Seite - 77 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

3 ObservedandProjected Impacts fromExtremeWeatherEvents… 77 risk.Thehazards that are studied include tropical andextra-tropical cyclones, river flooding, coastalflooding, aswell as small scalephenomenasuchashailstorms. Exposureandvulnerabilityarealsoconsideredasimportantdriversoffuturerisks. Manybutnot all of these studiesalso integrateprojectionsof increasingpopulation andwealthorcapitalatriskinthequantitativeestimatesoffuturerisk.Acomparison of these estimates shows that for tropical cyclones and extra-tropical cyclones, the effects of future increases in exposure aremuch larger than from increasinghazard frequencyasaconsequenceofanthropogenicclimatechange(Bouwer2013).Some recent studies have analysed these signals together in a single analysis, such as Crompton et al. (2011). They show that for tropical cyclones in the USA, it will take at least until the end of this century before the effects from anthropogenic climate change can be disentangled from the loss record.Muis et al. (2016) show for Indonesia that coastal and riverflood risk in the futurewill be largelydrivenby increasingexposure.Preston (2013) shows forvariousweatherhazards in theUSA that exposure potentially will have amajor impact on losses until the year 2050. Straderet al. (2017) showfor tornadorisk, that increasingexpansionofurbanareas in theUSoutweighs theeffectsof increasingsevereweatheroccurrence. Only very few studies have analysed the effects of a further decline in vulnera- bility, as a result of increasing risk reductionandadaptionefforts, in comparison to projectedfutureclimatechange.Jongmanetal. (2015)showsthatwhenconsidering vulnerability reduction (e.g., throughadaptationanddisaster risk reduction), future absolutelossesfromriverfloodingintermsoflossoflifeandmonetaryimpactscould be substantially reduced, at the global scale thanwithout adaptation, and under an optimistic scenario even declining, compared to today’s risks. Also,Mechler and Bouwer (2015) show for Bangladesh that increases in risks are potentially lower whendynamicvulnerability is considered. Theseprojectionstudies imply that forLossandDamage, itwill remaindifficult whichelementsoftheactuallossesfromextremeweatherareattributedtogreenhouse gas emissions;first of all, increasingexposure could still play adominant role.But in addition, successful vulnerability reduction could increasingly lead to a lowered paceof risk increases, compared to thepast.Changesareobserved in the frequency ofseveralweatherextremes,andanthropogenicclimatechangeisanimportantdriver for several of these.Also, losses, includingmonetary losses, fromextremeweather eventshaveincreased,ascanbeseenfromseveralobservationalrecords.Therecords of lossesdiscussedaboveare focusedonmonetary losses,while severalother types ofimpacts, includingnon-monetiseddamagesandirreversibleimpactsfromextreme weather, areunderrepresented, complicating theassessmentof lossesanddamages. Studies into drivers of losses fromextremeweather show that increasing exposure hasbeenthemost importantdriver, throughincreasingpopulationandcapitalassets. Anthropogenic climate change is currently not an important driver for changes in lossesfromeventsrelatedtoextremewind,rainfall,andflooding,exceptperhapsfor convectiveweather events (thunderstorms and hail). Other extremeweather types (suchasextremeheat)havenotbeenaddressed in thischapter, andmonetary losses arerarelyassessedforextremetemperatures. It isknownthatanthropogenicclimate changeisincreasingheatwavefrequency,andmortalityandmorbidityhavebeenhigh