2010年-世界发展银行全球_Vulnerability_of_Bangladesh_to_Cyclones_in_a_Changing_Climate___Potential_Damages_and_Adaptation_Cost_54页_4mb

Summary of "Vulnerability of Bangladesh to Cyclones in a Changing Climate"

Core Content

This paper investigates the vulnerability of Bangladesh to cyclones and storm surges in the context of climate change, focusing on potential damages and adaptation costs by 2050. It integrates climate change projections, hydrodynamic models, and geographic data to assess the impact of rising sea levels and intensified wind speeds on coastal regions. The study emphasizes the need for improved adaptation strategies to mitigate the risks posed by climate change.

Main Views

• Climate Change Impact: Increased sea surface temperatures are expected to intensify cyclone activity and raise storm surge levels, increasing the vulnerability of coastal areas.
• Storm Surge Vulnerability: By 2050, a 27 cm sea level rise and a 10% increase in wind speed could lead to a 69% increase in the vulnerable zone with more than 3m inundation depth and a 14% increase with more than 1m inundation depth.
• Current Adaptation Measures: Bangladesh currently has 123 polders, over 2,400 emergency shelters, and an early warning system. However, these may not be sufficient under future climate conditions.
• Adaptation Needs: Additional measures such as strengthening polders, building more cyclone shelters, afforestation, and improving disaster response systems are required. These would cost over $2.4 billion, with annual recurrent costs exceeding $50 million.
• Population Vulnerability: Current estimates suggest that 8.06 million coastal inhabitants are vulnerable to storm surge inundation of more than 1m. This number is expected to increase by 68% without climate change and by 110% with climate change by 2050.
• Economic Impact: The study provides detailed economic damage estimates for various sectors, including housing, education, agriculture, non-agricultural productive sectors, and infrastructure.

Key Information

1. Vulnerable Zones and Inundation Depths

• A 27 cm sea level rise and 10% increased wind speed would expand the vulnerable zone by 69% for 3m inundation depth and by 14% for 1m inundation depth.
• The area affected by a 10-year return period cyclone is expected to grow significantly due to climate change.

2. Population and Assets at Risk

• Population: 8.06 million coastal residents are currently vulnerable to 1m inundation depth, and this number is projected to increase to 5.34 million and 10.04 million by 2050 without and with climate change respectively.
• Assets: Critical assets such as housing, education infrastructure, agriculture, and infrastructure (roads, power, coastal protection) are at risk of damage due to storm surges.

3. Sector-Specific Damages

• Housing:
  • "Semi-pucka", "kacha", and "jhupris" houses are most vulnerable.
  • Estimated damages from a 10-year return period cyclone in a changing climate: $1.718 million for household content and $229 million for re-plastering.
• Education:
  • 456,690 primary school students and 312,957 secondary school students are expected to be affected.
  • Estimated damage to schools: $8.96 million.
• Agriculture:
  • Cereal production (Aman, Aus, Boro) is expected to face significant damage.
  • Estimated additional damage: $788.83 million.
• Livestock and Fishery:
  • Damage to livestock: $55.62 million.
  • Damage to fishery: $66.36 million.
• Non-Agricultural Sectors:
  • Estimated damage: $87.9 million.
• Infrastructure:
  • Roads: 3,998 km are expected to be partially damaged and 8,972 km fully damaged under current conditions.
  • With climate change, these numbers increase to 10,466 km and 10,553 km respectively.
  • Additional road damage: 3,461 km partially damaged and 2,205 km fully damaged.

4. Economic Damage and Adaptation Costs

• Estimated Economic Damage:
  • From increased fatality risk: $1.03 billion.
  • From increased injury risk: $0.352 million.
  • Total estimated potential damage: $1.084 billion.
• Adaptation Costs:
  • Total investment required for adaptation measures: over $2.4 billion.
  • Annual recurrent cost: over $50 million.

5. Methodology

• A 5-step methodology was used to estimate potential damage and adaptation costs:
  1. Demarcation of vulnerable zones and projection of inundation depth.
  2. Identification of critical impact elements.
  3. Computation of potential damage for a 10-year return period cyclone.
  4. Identification of existing and required adaptation measures.
  5. Costing of adaptation measures.

6. Limitations

• The study does not address salinity intrusion or out-migration due to sea level rise.
• It does not attempt to estimate the probability of 10-year return period cyclones at specific locations.

Conclusion

The study concludes that while the cost of adaptation is significant, it is relatively small compared to the potential damage from unmitigated climate change impacts. It underscores the importance of investing in resilience measures to protect coastal populations and infrastructure from future cyclone-related risks.