Seite - 293 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

12 IntegratedDisasterRiskManagementandAdaptation 293 Fig.12.2 Flood risk in Jakarta measured as annual expected damage. The vertical dashed line represents thepresentvalue.Thecolouredcurves representprobabilitydensity functions,obtained byfittinggammadistributions to20combinationsof climatemodels andemission scenarios, thus each representing the uncertainty in future precipitation extremes. Curves are shown with and without landsubsidence,with landuse (LU)ofyear2009andLUof2030, andwith lowandhigh sea level rise (SLR). SourceModified fromBudiyonoet al. (2016) systemvia construction and rehabilitationofdikes.This is donebycutting the risk curve, alsoknownas theexceedanceprobability-damagecurve, assuming that each polder will provide a standard of protection expressed as the return period of the event it canwithstand (e.g., a50-yearflood). ForHoChiMinhCity, theriskoffloodingisquantifiedunderpresentconditions, andunderscenariosofclimateandsocioeconomicchangeoverthe21stcentury.This city already suffers regular disruption to livelihoods and business due to seasonal floods,mostlyduetostormsurgesfromtheSouthChinaSeaandheavyprecipitation and riverdischarge. Theassessment includesanumberofstepswherequantitativeinformationispro- cessed(Fig.12.3).Following,asforJakarta,theriskdefinitioninSect.12.1,theflood hazard isquantifiedviahydrodynamicmodelling, for four returnperiods, theexpo- sure is represented by land use and population densitymaps, and the vulnerability is expressed invulnerabilitycurves that are specificof the landuse.Tosimulate the future, the framework incorporates: in thefloodmodelling, projections of sea level rise from regionalised projections relative to twoRCP emission scenarios, one of moderateandoneofhighgreenhousegasemissions; intheimpactmodellingprojec- tionsofsocio-economicgrowthfromtwoplausibleSharedSocioeconomicPathway (SSP) scenarios.Thesepressuresare scenario-dependent.