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Sector-wide Estimation of Economic Impacts of Climate Change Considering Variations in Exposure and Vulnerability
Represented by SSP Scenarios
Twelfth Annual Meeting of the IAMC 2019, Tsukuba, Japan
Jun’ya Takakura1, Shinichiro Fujimori2, Naota Hanasaki1Tomoko Hasegawa3, Yasushi Honda4, Toshichika Iizumi5, Chan Park6
Kiyoshi Takahashi1, Qian Zhou7 and Yasuaki Hijioka1
1 National Institute for Environmental Studies, Tsukuba, Japan2 Kyoto University, Kyoto, Japan3 Ritsumeikan University, Kusatsu, Japan4 University of Tsukuba, Tsukuba, Japan5 National Agriculture and Food Research Organization, Tsukuba, Japan6 University of Seoul, Seoul, Korea7 North China Electric Power University, Beijing, China
1
Introduction
• Risk of climate change depends on exposure and vulnerability as well as hazards.• Socioeconomic scenarios are needed for impact modeling to represent exposure and
vulnerability.• SSP have been widely used in studies in climate-change impacts. However, sector-wide
comparison and aggregation were difficult due to methodological inconsistency amongstudies.
IPCC AR5 WG2 SPM
2
Sector-wide assessment
Multi-sector impact assessments under the unified framework• same scenario sets• same climate models• same economic model• covering 9 (6 +3) sectors
Takakura et al. (2019)
3
Overview
RCP
Future climate
Hot world
2℃ target
RCP8.5RCP6.0RCP4.5RCP2.6
SSP1: SustainabilitySSP2: Middle of the roadSSP3: Regional rivalrySSP4: InequalitySSP5: Fossil-fueled development
Climate model(ISIMIP’s 5GCMs)
Crop model
Hydrology model
Health model
・・・
GHG concentration
Population, GDP, Technology level, etc.
・・・GDP loss
Crop productivity
Water resource
Mortality/Morbidity
AIM/CGEmodel
SSP
Challenge for adaptation
Chal
leng
efo
rm
itiga
tion
SSP1
SSP5
SSP2
SSP3
SSP4CO2
emiss
ion
Glob
al m
ean
tem
pera
ture
rise
Bio/physical models Economic model
4
Included sectors
Sector Rationale Published paperAgricultural productivity Climate will affect agricultural productivity. Fujimori et al. (2018)
Sustainability
UndernourishmentChanges in food prices due to agricultural productivity change will worsen food access and mortality/morbidity because of hunger.
Hasegawa et al. (2016) Climatic Change
Cooling/heating demand
Higher temperature will increase cooling demand while decrease heating demand.
Park et al. (2018)Environ. Res. Lett.
Occupational-health cost
Workers’ exposure to heat will limit the capacity of labor activity and productivity.
Takakura et al. (2017)Environ. Res. Lett.
Hydropower generation
Changes in precipitation will change the water resources that can be used for hydropower generation.
Zhou et al. (2018)Climatic Change
Thermal power generation
Changes in river flows will change the water resources that can be used cooling thermal power generation plants.
Zhou et al. (2018)Energies
Assessment of additional 3 sectors (heat-related excess mortality, fluvial flooding, and coastal inundation) were also done, but their results have not been connected with the AIM/CGE model.
5
Considered scenarios
SSPs
SSP1SSP2SSP3SSP4SSP5
RCPsRCP2.6RCP4.5RCP6.0RCP8.5
GCMsGFDL-ESM2MHadGEM2-ES
IPSL-CM5A-LRMIROC-ESM-
CHEMNorESM1-M
× ×
Socioeconomicpathways
Emissionpathways
Climatemodels
• Total of 100 (5×4×5) scenario runs for each sector• Impact of climate-change mitigation were not considered
(focusing only on the impact of climate change).• Only autonomous adaptations were considered.• Inter-sectoral interactions were not considered.
6
Modeling
7
Incorporation of SSP scenarios
Economic model
(AIM/CGE)
Bio/physicalimpact models
SSP
(1) Socioeconomic assumptions were fed into the bio/physical impact models
Climate EconomicImpact
(2) Socioeconomic assumptions were fed into the economic model
(1) (2)
8
Research framework (Agricultural productivity)
SSPscenarios
RCPscenarios
Land usemodel
AIM/CGEmodel
Generalcirculation
models
Climateconditions
Cropproductivity
GDP loss
Land use
AIM/CGEmodel
(off-line)
Cropmodel
Technology level(represented byGDP per capita)
Changes in crop yields associated with climate change are computed with the crop yield model (CYGMA).
CYGMA is a biophysical global gridded crop model that can explicitly consider
- changes in agronomic technology- management driven by economic growth- changes in the biophysical response of a
crop to environmental conditions
The grid-cell simulated yields were aggregated into regions considering land use, and input to the AIM/CGE model.
9
Research framework (Undernutrition)
SSPscenarios
RCPscenarios
Land usemodel
AIM/CGEmodel
Generalcirculation
models
Climateconditions
Cropproductivity
Incomedistribution
Foodprice
Number ofpeople at
risk of hunger
Expenditurefor medical care
Mortality
GDP loss
Morbidity
Land use
AIM/CGEmodel
(off-line)
Population andLabor stock
Cropmodel
Non-marketvalue of lives lost
Value ofstatistical life
Technology level(represented byGDP per capita)
Income level(GDP per capita)
Climate change (agricultural productivity change) will affect food prices and food access → undernourishment
Prevalence of undernutrition, mortality and morbidity were estimated based on the calculated income distribution and food price.
Associated economic loss were computed with the AIM/CGE model with consideration of changes in
- labor force- population- expenditure for healthcare.
10
Research framework (Cooling/heating demand)
SSPscenarios
RCPscenarios
AIM/CGEmodel
Generalcirculation
models
Climateconditions
Economicactivity level
GDP loss
ACpenetration rate
Cost forAC device
installation
Energydemand for
cooling/heating
Populationdistribution
Technology andpro-environmental
mind level
Income level(GDP per capita)
Climate change will increase cooling demand and decrease heating demand.
We considered both the cost of cooling/heating energy use and the cost of cooling/heating device installation and management.
Energy demand for cooling/heating was calculated as a function of cooling/heating degree days, socioeconomic conditions, and economic activity level
11
Research framework (Occupational-health cost)
SSPscenarios
RCPscenarios
AIM/CGEmodel
Generalcirculation
models
Climateconditions
GDP loss
ACpenetration rate
Populationdistribution
Indoor laborproductivity
Outdoor laborproductivity
Income level(GDP per capita)
Workers’ exposure to heat can cause economic loss by reduction of the per-hour workable time (labor capacity).
The labor capacity was calculated from the estimated heat stress index (WBGT) and used as the labor productivity coefficient in the AIM/CGE model.
Different assumptions were used for the different industrial sectors and socioeconomic conditions
- work location (indoor or outdoor)- intensity of work- availability of air conditioners
12
Research framework (Hydropower generation)
SSPscenarios
RCPscenarios
AIM/CGEmodel
Generalcirculation
models
Climateconditions
GDP loss
Waterdemands
AIM/CGEmodel
(off-line)
Hydrologicalmodel
Upper boundaryof hydroelectric
genera�on capacity
Theoreticalhydroelectric
generation potential
The hydroelectric power generation capacity will be affected by changes in precipitations.
The grid-based theoretical hydroelectric power potential was projected using the H08 global hydrological model.
Variations in theoretical hydroelectric power potential were assumed to lead to the hydropower generation potential variation.
13
Research framework (Thermal power generation)
SSPscenarios
RCPscenarios
AIM/CGEmodel
Generalcirculation
models
Climateconditions
GDP loss
Waterdemands
AIM/CGEmodel
(off-line)
Hydrologicalmodel
Capital productivityof thermal powergeneration sectors
Cooling watersufficiency forthermal power
genera�on
Lower river flow causes cooling water shortages leading to changes in the usable thermal power generation capacity.
We used the H08 global hydrology model to calculate the magnitude of regional usable capacity changes.
Cooling water shortage index were assumed to affect the thermal power generation potential.
14
Results
15
Overall results (sector by sector)
Agriculturalproductivity
Undernourishment
Cooling/heatingdemand
Occupational-healthcost
Hydropowergeneration
Thermal powergeneration
GD
P lo
ss ra
te co
mpa
red
to n
o-cl
imat
e-ch
ange
cond
ition
(%)
SSP1 SSP2 SSP3 SSP4 SSP5
• Great divergences in the simulated economic impact among sectors both- magnitudes- how sensitive to
socioeconomic conditions
• Larger impacts are expected under SSP3.
• Relatively smaller impacts are expected under SSP1 or SSP5.
period:2080-2099
16
Aggregated economic impacts (global)
• Aggregated economic impact equivalent to- 6.6% (3.9–8.6%) of the global total GDP @ SSP3-RCP8.5- 0.8% (0.5–1.2%) @ SSP1-RCP2.6 and 0.8% (0.4–1.2%) @ SSP2-RCP2.6
• In global scale, modification of the impacts by the variation in SSP is modest.
Takakura et al. (2019)
boxplot period:2080-2099
17
Aggregated economic impacts (regional)
• Larger impacts for developing regions such as Asia and Africa• All regions are more adversely affected under SSP3• Adverse effects are concentrated in developing regions under SSP4• While the results are consistent with the SSP storyline, socioeconomic development
alone does not cancel the impacts of climate change without the stringent mitigation.
Takakura et al. (2019)period:2080-2099
18
Unmet challenges in modeling
Adaptation• We considered only autonomous adaptation, e.g.,
- reduction of vulnerability due to increase in the income level- changes in the industrial structure- economy’s response to the shock through the market mechanisms represented by the AIM/CGE model.
• Non-autonomous adaptation is difficult to model and is not considered.
Interaction• We ran the model sector by sector.
- possible interactions among sectors were not incorporated.• Incorporating multi-sector ‘shocks’ into the CGE model simultaneously is possible,
but it will induce greater uncertainty in the results and it will be harder to interpret and validate.
19
Concluding remarks
• We have conducted impact assessments under the unified scenarios by using the same modeling framework.- sector-wide, process-based, bottom-up approach considering variations in exposure and vulnerability represented by SSP scenarios
• While the results showed modification of impacts by SSPs, socioeconomic development alone does not cancel the impacts of climate change. Climate-change mitigation and proactive adaptations are inevitable to minimize the impacts.
• If we consider proactive adaptations to climate change and their differences in difficulties to implement the adaptation measures among SSPs, the results may differ from the current one. Further model developments and analysis particularly focusing on adaptation are necessary to plan and implement effective adaptation measures.
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Asia-Pacific Integrated Modelhttp://www-iam.nies.go.jp/aim/index.html
This research was supported by the Environment Research andTechnology Development Fund (S-14) of the EnvironmentalRestoration and Conservation Agency of Japan.