD (Diffenbaugh and Ashfaq,2010).High confidence: WN very likely or likely toincrease and CN very likely or likely todecrease depending on subregion (T06;Christensen et al., 2007; Kharin et al., 2007;Meehl et al., 2007b; Karl et al., 2008; Fig. 3-4).Medium confidence: Largest increase in WNand decrease in CN in summer, particularlyin the United States (OS11).High confidence: WN very likely to increaseand CN very likely to decrease (T06;Christensen et al., 2007; Kharin et al., 2007;Meehl et al., 2007b; Karl et al., 2008; Fig. 3-4).Medium confidence: Largest WN increasesand CN decreases in summer (OS11).High confidence: WN very likely to increaseand CN very likely to decrease (T06;Christensen et al., 2007; Kharin et al., 2007;Meehl et al., 2007b; Karl et al., 2008; Fig. 3-4).High confidence to medium confidencedepending on subregion. High confidence:Likely more frequent, longer, and/or moreintense heat waves and warm spells over allNorth American subregions. Mediumconfidence in increase in warm spells in partof Central America, but lack of agreement insignal of change in heat waves (T06;Christensen et al., 2007; Karl et al., 2008;Clark et al., 2010; OS11).High confidence: Likely more frequent,longer, and/or more intense heat waves andwarm spells (T06; Christensen et al., 2007;Meehl et al., 2007b; Karl et al., 2008; Clarket al., 2010; OS11).Medium confidence: RCM simulations for2030–2039 and 2090–2099 consistent withprojected long-term increase in frequencyand/or intensity of HW (Diffenbaugh andAshfaq, 2010; Kunkel et al., 2010).High confidence: Likely more frequent,longer, and/or more intense heat waves andwarm spells (T06; Christensen et al., 2007;Karl et al., 2008; Clark et al., 2010; OS11).Medium confidence: RCM simulations for2030–2039 and 2090–2099 consistent withprojected long-term increase in frequencyand/or intensity of HW (Diffenbaugh andAshfaq, 2010; Kunkel et al., 2010).Low confidence to high confidence depending onregion and index: Likely increase in HP, includingHPD, HPC and RV20HP, over Canada and Alaska;Low confidence to medium confidence in the south(particularly CAM) due to smaller and lessconsistent changes, and inconsistencies between%DP10 (decreases in winter and spring) and otherindices (T06; Christensen et al., 2007; Kharin et al.,2007; Meehl et al., 2007b; Karl et al., 2008; OS11;Fig. 3-6).Low confidence to medium confidence dependingon subregion and index: Medium confidence inincrease in HPD/HPC over northern part of domain(Canada); low confidence due to no signal orinconsistent signal in HPD/HPC changes oversouthern part of domain (T06; Fig. 3-6). Mediumconfidence in increase in RV20HP (Fig. 3-7).Low confidence to medium confidence dependingon index:Low confidence in changes in HPD/HPC due toinconsistent or no signal (T06; Fig. 3-6).Medium confidence in increase in RV20HP (Fig. 3-7).Low confidence to mediumconfidence depending on region.Medium confidence regardingincrease in CDD, and SMA droughtin Texas and N. Mexico (T06;SW08b; Fig. 3-10). Low confidence:Inconsistent change in other regions(SMA, CDD) (T06; SW08b; Fig. 3-10).G G G G GLow confidence: Inconsistent signalin CDD and SMA changes (T06;SW08b; Fig. 3-10).G R G G R G GMedium confidence: Increase in CDDand decrease in SMA in southernpart of the domain (SW08b; Fig. 3-10). Low confidence: inconsistentsignal elsewhere (Fig. 3-10).G R G G R G GContinued next page196