Global Model Studies in AIM

Kiyoshi Takahashi
The 28th AIM workshop @ NIES [Online]
14 September 2022

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Global analyses of decarbonization and sustainable development[2021‐2025]

Detailed descriptionof natural system‐ Interaction between the systems‐ Tipping; Planetary boundaries

2020

2030

2040

2050

2060

(3) Long‐term analyses of earth‐humansystem sustainability
・ESM‐IAM linked model・Interaction among climate, carbon cycle and humanactivity
・Further understanding of tipping elements
2070

2080

2090

2100

…

(2) Long‐term mitigation and SD
・Extended CGE model for SD indicators analyses・GHG pathways towards the achievement of PA‐ Long‐term socio‐economic scenario ・Analyses of knock‐on effects of mitigation on SD‐ Emission pathways toward the long‐ ・Climate risks under the GHG pathways and their implication to equality
term climate target‐ Assumed availability of BECCS etc.

(1) Near‐/Mid‐ term mitigation and SD‐ Spatial socio‐economic scenarios‐ Model modules of CGE/IAM

・Mitigation analyses based on the end‐use models
・GHG pathways for 2030‐ 2050 towards the 2050 target
・Effects of climate policy on SD issues such as air pollution
and natural resource management
・Evaluation of NDCs achievements under the PA‐ Political/technical constraints for theDetailed descriptionof human system

near‐term period‐ International process of stocktaking2

On‐going projects on the AIM global model• Funded by Ministry of Environment• 2‐2002: Global analyses of climate mitigation for achieving net‐zeroemissions and sustainable development (Takahashi)• 1‐2101: A Study on global decarbonization pathways considering
technological, economic and social feasibility (Fujimori)• S‐20‐3: Research on mitigation to climate change andenvironmental impacts caused by short‐lived climate forcers(Hanaoka as a theme leader)• SII‐6‐2: Development of global scenario model for effectivenessevaluation of the Minamata Convention on Mercury (Hanaoka as aproject member)• In‐kind contribution to internationally coordinated activity• ENGAGE: EU horizon 2020 project ended at 2022 Sep. National andglobal studies and SDGs.
• ELEVATE: New EU horizon project started at 2022 Sep. More focus
on national circumstances.
• AgMIP: agricultural model intercomparison moving to 4th phase3

Recent major topics of the AIM’s global model study• Integrated analyses of climate impacts• Economic loss caused by climate impacts (Takakura et al., 2019)• Development of climate impacts emulator (Takakura et al., 2021)• Food security (hunger risk and malnutrition) caused by crop yield change and mitigation
policies• Impacts of climate policies on food intake and hunger risk (Hasegawa et al., 2018; Fujimori et al., 2022)• Impact of change in extreme climate on hunger risk (Hasegawa et al., 2021)• Nutritious implication of dietary change from meat to fish (Xia et al. , in prep)• Interrelationship between climate change and biodiversity• Impacts of climate change and climate policy (land‐use change) on biodiversity (Ohashi et al., 2019 ;Hirata et al., in prep)• Impact of ecosystem conservation on potential renewable energy (Wu et al., 2019; Nyairo et al., 2022)• Wildfire, air pollution, linkage with ESM• Climate impacts on wildfire and its implication on human health (Park et al., 2021; Park et al., in prep.)• Operational application of GEOSChem and linkage with other models (Jansakoo et al, in prep.)• Social issues• Climate policies and income distribution using AIM/PHI (Fujimori et al., 2021)• Climate and SDGs

• Side effects of climate policies on the SDGs indicators (Fujimori et al, 2020; Liu et al., 2021; Zhao et al.,2022)• Global energy technology models• Global mitigation analyses considering new technologies (hydrogen, ammonia, synfuel) using
AIM/Technology (Oshiro and Fujimori, 2022)• Global mitigation analyses using AIM/Enduse[Global] (‐> Dr. Hanaoka’s talk on SLCFs andDecarbonization in Asia; Hanaoka et al., under review)

4Decomposition analyses of impacts of climate policies
on food security (AgMIP output)
Using six global agroeconomic models, we showed the extent to which three factors—non‐CO2emissions reduction, bioenergy production and afforestation—may change food security andagricultural market conditions under 2 °C climate‐stabilization scenarios.
Results showed that afforestation (often simulated in the models by imposing carbon prices onland carbon stocks) could have a large impact on food security relative to non‐CO2 emissions
policies (generally implemented as emissions taxes).

Fujimori, Wu and et al. (2022) Nature Food5

Socio‐economic trajectories, urban area expansion and ecosystemconservation affect global potential supply of bioenergy
Risper et al. (2022) Biomass and Bioenergy• Highlights• A sustainable socio‐economic pathway yields the highest bioenergy potential.
• Urbanization impact insignificant at global but more pronounced at regional level.
• By shrinking land area, ecosystem conservation severely impacts bioenergy potential.6

Air pollution study new possibility
Operational application of GEOSChem and linkage with other models

Health and yield changes•
Comparison with observation bymonitoring stations•

Many more interesting topics would be raised where we cantake an advantage of being operated by a global IAM teamInteraction with climate and air pollution

Jansakoo et al. (in prep)Climate and Socioeconomic Impact on Fire PM2.5 Mortality
Health and wellbeing
land use change forcropland (food) on
deforestation fires

About 100,000 people are died due to fire driven PM2.5.
Fire-PM2.5 mortality has severe inequality by country
because fire contribution is higher in Africa and equatorialAsia.

Carbon cycle in soilvegetationatmosphere

Cropland (food)Climate change

Land use change

Biomass, aridity

Deforestation fires

Forests, peat fires

GHG emissions

Water, soil quality

Aerosol emissions

PM2.5

Life in land, water,and sanitation

Health and wellbeing(%)(Martin et al., 2019)

Park et al. (in prep)

Country‐wise poverty gap and carbon tax
comparison (bil. $)17 regions AIM/Hub classification  change ratio is taken
HouseholdPrice changes byincomegoods
loss

AIM/PHI

190 countries
Incomemodule•Log‐normal distribution
Household consumption percap, population, and Gini
coefficientConsiders macroeconomic
income losses

Actual expenditure
by incomesegments••

AIDADS function is assumed•
Extension of (generalized) LES or CDE
function
Individual segment’s consumption (every10$ for poor) is computed for 12 household
consumption categories
100%80%
Budget share••

Povertyindicators

Expenditure
moduleIncome distribution
within countries

Carbon tax
revenue60%•

Carbon tax is much larger than poverty gap•

Small potion of carbon tax via International transfer
might help poverty eradication

40%
20%
0%
800900

1000
2000
3000
Annual income per capita ($/cap)

Miscellaneous goods and services
Education
Communication
Health
Housing, water, electricity, gas and other fuels
Alcoholic beverages, tobacco, and narcotics

40005000

Restaurants and hotels
Recreation and culture
Transport
Furnishings, household equipment and maintenance
Clothing and footwear
Food and nonalcoholic beverages

Fujimori et al. (2020) Environ. Resear. Lett.

Another example of synergy/tradeoff analysis‐ CO2 vs Hg ‐a)

Low‐carbon scenario(toward 2℃ target)b) Carbon‐neutrality scenario(toward 1.5℃ target)

Figures are deleted for avoiding copyright issues.

Hanaoka, T., Nakajima, K., … ..Takaoka, M. (Under review) Resources, Conservation and RecyclingEnergy system model [AIM/Technology]

GHG•
•
•

CO2 reduction and hydrogen‐based energy (inc. synfuel)Hourly resolution in power demand‐supply
New technologies (hydrogen, ammonia,synfuel)More advancement will come out!!
Oshiro and Fujimori (2022) Applied Energy

Intended outcomes of the global study in AIM• Provision of objective evidences and views on long‐termtargets and policies at global scale (to policymakers as wellas to public citizens)• Communication of uncertainties• Provision of boundary conditions for regional/national /local
policy analyses• Improved comprehensive understanding of global risks andproposition of potential strategies for managing them.
• Linking multiple disciplines for not overlooking importantinterrelations and feedback effects• Contribution to science via publications, especially assessedby IPCC• International model intercomparison projects for methodologicalsophistication and frontier progress• Maintenance of research infrastructure such as the development ofSSPs

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Last year’s AIM national activity outcome
 IAMC level community activity (SWGs on national scenarios)

Good news: Prof. Fujimori was awarded the IAMC Award forExtraordinary Contributions to the field of IAM in 2021

Global model study in AIM‐ Missing elements / Research gaps ‐• Improved consideration of social aspects• Economic growth and development• Inequality• Conflicts and migration• More comprehensive analyses of human health• Further integration with biodiversity studies• More consistency between spatial scales• Contribution to the integration phase of the SSP‐RCPframework• Unconsidered feedbacks between climate policies, climate impacts
and development

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