Climate risks and adaptation in Asian coastal megacities: A synthesis

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Figure 2.2 ■ Manila Rainfall-Runoff Calibration HydrographsSource: Muto et al. (2010).Infrastructure scenarios and additionalclimate inputs into hydrological modelingSince the extent and impact of flooding in 2050 indifferent cities will depend not only on climate andweather variables but also on the infrastructureavailable in the cities to drain water and preventflooding, the hydrological models also assumedcertain infrastructure and flood protection scenariosto estimate flood occurrences. Further, the studiesalso made estimates and made assumptions regardingstorm surge and sea level rise as inputs to thehydrological modeling. These assumptions andestimates are discussed in more detail in chapter 3.Approach to AssessingDamage CostsThe main impact of climate change on the four citiesin 2050 is assumed to be in the form of increasedflooding. Flooding has direct and indirect effects.The direct impacts have to do with immediatephysical harm caused to “humans, property andthe environment” (Messner et al. 2007) and involvecosts from loss in the stock of infrastructure, tangibleassets and inventory, agricultural and environmentalgoods, and injuries and life loss. 22 The indirectimpacts of flooding are a result of a loss in the flowof goods and services to the economy (ECLAC 2003;Messner et al. 2007). 23 These costs are in terms oftraffic delays, production losses, or emergency expenditures.Some delays may be immediate, whileothers may be more medium term because of thesecondary effects of flood-related transportationbottlenecks and re-directed traffic, for example.Table 2.3 summarizes the different direct and indirectand tangible and in-tangible costs associatedwith flooding.The Bangkok and Manila case studies follow theapproach outlined above and estimate direct andindirect costs for four areas: (1) buildings, industry,and commerce; (2) transportation and relatedinfrastructure; (3) public utilities such as energyand water supply and sanitation services; and (4)people, income, and health. The HCMC study alsodiscusses the impacts of extreme events on naturalecosystems. However, the HCMC study does notprovide any detailed monetization of impacts. Themore macro approach it takes to damage cost assessmentis discussed in detail later in this chapter. The22One of most difficult of the direct costs to value is loss oflife. Manila and HCMC have both witnessed loss of livesduring major storms in the past but do not attempt to valuesuch losses from future storms.23It is important to be careful not to double count damagessince the value of the sum for flows from an asset wouldequal the value of the asset.12 | Climate Risks and Adaptation in Asian Coastal Megacities: A Synthesis Report
Table 2.3 ■ Direct and Indirect Costs from FloodingTangibleDirect Costs Repair, replacement, and cleaning costs associated with physical damage to assetsPublic infrastructureCommercial and residential buildingsInventoryVehiclesLoss of productive land and livestockCrop loss 1IndirectCostsLoss of industrial production or revenuesIncreased operational costs for commercial entitiesLost earnings or wagesTime costs from traffic disruptionsPost-flood flood proofing investments by the private sectorEmergency flood management costs to the public sectorIntangibleLoss of human lifeLoss of ecological goodsLoss of archaeological resourcesLong-term health costs from pollution or floodinjuriesPost-flood recovery inconvenience andvulnerability1Income loss from crop destruction is conventionally treated as a direct cost. If land is salinized or there is permanent inundation, then the loss in the asset value of land is the cost toinclude. Care needs to be taken to distinguish between one-time crop loss and land value losses that are of longer duration.Source: Modified from Messner et al. (2007).methods used by the Manila and Bangkok study todevelop cost estimates are discussed below. Figure2.3 summarizes the main steps taken in estimatingcosts and then estimating the net benefits frominvestments to reduce flooding.Damages to buildings, industry, commerce,and residents in Bangkok and ManilaA key impact of floods is on existing buildings.Floods are assumed to cause damage but not destroyFigure 2.3 ■ Estimating Impacts—A Flow ChartCurrent and 2050Floods (all cities)1 Area flooded2 Duration of flood3 Depth of floodbased on different climatechanges, land subsidence,and assumptionsabout flood control infrastructureImpacts in floodedareas on:1 Industry and Commerce2 Land, agriculture andecosystems3 Transportation4 Energy, water andsanitation5 Income, population,and healthbased on flood durationand depthValuation of damages(Bangkok and Manila):1 Repairs of buildings2 Losses in household assets andcommercial inventory and assets3 Transport delay and infrastructurecosts4 Revenue losses to the public sector(electricity utilities, hospitals,transportation authorities, waterand sanitation utilities)5 Wage and income lossesVulnerability assessment (HCMC)and valuation of:1 Infrastructure at risk2 People at risk3 Land at risk4 Likely GDP losses5 Ecosystems at risk (no valuation)AdaptationIdentification of adaptationstrategies (all cities)Estimation of adaptationinfrastructure costs andannualized benefits(Bangkok and Manila)Estimation of discountednet benefits (Bangkok andManila)Methodologies for Downscaling, Hydrological Mapping, and Assessing Damage Costs | 13
Page 4 and 5: © 2010 The International Bank for
Page 7 and 8: Figure 4.6 Damage Costs Associated
Page 9: AcknowledgmentsThis synthesis repor
Page 13 and 14: Executive SummaryIntroduction and R
Page 15 and 16: For each city, complex hydrometeoro
Page 17 and 18: infrastructure but a high emission
Page 19: these include strategies that focus
Page 23 and 24: policy implications have broader re
Page 25: 2Methodologies forDownscaling, Hydr
Page 28 and 29: Table 2.1 ■ Climate Change Foreca
Page 30 and 31: Return periods considered 18In this
Page 34 and 35: Figure 2.3 ■ Estimation of Damage
Page 36 and 37: sion and distribution lines, and en
Page 38 and 39: Figure 2.5 ■ Possible Relationshi
Page 40 and 41: prices and the same prices are appl
Page 43 and 44: 3Estimating Flood Impactsand Vulner
Page 45 and 46: Table 3.2 ■ Bangkok Monthly Avera
Page 47 and 48: Estimation of storm surge in the ca
Page 49 and 50: Climate Change Impact and Adaptatio
Page 51 and 52: Figure 3.5a ■ Affected Condensed
Page 53 and 54: Manila’s current climate—Tropic
Page 55 and 56: Table 3.6 ■ Manila Climate Change
Page 57 and 58: Figure 3.10 ■ Areas of High Popul
Page 59 and 60: is also a key economic and financia
Page 61 and 62: Box 3.3 ■ HCMC in 2050Future land
Page 63 and 64: original swamp land on which the ci
Page 65 and 66: from 68 percent to 71 percent; that
Page 67 and 68: Table 3.15 ■ Districts Affected b
Page 69 and 70: Table 3.16 ■ Effects of Flooding
Page 71 and 72: 4Assessing Damage Costsand Prioriti
Page 73 and 74: Table 4.2 ■ Summary of Flood and
Page 75 and 76: uilt outside the cities and are not
Page 77 and 78: ■■■■■■For the eastern p
Page 79 and 80: Table 4.6 ■ Flood Damage Costs Wi
Page 81 and 82: Table 4.8 ■ Flood Damage Costs in
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Figure 4.5 ■ Loss Exceedance Curv
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Box 4.3 ■ Increased Time Costs an
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Table 4.11 ■ Adaptation Investmen
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Marikina River areas through a dam,
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Table 4.14 ■ Present Value of the
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of reducing vulnerability of the po
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5Conclusions andPolicy Implications
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open land use is expected to be flo
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hydrometeorological data, yielding
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BibliographyAllen, M. R., and W. J.
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Reduction: Inventory and Prospect.
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a paper commissioned by JICA (Sugiy
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mercial and industrial establishmen
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ADB. The selection and prioritizati
Page 113 and 114:
AnnexCAdaptation to IncreasedFloodi
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of people and institutions to manag
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THE WORLD BANK1818 H Street, NWWash
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Climate risks and adaptation in Asian coastal megacities: A synthesis

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