CLIMATE CHANGE AND GLOBAL DAMAGES FROM TROPICAL CYCLONES Robert Mendelsohn Kerry Emanuel Shun...
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Transcript of CLIMATE CHANGE AND GLOBAL DAMAGES FROM TROPICAL CYCLONES Robert Mendelsohn Kerry Emanuel Shun...
CLIMATE CHANGE AND GLOBAL DAMAGES FROM
TROPICAL CYCLONES Robert Mendelsohn
Kerry Emanuel
Shun Chonabayashi
Laura Bakkensen
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
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
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)
Emissions Trajectory
Climate Scenario
Tropical Cyclone Behavior
Vulnerability Projection
Damage Function
Damage Estimate
Integrated Assessment Model
Tropical Cyclone GeneratorTropical 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
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)
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
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
Climate Change DamagesFrom Tropical Cyclones in 2100
Billion USD/yr/(%GWP)
CNRM ECHAM GFDL MIROC
Minimum
Pressure80.1
(0.15%)
13.9(0.03%)
78.8(0.15%)
41.6(0.08%)
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
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
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