Climate risks and adaptation in Asian coastal megacities: A synthesis

Figure 4.5 ■ Loss Exceedance Curvesfor Manila (PHP)Damage costs120,000,000,000100,000,000,00080,000,000,00060,000,000,00040,000,000,00020,000,000,00000.00 0.02 0.04 0.06 0.08 0.10 0.12Probability of floodsSQ EX SQ MP B1 EX B1 MP A1FI EX A1FI MPSource: Based on estimations in Muto et al. (2010).as the probability of their occurrence decreases. Aspreviously discussed, the area beneath each curverepresents the average total annual expected damagecosts from floods of all intensities (also see adaptationsection). Note that the loss exceedance curve ishighest for the A1FI emissions scenario (A1FI-EX).Climate change increases the extent of damages inall types of floods.Implementing existing Master Plansrelated to infrastructure development willsignificantly reduce flooding related costsFigure 4.6 ■ Damage Costs Associatedwith Different Scenarios(PHP)120,000,000,000100,000,000,00080,000,000,00060,000,000,00040,000,000,00020,000,000,0000SQ EX SQ MP B1 EX B1 MP A1FI EX A1FI MP1/10 1/30 1/100Source: Based on estimations in Muto et al. (2010).As Figure 4.6 shows, under each climate scenario,implementing the master plan will result in a significantreduction in costs. In an A1FI climate changescenario, for example, a 1-in-30-year flood will resultin damages to the extent of PHP 69 billion ($1.5 billion)without the master plan and PHP 19 billion($427 million) with the master plan implemented, soimplementing the master plan would reduce flooddamages by over 70 percent, given climate changeand the possibility of a 1-in-30-year flood. Thus, avery good starting point for Manila, in terms of itsresponse to climate change, would be to reconsiderand evaluate the master plans that are already onthe books.Building damages make up a major portionof flood-induced costsThe single most important contributor to totaldamage costs in each of the climate scenarios isdamage to buildings. Approximately 72 percent ofthe costs from a 1-in-30-year flood (averaged acrossall scenarios), for instance, result from damage tobuildings. Figure 4.7 shows the damage to buildingsin the case of a 1-in-30-year flood. The damagesare significant. Implementing the master planwill reduce damages significantly. In the case of a1-in-30-year flood with an A1FI emissions scenario,implementing the master plan will reduce damagesto buildings by 74 percent (relative to A1FI-EX).Income losses from climate changeassociated floods will increase by 9 to 16percentFloods will result in income or revenue losses toindividuals and firms. A 1-in-30-year flood withFigure 4.7 ■ Damages to Buildingsfrom a 1-in-30-year Flood(2008 PHP)60,000,000,00050,000,000,00040,000,000,00030,000,000,00020,000,000,00010,000,000,0000P30SQ EXP30SQ MPP30B1 EXSource: Based on estimations in Muto et al. (2010).P30B1 MPDamages to BuildingsP30A1FI EXP30A1FI MPAssessing Damage Costs and Prioritizing Adaptation Options | 63