Coastal areas (IPCC AR4 report, existing literature) are expected to be at high risk due to climate change and sea level rise

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1 Poonam Pillai Senior Environmental Specialist Environment Department World Bank Objective: Give you a quick overview of the objective and methodology of a study that is being jointly undertaken by the WB, ADB and JICA on coastal cities and adaptation to climate change Coastal areas (IPCC AR4 report, existing literature) are expected to be at high risk due to climate change and sea level rise Low lying mega-deltas of Asia and Africa and small island states especially vulnerable While there is a growing literature on cities and climate change, limited research that systematically assesses risks and assesses damage costs at the city level. This study aims to fill this gap. 1

2 To provide options to mayors, national and municipal decision makers with respect to scale of CC related impacts, associated costs and policy measures needed to address them Analysis being carried out in 4 cities Manila (JICA, Megumi Muto), Ho Chi Minh city (ADB-Jay Roop), Kolkata (WB, Maria Sarraf) and Bangkok (WB-Jan Bojo) Synthesis report (ongoing) based on 4 city level reports look across the 4 city level studies to highlight major issues, lessons Collection of hydro-meterological data relating to past events and current situation (eg. river floods, storm surges, rainfall, land subsidence, sea level rise, etc.) Collection of socio-economic data, growth rates, population growth, sector specific information, information about existing flood protection structures, existing and planned infrastructure, etc. Focus is not just on city but broader riverbasin /floodplain 2

3 In this study, we consider 2 emissions scenarios A1F1 and B1 and using specific downscaling techniques, model changes in climate variable for the year 2050 Climate variables considered includes changes in local temperature, % change in precipitation, and SLR in each of the 4 cities for different scenarios (Univ of Tokyo/Ibaraki) SLR of.19m and.29m for B1 and A1F1 scenarios respectively used for each team; for HCMC-SLR of.24 and.26 m used respectively Predictions on storm surges also made-- based on data provided by Ibaraki University and information from past storm surges in each city Based on historical information collected and climate variables derived from downscaling analysis, we Estimate flooding in each metropolitan area in 2050 under different scenarios Consider floods with 3 different return periods a 1/10 year, 1/30 year and a 1/100 year floods Find out the probability of different types of floods occurring in 2050 Hydrological analysis gives us information about areas in the city more or less likely to be affected, populations affected by floods under different scenarios-presented in GIS maps Information about depth of floods, area affected, duration of flood is also used to undertake damage cost assessment 3

4 Assess impact on 5 sectors transportation, energy, industry and commerce, water supply and sanitation, ti and building and housing Methodology based on ECLAC approach for damage cost assessment linked with disasters Assess both direct costs (eg. physical damages to assets, infrastructure) and indirect costs (eg. loss of production, time costs from traffic disruption, etc.) Damage is not just due to CC, but also available infrastructure.. Assume 2 Infrastructure scenarios (i) Flood control infrastructure in 2050 is same as is currently the case and (ii) flood control infrastructure in 2050 is superior to current situation --Difference in the cost of damages linked with the 2 scenarios is an important output of the study Analysis of municipal capacity/identification of adaptation options Uncertainties at every stage, challenge is to account for errors and still have robust results 4

5 An estimated 180 sq kms of Bangkok and Samut Prakarn will be inundated under varying degrees and for a different number of days under A1F1 scenario in 2050 a 30% increase in flood prone area between million affected in the case of 1/30 year flood Damage costs are in the range of $440 million for a 1/10 year flood, more than $2 billion for a 1/100 year flood current flood protection plans need to be upgraded Approximately 80% of total damage costs are attributable to buildings (residential, commercial and industrial) The geographic extent of flooding in 2050 will increase by 7% (for regular floods)-3% (for extreme events that is, a 1/30 year flood) over current flooding. The number of communes effected by flooding in HCMC will increase both for regular floods and extreme events (e.g. from communes for extreme floods) In 2050, an extreme storm event will affect (62%/ 12.9 million people) Today it effects 1.7 million people /of about 26% of the population. In 2050, about 62% of the city population or about 12.9 million people are likely to be effected. Areas in which poor live are more vulnerable to flooding Climate change likely to lead to Loss in economic value of land, ranging from USD 6.69 to 22.1 billion (regular floods) and USD 0.46 to 6.68 billion (extreme floods) GDP loss ranging from USD 44.8 billion in present value terms (regular floods) and USD 0.18 billion (extreme floods). 5

6 Impact of climate change likely to effect the economic role played by all (four) cities in the regional/national economies Poor are more vulnerable to likely impacts from flooding linked with CC Important to build on existing social protection systems to develop adaptation measures specifically targeted to socially vulnerable groups Many coastal cities have long history of responding to natural disasters (e.g. dykes, early warning systems, etc.). However, climate change needs to be incorporated into existing flood protection plans/broader urban planning Need to focus not just hard protection measures, but also natural protection and absorption afforded by specific urban/local ecosystems Important to identify flood prone areas and implement land use regulations to minimize losses. 6