Page - 135 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

5 Attribution:HowIs ItRelevant forLoss… 135 bution (StoneandAllen2005;Stoneet al. 2013;Huggel et al. 2015a;Hansenet al. 2016),whichmightbeuseful for further research.There isaquestionaboutwhether this constitutes true “end-to-end” attribution in the case of L&D. Do all climate changeimpactsconstituteL&D?ItisnotoriouslyunclearexactlyhowL&Dshouldbe defined,but it isperhapsworthconsideringvariousotherelementswhichmightcon- tributetoan“end-to-end”attributionofL&D,includingextendingthe“causalchains” from emissions to emitters (Sect. 5.3.3), and towards disaster losses (Sect. 5.3.4). It is alsoworth consideringwhichof the impacts attributed (in e.g. Fig. 5.7)might alreadybeconsideredL&D.Recenteventattributionstudieshaveanalysedmonetary lossesfromflooding(Schalleretal.2016);andlossoflifefromcold-andheat-related events (Christidisetal.2010;Mitchelletal.2016).Huggeletal. (2016a)alsoexam- inetheHansenandStone(2016)data(Fig.5.7) toconsiderwhichimpactsconstitute irreversiblelosses,findingevidencefortheattributionofirreversiblelossofglaciers, coral reefs, or livelihoodsofArctic communities. 5.3.3 AttributingAnthropogenicForcing toRegions, Countries, andSectors IPCC(2013) stated “Human influenceon the climate system is clear.”This overar- chingstatementcanbedecomposedontheresponsesideof thecause-effectchain in termsofvarious typesof impactsandtheir regionaldistribution(Sects.5.3.1,5.3.2). But it isalsopossible todosoonthedriverside—alongseveraldimensions.Firstly, therearedifferentemissionsandsurfacechangesthatperturbtheradiativebalanceof the earth-atmosphere systemandcause radiative forcing; greenhousegases suchas CO2,CH4andN2O,aerosolssuchassulphateandblackcarbon,andalbedochanges from land surface changes. Secondly, these factors also have a regional resolution; i.e., the emissions and changes in albedo from landuse changes canbedistributed to regionsandnations, andeconomic sectors.Thirdly, thesechangeshaveoccurred atdifferentpoints in time;e.g.earlydeforestationandcoalburningversus lateemis- sions frommoremodern sectors (e.g. aviation) and technologies (e.g. halogenated gases). Several studies have quantified contributions to climate change by regions (denElzenetal.2005),nations(e.g.Matthews2016;Skeieetal.2017), sectors (e.g. Fuglestvedt et al. 2008)andevencompanies (Heede2014). To investigate the contributions to climate change, simple climate models are used to test the influence of specified quantities of emissions, or types of radiative forcing,onclimaticchanges,primarilyglobal temperature.Contributions toclimate change areoftendefined in counterfactual terms; i.e., howwould the change in the chosen climate indicator (usually globalmean surface temperature) be different if a particular subset of emissionswere removed?A large number of simulations are usedtotestmanydifferentsubsetsofemissions.Duetonon-linearitiestheindividual contributions do not necessarily add up to 100%and there are variousmethods to adjust for this.Availability of emissions data is also a key issue.Various emission