Page - 356 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

356 A.MarkandyaandM.González-Eguino (UNEP2016). It states that the current internationally accepted best estimates for adaptationcostsare in theUS$70billiontoUS$100billionperyearrangefordevel- oping countries by 2050, according to aWorldBank (2010) study. This compares with the rangeofUS$147–970 in theTables14.3and14.4.TheUNEPreportnotes, however, that theWorldBank(2010) study isoutdatedandmore recentworkbased ontwoIAMs(AD-RICEandAD-WITCH)comesupwithestimatesofUS$200–450 billion (AD-WITCH) andUS$570–970 billion (AD-RICE). Thus, our range from theBoselloet al. analysis is similar to thatof theUNEP(2016) report. Other data on costs of adaptation andonL&Ddamagesworth noting areBond (2016)andRichardsandSchalatek (2017),whocite the followingestimates: • UNEP’sAdaptationGapReport(2014)estimatestheindicativecostsofadaptation and the residualdamages (lossesanddamages) forLDCsat~USD50billion/year by 2025/2030 and possibly double this value (USD100 billion/year) by 2050 at 2°C. • Baarsch et al. (2015) suggestLoss andDamagecosts (not needs) for developing countriesof around$400bn in2030, rising to$1–2 trillionby2050. • DARA(2012)estimates thesecosts tobe$4 trillion in2030. • AMCEN/UNEPAfrica’sAdaptationGap2Report (2015)with all cost effective adaptation inAfrica lossesanddamagesareestimatedat~USD100bnperyearby 2050 forwarmingbelow2°C,at leastdouble that ifwarminggoesabove4°C. Theseestimatescanbecomparedtotheresidualdamagesfigureswehavegivenin Sect.14.2,whichrangefrom$20–580billionin2030to$1.1–1.7trillionin2050.As Bond(2016)alsonotes,furtherworkisrequiredonthemethodologiesandprocesses for estimatingL&Dandassociatedfinance needs, aswell as non-economic losses. It is in relation to these that thenext sectionaddresses someof thekeyoutstanding issues.These include (i) issues relating to the timehorizonunderconsiderationand related uncertainty, and (ii) the relationship between adaptation expenditures and L&D. 14.5 Uncertainties in theEstimationofFutureDamages fromClimateChange inIAMs Recently, significant debate has emerged about the uncertainties (Pindyck 2013) associatedwith thequantificationof thedamages fromclimatechangeby IAMs. In theprevioussection,weprovidedarangefor theresidualdamagesunder“standard” climatic conditions. In this section, we show these damages (and, therefore, the residual damages)would change significantly if “tipping points” are considered in the analysis (Lenton et al. 2008, 2012). There ismuch uncertainty related to these processesand,therefore,theyhaverecentlystartedtobecapturedinIAMliteraturein termsof implications for adaptation (Stern2016)andmitigation (González-Eguino et al. 2016, 2017).We illustrate this through two key sources of uncertainty: the EquilibriumClimateSensitivity (ECS)parameter and thedamage function.