CLIMATE CHANGE AND GLOBAL DAMAGES FROM TROPICAL CYCLONES

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CLIMATE CHANGE AND GLOBAL DAMAGES FROM TROPICAL
CYCLONES

• Robert Mendelsohn
• Kerry Emanuel
• Shun Chonabayashi
• Laura Bakkensen

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Acknowledgements

• Funding by World Bank-United Nations Global
  Facility for Disaster Reduction Recovery
• Report
• Natural Hazards, UnNatural Disasters The
  Economics of Effective Prevention
• Apurva Sanghi

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Goal of this Study

• Predict how climate change will affect tropical
  cyclones
• Reflect underlying changes in vulnerability in
  future periods
• Estimate damage functions for tropical cyclones
• Measure how climate change affects future
  tropical cyclone damages

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Current and 2100 Baseline Impacts of Extreme
Weather Events
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Current and Future Extreme Event Damages by
Region
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Current and Future Deaths by Extreme Event
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Current and Future Deaths by Region
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Past Climate Results

• IPCC 1996 estimates CC increases US tropical
  cyclone damages by about 0.02 of GDP and world
  damages by 0.002 of GWP
• Nordhaus 2010 estimates CC doubles US tropical
  cyclone damages (0.06 of GDP)
• Narita et al 2007 estimate CC doubles world
  tropical cyclone damages (0.006 GWP)

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Integrated Assessment Model
Emissions Trajectory
Climate Scenario
Tropical Cyclone Behavior
Vulnerability Projection
Damage Function
Damage Estimate
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IPCC Emissions Scenarios
This study
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Projected Warming
This study
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Climate Models

• CNRM
• ECHAM
• GFDL
• MIROC

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Tropical Cyclone Generator

• Step 1 Seed each ocean basin with a very large
  number of weak, randomly located cyclones
• Step 2 Cyclones are assumed to move with the
  large scale atmospheric flow in which they are
  embedded, taken from the global climate model
• Step 3 Run a detailed cyclone intensity model
  for each event, and note how many achieve at
  least tropical storm strength
• Step 4 Using the small fraction of surviving
  events, determine storm statistics.

Details Emanuel et al., Bull. Amer. Meteor.
Soc., 2008
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500 Synthetic Tracks Coded by Minimum Pressure
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Change in Tropical Cyclone Power by Ocean Basin
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Tropical Cyclone Damage Function
Constant Minimum Pressure Income Populat. Density
US 607.5 (10.39) -86.3 (9.96) 0.370 (0.45) 0.488 (1.53)
Global 15.17 (22.77) 0.415 (6.44) -0.21 (3.04)
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Baseline Tropical Cyclone Damages

• Current Global Damages 20 billion/yr (0.03
  GWP)
• Future Baseline Damages 55 billion/yr (0.01
  GWP)
• Baseline increases by 2100 because of higher
  income but not as much as GWP
• Baseline assumes current climate

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Current and Future Baseline Damages by Region
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Estimate Climate Impacts

• Calculate future baseline damages (current
  climate)
• Calculate future damages with future climate
• Subtract baseline from future damages with future
  climate to get net climate impact

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Climate Change DamagesFrom Tropical Cyclones in
2100 Billion USD/yr/(GWP)
CNRM ECHAM GFDL MIROC
Minimum Pressure 80.1 (0.15) 13.9 (0.03) 78.8 (0.15) 41.6 (0.08)
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Climate damages by region
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Climate damage as percent of GDP by region
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Climate change increases frequency of high damage
storms
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Limitations

• All steps of the integrated assessment are
  uncertain
• Possible interaction with sea level rise not yet
  taken into account
• Current analysis at national level- needs finer
  spatial resolution
• No explicit adaptation

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Conclusions-1

• Damages from tropical cyclones almost triple by
  2100 from income growth
• Climate change likely to double these damages
• Largest CC impacts felt in US and then China
• Island nations will have largest CC impacts as a
  fraction of GDP

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Conclusions-2

• Damages concentrated in large infrequent storms-
  10 worst storms will cause 93 of total damages
  with CC
• Protect against high winds with coastal building
  codes
• Hard structures (sea walls) are ineffective
  protection against infrequent storm surge
• Restricted land use at low points along
  vulnerable coast

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