Page - 273 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

11 TheRoleof thePhysicalSciences inLossandDamage… 273 Alternatively,decisionmakerscanusethesedifferentscenariostoidentify‘robust’ strategies thatwouldworkwellundermostof thesescenarios (Lempert andCollins 2007;Hallegatte2009;Rangeret al. 2010a,b;Fankhauseret al. 2013;Weaveret al. 2013).Robustdecision-makingwasappliedtowatersupplymanagement inCalifor- nia (Groves et al. 2008) andFlood riskmanagement inHoChiMinhCityVietnam (Lempert et al. 2013) (seechapterbyBotzenet al. 2018). Other examples of how these strategies have been applied in different countries and sectors include theDutchDelta Programme, the LouisianaMaster Plan for a Sustainable Coast, and the ColoradoRiver Basin Supply andDemand Study (see Lempert andHaasnoot2017). Even thoughthesedecision-strategiescanbeofvalueforL&Ddecision-making, their applicationhas remained relativelyunder-explored in this context. In a broad sense there is clear merit in both science-driven and policy-driven approaches for L&Ddecisionmaking: scientific assessments are important for all threeL&Dgoals and shouldunderpin and inform thedecisionprocess.This is par- ticularly evident for thefirstL&Dgoal: identifying the risks and raisingawareness heavily relies on the underlying science and the socio-economic scenarios and cli- mateandimpactsmodelsused.Atop-downorscience-drivenapproachappearsmost relevant for this, but the adaptation andmitigation pathways are somewhat locked by theclimate scenariochosen. However,planninganypoliciesandmeasures inresponsewill require fromdeci- sionmakers the need to designflexible adaptation and riskmanagement pathways that allow for periodic adjustments as new information becomes available, and the possibility of changing to new routes when or if incremental adjustments are no longer considered sufficient according to the evidence available at the time (Halle- gatte 2009;Hulme et al. 2009; Lopez et al. 2010;Wilby andDessai 2010; Bhave et al. 2016).Moreover, the planning processwill have to consider the fact that the futuremight involve climate change events that are not predicted, combinedwith unforeseen technological and societal developments. The ‘policy-driven’ approach encourages theuseofmeasures that are low regret, reversible, build resilience into the system, incorporate safety margins, employ ‘soft’ solutions, are flexible, and delivermultipleco-benefits (Hallegatte2009;Hulmeetal.2009). In thiscontext the second L&Dgoal shows a strong parallel with climate adaptation planning: how tominimise the climate change risk to tolerable levels, andwhat are theoptions to managewhat cannot beminimised?Consequently, the challenges presentedby the needtoreduceandmanageclimatechangelossesanddamagesarenotverydifferent to theonespresentedby theneed toadapt toclimatechangeandvariability, and the toolsdescribedaboveseemadequate toaddress thesechallenges. For thethirdL&Dgoalof informingdiscussionsonfairburden-sharingandcom- pensationarrangements it is alsoclear thatbothapproachesareneeded.