Seite - 64 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

64 L.M.Bouwer 3.1 Introduction 3.1.1 Impacts fromExtremeWeather Impacts from anthropogenic climate change are often equatedwith impacts from weather-relatednatural hazards, suchasfloods, droughts andwindstorms.Extreme weather events can lead to substantial impacts, including loss of life, damages to buildings,agriculturalproductionandnaturalcapital,aswellaslongertermeconomic effects.ThediscussiononLossandDamagefromclimatechangethereforewarrants adiscussionon theextent towhich increases in impacts fromextremeweatherhave alreadyoccurred,whatimpactscanbeexpectedinthefuture,andwhichlossescannot bepreventedor reduced through risk reductionandadaptation. In this chapter “climate change” is defined according to the definition by the IntergovernmentalPanel(IPCC2012),whichincludesbothnaturalvariability,aswell ashumaninducedclimatechangefromanthropogenicforcingsuchasgreenhousegas emissions.Lossesanddamageshavevaryingdefinitions,andwediscuss theseinthe lightofcurrentunderstandingofimpactsfromweatherextremes.Asexplainedinthe introductorychapter (Mechler et al. 2018), “losses” refer tomonetary losses,while “damages”aremeant tocovernon-monetary impacts aswell as irreversibleeffects. Losses fromextremeweather can includeboth types;monetary losses (damages to buildingsandotherproperty thatcanberepairedorreplaced),aswellnon-monetary impactssuchas lossof life,health impacts,andirreversibledamagessuchascoastal erosion, ecosystem impacts and societal impacts (for instance retreat after severe flooding). Current understanding shows that the changes in impacts fromextremeweather hazardsare largelymoderatedbytheextent towhichhumansandassetsareexposed to these hazards, and towhat extent they are vulnerable or sensitive to these haz- ards.This implies that apart from the actual occurrenceof thehazards, the level of impacts—relevant to the Loss andDamage debate—is influenced by non-climatic factors.Quantitative riskassessmentmethodsandapproachespracticedsincemany decades in natural hazard research can help to assess risk fromweather and geo- physical extremes using the combination of these processes. The framework that combines theseelementsofhazard,exposure, andvulnerabilityasdevelopedby the IPCC(2012)hasnowbecomewidelyacceptedbytheclimatechangeresearchcom- munity to understand and study the occurrence aswell as temporal changes in the impactsfromextremes(e.g.Huggeletal.2013;seeframeworkdepictedinFig.3.1). Thehazarddriver is influencedbychanges in climate; both fromanthropogenic climatechange, resulting fromgreenhousegasemissions, aswell asnatural climate variability.Exposure is influencedbychanges indevelopment, includingpopulation growth and economic development that lead to increased accumulation of people andcapitalassets in locations thatareat riskfromnaturalhazards.Vulnerabilityand exposuremaychangebecauseofadaptationandrisk reductionactions that increase the protection fromweather hazards and reduce sensitivity to these extremes that would otherwise results in negative impacts. Governance can influence land-use