Page - 136 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

136 R.A. Jameset al. Fig.5.8 Sensitivity of estimated contributions to global mean surface temperature increase to the choice of forcing components included in attribution analysis. CO2FF: CO2 from fossil-fuel combustionandcementproduction.LUC:Landusechange.KP:KyotoProtocolgases(CO2,CH4, N2O,HFC,SF6,PFC).ALLPOS:Allwarmingcomponents. SourceSkeieet al. (2017) databases and inventories are used and often assumptions and inter/extrapolations areneeded (seeSkeieet al. 2017). The results of these studies depend strongly on various choices taken during the analysis. Among the choices that have to bemade are start and end dates for emissions that are considered,when tomeasure the effect of the emissions, what indicatorofclimatechangeischosen(temperature,precipitation,extremes,sealevel rise, etc.), which drivers (GHGs, aerosols, land use changes) are included, how to frametheemissionsbytheselectedentities(extraction/territorial/consumptionbased emissions), andwhether thecontributions shouldbenormalisedbypopulationsize. An alternative could also be to normalise the contributions by theGrossDomestic Product (GDP)of thecountries.Figure5.8 showshowthechoiceofemissioncom- ponents includedcan impact the resultingcalculationsofhowmucheach regionor country has contributed to change in globalmean surface temperature up to 2012 (Skeieet al. 2017). AsdiscussedbySkeieetal. (2017),andFuglestvedtandKallbekken(2015) there is no simple and single answer to the contributionquestion.Thus, it is not straight- forward to ask howmuch a particular country, company, or sector contributed to observed global warming. The answer varies depending on many choices in the methodology, and these choices are associatedwithmany open value-related and ethical questions.Scientistsmight thereforebest support policy-makersbypresent- ing a spectrumof results showinghow the calculated contributions vary according tovariouschoices. Anatural researchquestion toask iswhether itwillbepossible togofurtherand attributeotherimplicationsofclimatechangetonations’emissions.Ottoetal.(2017) for thefirst timeexplore thelinkbetweenemissionsfromcountries toradiativeforc- ingandtemperaturecontributions,andchangesintheprobabilityofextremeweather