2013年-世界发展银行全球_Cyclones_in_a_Changing_Climate___The_Case_of_Bangladesh_36页_26mb

Summary of "Cyclones in a Changing Climate: The Case of Bangladesh"

Core Content

This paper examines the vulnerability of coastal Bangladesh to cyclones and storm surges in the context of climate change, with a focus on potential damage and adaptation costs by 2050. It integrates climate change data, hydrodynamic models, and geographic overlays to estimate the impact of intensified cyclones and rising sea levels on infrastructure, population, and economic activity. The study aims to provide a framework for understanding and addressing the adaptation costs of extreme weather events in climate negotiations.

Main Views

• Bangladesh is highly vulnerable to cyclones and storm surges due to its low-lying geography, high population density, and inadequate coastal protection.
• Climate change is expected to exacerbate cyclone impacts through increased sea surface temperatures, sea-level rise, and intensified wind speeds.
• Storm surges are a major source of damage during cyclones, particularly when they coincide with high tides and strong winds.
• The study estimates potential damage and adaptation costs for a 10-year return period cyclone by 2050, under both baseline and climate change scenarios.
• Adaptation measures are essential to mitigate future losses, including strengthening polders, building cyclone shelters, improving early warning systems, and enhancing infrastructure resilience.

Key Information

Climate Change and Cyclone Intensity

• Climate change is projected to increase the intensity of tropical cyclones and the associated storm surges.
• A 27-cm sea-level rise and a 10% increase in wind speed by 2050 are used to approximate the effects of global warming.
• These changes are expected to increase the vulnerable area to inundation by 69% for more than 3m of depth and by 14% for 1m to 3m of depth.

Vulnerability Assessment

• Coastal Bangladesh is particularly at risk due to its geography and population density.
• The study identifies polders, coastal populations, settlements, infrastructure, and economic activity as key elements at risk.
• Under the baseline scenario, 8.06 million people are currently vulnerable to inundation depths greater than 3m. This number is projected to rise to 13.54 million by 2050, and to 22.64 million with climate change.

Population and Economic Projections

• The population of coastal Bangladesh is expected to grow by 68% by 2050 under the baseline scenario.
• With climate change, the vulnerable population could increase by an additional 67%, reaching 22.64 million.
• The GDP of Bangladesh is projected to increase significantly, from $75 billion in 2007 to $1,614 billion by 2050, with per capita GDP rising from $470 to $6,395.

Expected Damage and Loss

• The study estimates that a 10-year return period cyclone in a changing climate would cause $2.437 billion in damage and $2.123 billion in losses by 2050.
• Key sectors affected include:
  • Housing: Estimated damage of $1,947.3 million and losses of $0.8 million.
  • Education: Damage of $9.0 million and losses of $835.4 million.
  • Agriculture: Damage of $75.4 million and losses of $1,084.0 million.
  • Non-agricultural productivity: Damage of $87.9 million and losses of $52.7 million.
  • Roads: Damage of $239.5 million and losses of $150.0 million.
  • Power: Damage of $60.2 million and no loss estimate.
  • Coastal protection: Damage of $17.3 million and no loss estimate.
• Total potential damage and loss is estimated at $2.436 billion and $2.122 billion, respectively.

Human Casualties and Injuries

• In 2007, Cyclone Sidr caused 3,406 deaths and 55,282 injuries.
• Under the baseline scenario, by 2050, 4,637 additional casualties and 75,268 injuries are expected if no further adaptation measures are taken.
• These estimates are based on historical casualty and injury rates and may be conservative.

Adaptation Costs

• The estimated cost of implementing adaptation measures to reduce damage from intensified cyclones and storm surges is more than $2.4 billion.
• The annual recurrent cost for maintaining these measures is more than $50 million.
• Adaptation measures include:
  • Strengthening polders.
  • Foreshore afforestation.
  • Building additional multi-purpose cyclone shelters.
  • Developing cyclone-resistant private housing.
  • Enhancing early warning and evacuation systems.

Methodology and Limitations

• The study uses a five-step methodology to estimate damage and adaptation costs, incorporating economic development projections and geographic data.
• It uses GIS software to overlay exposure data with inundation zones and estimates the impact on infrastructure and population.
• The study acknowledges several limitations, including:
  • Exclusion of land subsidence in the core analysis due to uncertainty.
  • Limited consideration of out-migration and other indirect impacts.
  • Sensitivity analysis shows that vulnerability estimates may vary depending on the rate of sea-level rise and land subsidence.
  • The study assumes a 10-year return period cyclone and uses historical data from Cyclone Sidr as a reference.

Conclusion

• The paper provides a prototype for estimating adaptation costs in climate negotiations.
• It emphasizes the need for proactive adaptation measures to protect coastal populations and infrastructure from the increasing threat of cyclones and storm surges.
• The results highlight the economic and social implications of climate change in Bangladesh, urging policy makers to take immediate action to reduce future losses.