Download - UNDP Climate Change Adaptation

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
Current and 2100 Baseline Impacts of
Extreme Weather Events
Current and Future Extreme
Event Damages by Region
Current and Future Deaths by
Extreme Event
Current and Future Deaths by
Region
6000
5000
4000
2010
3000
2100
2000
1000
0
Africa
Asia
Europe
Latin America
North America
Oceania
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)
Integrated Assessment Model
Emissions Trajectory
Climate Scenario
Tropical Cyclone Behavior
Vulnerability Projection
Damage Function
Damage Estimate
IPCC Emissions Scenarios
This
study
Projected Warming:
This study
Climate Models
•
•
•
•
CNRM
ECHAM
GFDL
MIROC
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
500 Synthetic Tracks Coded by
Minimum Pressure
Change in Tropical Cyclone
Power by Ocean Basin
Tropical Cyclone Damage Function
Constant Minimum Income
Pressure
Populat.
Density
US
607.5
(10.39)
0.370
(0.45)
0.488
(1.53)
Global
15.17
(22.77)
0.415
(6.44)
-0.21
(3.04)
-86.3
(9.96)
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
Current and Future Baseline
Damages by Region
30000
25000
20000
15000
10000
Current Economy
Future Economy
5000
0
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 Damages
From Tropical Cyclones in 2100
Billion USD/yr/(%GWP)
CNRM
Minimum
Pressure
ECHAM GFDL
MIROC
80.1
13.9
78.8
41.6
(0.15%)
(0.03%)
(0.15%)
(0.08%)
Climate damages by region
70000
60000
50000
40000
30000
CNRM
ECHAM
GFDL
20000
10000
0
-10000
-20000
MIROC
Climate damage as percent of
GDP by region
0.2500
0.2000
0.1500
0.1000
CNRM
ECHAM
GFDL
0.0500
0.0000
-0.0500
MIROC
Climate change increases
frequency of high damage storms
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