Page - 127 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

5 Attribution:HowIs ItRelevant forLoss… 127 pogenic climate change is influencing losses and damages, and steps are already beingmade to integrate these disciplines. For example, recentwork has estimated themonetary losses attributable to anthropogenic emissions fromdamage to hous- ing following the 2013/2014winter flooding in theUK (Schaller et al. 2016), and thenumberofheat-relateddeathsattributable toanthropogenicemissionsduringthe 2003Europeanheatwave (Mitchell et al. 2016). Herewe review fields of study that might contribute tomore such analyses in the future, for each giving a brief overview of how the science works, examples of the kind of attribution findings it can deliver, an evaluation of the strength of evidencewhich is currently available, and future directions in the field.Given the scale of the challenge,we cannot not hope to be comprehensive, but rather to give an introduction alongside references which could providemore detailed insights. Figure5.2summarisessomeofthecausalconnectionsbetweenanthropogenicactiv- ityandlossesanddamages,andillustratescontributionsfromthedifferentscientific fieldsdescribedinSects.5.3.1–5.3.4.Severalauthorshavedescribeda“causalchain” betweenanthropogenicemissions,climateandweather,andlocalimpacts(Stoneand Allen 2005;Hansen et al. 2016). Herewe show there aremany interacting causal chains,whichmightbeconceivedofasawebornetworkofnaturalandanthropogenic interactions. 5.3.1 AttributionofClimateChangeandExtremeWeather Events toAnthropogenicForcing Thescienceofattributingobservedclimateandweathertoexternaldrivers,including attribution of climate change trends, and attribution of extremeweather events, is the typeof researchwhichphysical climate scientists areusually referring towhen theyuse the term“attribution,”andthis isalsohow“attribution” isused in theIPCC WorkingGroupI (WGI) reports (Bindoffetal.2013).Here,attribution isdefinedas “the process of evaluating the relative contributions ofmultiple causal factors to a changeoreventwithanassignmentof statistical confidence” (Hegerl et al. 2010:2; Bindoff et al. 2013: 872).Theaim is to investigate the influenceofhuman-induced changesinGHGsandothershort-livedclimateforcers(SLCFs)onclimateorextreme weatherevents, relative to the influenceofotherdrivers, includingmodesofnatural climatevariability,solarvariability,andvolcaniceruptions.Thestudiesusuallyfocus onclimateandweather, and thereforedonotnecessarilyprovide informationabout impacts or losses anddamages, therefore the results aremost relevant for the links shown in the top left of Fig. 5.2.What follows is a brief overviewof the relevance of attribution research toL&D.Formore detailed information, several reviews are available (Hegerl andZwiers 2011;Bindoff et al. 2013; Stott et al. 2016;National AcademiesofSciences,Engineering, andMedicine2016). Until very recently climate change attribution studies analysed trends, most notably the increase inglobalmeansurface temperature. In theseattributionstudies,