Compound Risks
of Climate Change:
Implications to Japanese
economy and society
National Institute for Environmental Studies

The aim of this report is to publicize the research activities and key outcomes of the research project, “Study onsocioeconomic risks to Japan caused by global climate change impacts”, funded by the Environmental Restoration
and Conservation Agency（ERCA）（JPMEERF20182001）（duration period April 2018 to March 2021）, withsupport of the Ministry of the Environment, Japan.
Please contact each sub-theme project leader for more information.
Project leader: Dr. Yasuko Kameyama, National Institute for Environmental Studies（NIES）
Sub-theme and theme leaders（１）Analysis of information concerning climate change impacts outside Japan and related risks
Yasuko Kameyama, National Institute for Environmental Studies（NIES）（２）The effect of overseas impacts of climate change on Japan’s economic activities via the international supply
chain
Keisuke Nansai, National Institute for Environmental Studies（NIES）（３）The effects of changes in food production due to climate change impacts on food imports in JapanGen Sakurai, National Agriculture and Food Research Organization（４）Climate fragility risk in Asia
Kentaro Tamura, Institute for Global Environmental Strategies（IGES）（５）Theoretical aspects of climate change and security concepts
Seiichiro Hasui, Ibaraki University（６）Measures to address climate change risk in international systems
Yukari Takamura, University of Tokyo

Summary
The increasing frequency of heavy rainfalls and severe typhoons is said to be caused by the adverse effects of climate change.
Among various climate change risks, physical damages by natural disasters in Japan are increasingly being acknowledged by
the public and have been investigated in many studies. However, studies from overseas have pointed out that climate change
impacts in various parts of the world can increase economic and sociopolitical risks through various routes. Climate change
impacts therefore need to be recognized as a compound risk that includes diverse domestic and international impacts. To date,
this approach has not yet been taken in Japan.
This aim of this research project is to deepen our knowledge from the perspective of each of the six types of climate risks
shown in Figure. Until now, these risks have merely been discussed in Japan, even though they are particularly important fornational risk management. As shown in the figure, these risks are not only components of the compound risk for Japan, but eachtype of risk can also contribute to the others. The research for this project is ongoing, but the findings and results obtained at
this stage are as follows.
(1) C orporate activities are affected by climate change through various routes. In general, companies have a greaterawareness of the effects of short-term risks such as torrential rains and floods, but they are not necessarily be aware ofrisks resulting from high temperatures or slow-onset events that appear gradually over time.
(2) We are developing an international trade model that represents the import and export of 5041 products. We can now
reproduce past performance values, and we plan to use the model to show the relationship between past disasters andchanges in quantity of trade. It is expected that an increase in the number or severity of disasters in a region will affecttrade between that region and Japan.
(3) Because of the effects of drought and high temperatures, it is expected that world food production will decline if nocountermeasures are taken in the future. The world population is expected to continue increasing, so Japan, which
imports a large amount of food, needs to consider the regions from which food (especially grain) is procured as well as its
food supply methods.
(4) Targeting Asian countries that have strong ties with Japan, we independently developed a climate vulnerability index
based on multiple indicators. This index can be used to show the vulnerability of countries to climate change impacts andtheir reliance on emergency humanitarian assistance from abroad, including from Japan.
(5) The concept of climate security is related to other types of security concepts. Although studies have clarified the strong
links between food and energy security and climate security, climate mitigation actions are likely to have positive effects
in other areas of security, such as maritime and human security.
(6) Island countries such as Japan are affected by sea level rise, which could lead to Japan’s territory, territorial waters, andExclusive Economic Zone shrinking in the long run. In addition, the number of refugees overseas is increasing as a resultof climate change, and there is a growing demand for a response in the international community. It is important for theJapanese stakeholders to start discussing these issues.
Figure. The six climate change risks assessed in this research project－5－

What is the compound climate risk toJapan?
―About the project―
The frequency of extreme weather events such as heavy rainfall and intense summer heat has been increasing globally in recent
years, and climate change is said to be the cause. Japan has experienced severe rainfall and typhoons that have led to the lossof hundreds of lives and thousands of dwellings. However, risks associated with climate change impacts are not limited to thoseexperienced in Japan. For example, in 2011, extreme rainfall in Thailand flooded many factories along rivers. As a result, many
automobile and computer-related industries in developed countries had to stop their production lines for several months because
they could not procure parts from those flooded factories. Sea level rise has displaced people living in the Pacific island nations,and migration to Australia and New Zealand is already on the rise. Agricultural products such as coffee and vanilla beans aregoing to grow in different areas from today’s cultivation areas if global warming continues. Many studies suggest drought related
to climate change will worsen food shortages and cause conflicts in Africa and the Middle East. These examples indicate thatclimate change impacts outside Japan could pose risks to Japan in many ways, both directly and indirectly.
The term “compound risk” is used when various risks are related to each other in a complex manner and aggravate the total
level of risk. The term has been increasingly used to express risks arising from climate change. However, there has been little
debate in Japan over compound risk as it applies to climate change and what it could mean for Japan’s security. The aim of thisresearch project is to deepen our understanding of six types of climate risks that have not been discussed in detail in Japanbut that could have serious impacts. As mentioned previously, physical damages resulting from domestic natural disasters are,of course, one of the risks of climate change, but they are not included in this study because people are already aware of suchrisk, and many studies are already underway on this topic. The six risks addressed in this project are illustrated in the circles
in Figure 1, where blue represents economic risk and red represents sociopolitical risk. The two colors are mixed in different
ratios in each circle, with the color distribution representing the risk allocation. As the arrows in Figure 1 show, these risks are
not only components of compound climate risk, but they also work as driving forces of the other risks. The six risks and related
project activities are briefly summarized below.
Risk 1: Risk perception in the business sector. This research proceeds from the perspective of the kinds of climate change
impacts that companies recognize as risks to themselves. Companies are expected to face different types of climate changerisks according to their respective business types. What risks are common to all industries? Are there any risks that industries
are not yet aware of but that could become significant in the future? In addition, because Japanese companies import resources
and procure a large amount of goods from overseas, we consider the impacts from a regional perspective and where they are
most likely to occur.
Risk 2: Risks to the supply chain and trade. Here, we are developing a model that uses import and export data to analyze theimpact of overseas disasters on Japan's trade volume. This model could be used to explain the case in which Japanese companies
suffered economic losses, for example, as a result of the flooding in Thailand in 2011. By understanding Japan's trade structure
and its relation with climate-related disasters, it will be possible to predict which industries in Japan will be affected by extreme
weather events overseas in the future.
Risk 3: Risks of food supply disruption. We evaluate Japanese food security, particularly in terms of supply. Japan’s food selfsufficiency rate is currently less than 40% (on a calorie basis). As the frequency and severity of abnormal weather increase
globally, the international prices of wheat and other staples will fluctuate. In the future, as the world population continues togrow and food demand increases, how will global fluctuations in food supply affect Japan's food imports? To answer this question,
we must be able to estimate future changes in the production of major grains in each region of the world. In addition, we alsoneed to take into account how much people will be able to respond to changing climate conditions through breed improvement,
irrigation, and other adaptation measures. We plan on generating estimates of future production under various scenarios.
Risk 4: Social instability in Asia. Japan is located in Asia, and therefore, stability in Asia is important for Japan’s security. Japan

Project representative
Yasuko Kameyama (National Institute for Environmental Studies (NIES))－6－

supports developing countries through its Official Development Assistance, but recent increases in extreme weather patterns
have made it necessary to construct bridges and roads in these countries with more severe climate-related assumptions.
Furthermore, in these countries, post-disaster social instability (e.g., riots and looting) could lead to deteriorating security,
posing a greater sociopolitical risk. Therefore, we are aiming to develop an index that measures the vulnerability of Asian
countries to climate change from various perspectives and to use the index as criteria for determining whether or not assistancefrom other countries is needed. We will also engage with experts from several countries and develop suggestions for what we
can do to reduce vulnerability in developing countries.
Risk 5: Climate security in the Asia-Pacific region. Our goal in studying this risk is to extend the concept of climate security,
which has been studied mostly in Europe and the United States for more than 20 years, to the Asia-Pacific region. Although“climate security” is an unfamiliar notion in Japan, studies have been and continue to be conducted on how environmental
destruction/deterioration causes water and food shortages and thereby increases conflicts among neighboring people. This
causal relationship indicates that efforts to protect the environment will also help to avoid human conflict. The idea that climatechange will impair the materials and social stability necessary for humans to live in dignity is also part of the concept of “climate
security”, but in Japan, this is generally included as part of the concept of “human security”. We reorganize these concepts andideas, and apply them to Japan and the Asia-Pacific region.
Risk 6: Risks related to Japanese territory. For this risk, we examine the impact of climate change on conventional national
security. First, displacement of people has been on the agenda at United Nations Framework Convention on Climate Change(UNFCCC) meetings in recent years. As more people migrate from areas that become uninhabitable due to natural disasters
and rising sea levels, a system to support these people is urgently required. This issue has begun to be discussed at the
UN Office of the High Commissioner for Refugees and the UN Security Council, and collaboration between internationalorganizations will be required to find solutions. From another perspective, Japan's Exclusive Economic Zone is predicted toshrink as a result of sea level rise, which poses another national security risk. Although these issues have not been addressed inJapan, it may be pressured to respond to these and similar issues in the near future.
In the next sections, we explain our research progress on these risks and the related six sub-themes to date. Based on theseachievements, we expect that discussions of these important issues will be advanced in Japan to prepare to meet the challenges
posed by climate change risk.
Figure 1. The six climate change risks assessed in this research projectNote: The arrows indicate relationships between risks. Blue represents
economic risk and red represents sociopolitical risk. The color distribution
represents the risk allocation for each risk.

－7－Risk perception in the business sector
Sub-theme 1: A nalysis of information concerning climatechange impacts outside Japan and related risks
Background
Climate change affects individuals and organizations in various ways, and companies are no exception. At the request of theG20 Finance Ministers and Central Bank Governors Meeting, the Financial Stability Board established the Task Force on
Climate-related Financial Disclosure (TCFD) in 2015 to help the financial sector address climate-related issues. In order forinvestors to make decisions on investments in companies, the TCFD requires companies to disclose climate-related informationin addition to conventional financial information. Climate-related risks can be broadly divided into two types: “transition risks”
are those risks caused by greenhouse gas (GHG) emission reduction (mitigation) policies, and “physical risks” are those that arecaused by climate change impacts, such as extreme weather. In questionnaire surveys administered to companies by the World
Economic Forum every year, the greatest number of companies have responded that the biggest risk to corporate management
has been the climate in recent years, indicating that Table 1. Types of climate risks to private companies
corporate executives perceive that their activities
Impact inside country
Impact outside country
and climate change are closely related.
I n this way, compa nies a re in an era where
investors are required to judge and prepare forclimate-related risks to themselves. However, it
is difficult to accurately determine what impact
climate change will have and the extent of those
impacts.

Transition risks

Physical risks

Impact of domestic mitigation
policies such as a carbon tax.

Impact of mitigation policies
outside country, including
criticism against use of coal
power plants

Impact in country such as
extreme rainfall

Impact outside country thatindirectly affect activities
inside country such as by
trade

Table 2. Risks to Japanese companies arising from physical risks
Type of risk

Possible risks to Japanese companies

Short-term increase in
rainfall that could result infloods








Floods, typhoons, etc., causing damage to buildings and facilities
Shut-down of transportation systems and logistics
Workers not able to come to work due to damages in transportation system
Delay in delivery of products due to supply chain shut down
Extension of construction period for buildings and infrastructure
Damages to agricultural products

Long-term sea level riseand high tide

Loss of land and facilities near sea shore
Damages to facilities near shore due to short-term high tide
Delay in ship transportation due to inability to use ports

Water shortageDecrease in water use in factories, leading to decrease in production
Decrease in crop yield due to water shortage
Forest fire due to extraordinarily dry climate

Heat stress








 ecrease in labor force productivity due to heatstroke
D
Increase in use of electricity for air conditioning during summer
Loss of productivity in agricultural sector; shift of suitable climate for agricultural products
Delay in delivery of products due to melting of road asphalt
Shift in fishery areas due to warmer sea water
Change in final consumers’ preferences (can also be opportunities)

Others, including
investment and reputation
risks





Increase in costs due to increase of risks of new investments
Increase in insurance fees
Price increases caused by speculation in addition to price increases caused by the above-mentioned risks

Project members
Yasuko Kameyama, Kiyoshi Takahashi, Yasuaki Hijioka, Masashi Okada (National Institute for Environmental Studies (NIES))－8－

Research outline
To understand the perception of Japanese companies regarding climate-related risks, we conducted a series of interview
surveys. Climate change risks to companies can generally be divided into four types, as shown in Table 1, but the target of thisproject is the risk caused by climate change impacts outside Japan, so the lower right frame in Table 1 is the specific target. The
risks faced by companies were comprehensively extracted from academic journals and reports on physical climate impacts, andthey are summarized in Table 2. We asked representatives of Japanese companies about their perceptions of the risks describedin this table. Our aim was to have as much diversity in industry type as possible in the survey group, and 11 companies agreed
to participate.
Regarding inundation caused by short-term increases in precipitation, we found that most of the companies had experienced
some economic losses during the 2011 flooding in Thailand. Specific damages reported included damages to buildings causedby flooding, breakdowns in electrical systems, property damage to products and materials stored in the buildings, productdelivery delays because of disruption of the transportation network, costs incurred by paying wages to employees who could
not commute for several months, support for other companies that suffered damage, additional labor costs allocated to confirm
damage, and production delays resulting from the late arrival of some parts in the manufacturing process in Japan. Theinterviewees reported being better prepared for any similar future problems.
There were no reported cases where drought itself caused damage. However, there were several cases where the interviewees
expressed concern. In particular, companies operating in South America, India, Thailand, Singapore, Australia, and Turkey or
who imported goods from these areas expressed concern about drought. There was one case where a local worker who operated
a factory in Latin America proposed that the company install a rainwater tank, under the assumption that there could be a riskof a water shortage at some point in the future.
Heat stress generally appeared to be of less concern to the interviewees as compared to other types of climate-related impacts.
They did not mention, for instance, the possibility of increased use of electricity for air conditioning of rooms where products
are stored or employees work. Additional wages also might be needed for workers who work outdoors because they may needmore time to rest in a hotter climate. In the case of companies that operated overseas, some respondents pointed out thatcompanies that are not sufficiently prepared for the effects of climate change are perceived as having higher management risks
and to face reputation risks. Japanese companies also were paying attention to reputation risk in their overseas operations, butthey did not consider Japanese consumers to be sufficiently aware of the issue to incur reputation risks in Japan.

Future plans
We found that the 11 surveyed Japanese companies were highly aware of some climate risks and preparing or considering how
to deal with them. On the other hand, there were also cases in which companies had not considered how to prepare for changes
that occur gradually rather than abruptly, such as rising sea levels and rising average temperatures.
Out next step is to increase sample size of companies to better capture general trends. We are starting to utilize data ofquestionnaire surveys conducted annually by CDP, a London-based organization. By increasing the number of companies in thesample, we will be able to clarify the characteristics of each industry type. For example, it will be possible to determine whether
there are differences in risk perception between the manufacturing industry, which imports goods from overseas, and thefinance and insurance industries. Also, given the different industrial and trade structures in the various countries, we should be
able to identify differences in awareness between Japan and other countries.

References
・K ameyama, Yasuko and Keishi Ono (2020) “The Development of Climate Security Discourse in Japan,” Sustainability Science online doi: 10.1007/
s11625-020-00863-1
・K ameyama, Yasuko (2019) Report on climate-related risks onto companies arose from climate change impacts outside Japan, NIES website, April
2019, https://www.nies.go.jp/social/jqjm1000000gjz69-att/2-1801_hearing_201904.pdf (in Japanese)－9－

Risks to the supply chain and trade
Sub-theme 2: T he effect of overseas impacts of climatechange on Japan’s economic activities via theinternational supply chain
Background
The total value of Japan's imports in 2019 was about 78.6 trillion yen. It has more than doubled from 33.9 trillion yen in 1990,
and the dependence of the Japanese economy on imported resources, materials, and products continues to grow. Against
this background, “footprint” studies have focused on the relationship between Japanese production and consumption and theinternational supply chain. They have also examined global sustainability issues and Japan's consumer responsibility. This line ofthinking has also led to the study of Japan’s carbon footprint, which indicates the amount of greenhouse gases and fine particles(PM 2.5) that are indirectly emitted in each country throughout the world through the international supply chain as a resultof Japan’s final consumption. Footprint studies also have revealed the amount of land modifications caused by metal mining
stimulated by demand from Japan. The overseas impact of the Japanese economy is remarkable worldwide, and it has beensuggested that raising awareness of consumer responsibility is essential for global sustainability.
There are also cases where the footprint concept has been applied to quantify the involvement of the Japanese economy in social
risks abroad. For precious metals, the risk undertaken by mining countries was defined by taking into account factors suchas uneven distribution of resources and political instability in the mining countries, as well as the direct and indirect risk thatJapan's final demand is implicitly exposed to through the supply chain. The results showed that mining risk was concentrated
in capital formation and export demand. The current COVID- 19 pandemic has also been observed to have had a cascading
effect on the global economy because of production constraints in each country. These facts highlight the need to establish an
economic structure that is robust against risks and to identify the risks related to production activities in countries around theworld as well as Japan's involvement in the supply chain.
The increase of natural disasters resulting from climate change is a production constraint of increasing concern. The previously
discussed damage to production facilities caused by the 2011 flood in Thailand is an excellent example of this type of production
constraint for the Japanese manufacturing industry. A worldwide increase in the frequency of natural disasters, such as floods
and droughts, will increase the vulnerability of the international supply chain on which Japan's production and consumption
depend, and will pose a significant risk to the Japanese economy. However, few studies have evaluated the impact of changes in
the frequency of natural disasters on the international supply chain, and no study has focused on Japan, which hinders the studyof Japan's ability to assess and avoid economic risk associated with climate change.

Figure 2. Example of verification of reproducibility of actual values of total trade amount by product in an international trade model (fromleft to right: natural gas and liquefied natural gas, crude oil, aluminum, and copper)

Project members
Keisuke Nansai, Kenichi Nakajima (National Institute for Environmental Studies (NIES))
Ryoko Morioka (National Agriculture and Food Research Organization (NARO)) fiscal year 2018 only

－ 10 －

Research outline
The purpose of this study is to estimate changes in the international trade structure that accompany changes in the frequencyof natural disasters, and analyze the effects on Japan's production and consumption system. To do so, we first modeledinternational trade using machine-learning methodologies. We defined international trade as a three-dimensional structure of[exporter] × [importer] × [trade commodities], and we developed a method to decompose this structure into a vector showing
trade volume and a trade structure matrix showing probability of import and export. For the international trade data, we used
BACI (International Trade Database at the Product-Level), which is an improved international trade database issued by the
UN Statistics Bureau. In this study, we compiled international trade data for each year from 1995 to 2017, with 216 exporting
countries, 216 importing countries, and 5041 products. The unit of trade volume is based on weight (tonne).
The decomposition of international trade data was performed as follows. First, we focused on each matrix defined on the threesides of the cubic data. The three aspects were (A) a table consisting of exporters and importers that showed the amount ofimports and exports between countries by item, (B) a matrix of [exporters] × [items] that shows the total export amount byitem of each country, and (C) a matrix of [importing countries] × [items] that shows the total import quantity by item of eachcountry. Aspect (A) defined 5041 matrices, and (B) and (C) defined one matrix each. Next, we decomposed each of the above
matrices into a vector corresponding to the trade volume (a vector with the row sum as an element and a vector with the column
sum as an element) and a double probability matrix corresponding to the trade probability of the matrix element. A vector(function form) was constructed by learning the elements of the vector obtained by the above decomposition (total trade amountof each item, total import amount of each country, and total export amount of each country) and the trade probability by ridge
regression. In addition to socioeconomic indicators, greenhouse gas emissions were included as explanatory variables, with theintention of taking into consideration of climate mitigation policies. Future greenhouse gas emissions and socioeconomic index
values were assigned to the obtained function form, future vector elements and trade probabilities were predicted, and eachresult was recombined to build the future three-dimensional international trade data. We confirmed the reproducibility of model
output by comparing it with actual historical values (Figure 2).
To connect international trade with Japan's production and consumption system, the 2015 version of Japan’s input-output table
and the corresponding international trade code for the 5041 products were used to make a direct and indirect classification
by sector of Japan's final demand. We constructed a database that can identify relationships with various international trade
products. In addition, we also began to develop a regional input-output table to analyze the relationship between Japan's regional
demand and trade (see references below).

Future plans
In the future, we plan to add the frequency of natural disasters to the explanatory variables of the model of international tradeby type of disaster and by country, incorporate the impact of natural disasters into the estimation of the international trade
structure, and identify trade structures that are vulnerable to natural disasters. The frequency of occurrence of disaster types
by country is available from EM-DAT (an international disaster database). Specifically, we will add these frequencies to the
explanatory variables of the international trade model for floods, storms, droughts, wildfires, and extreme temperatures. In thecurrent model, we referred to the Shared Socioeconomic Pathways of the Intergovernmental Panel on Climate Change (IPCC)
for future greenhouse gas emissions and socioeconomic indicators by country. However, because there is no database containing
the future values of disaster frequency, we will identify scenarios that significantly affect the trade structure by setting a large
number of scenarios for increasing the frequency. In addition, we will analyze how closely related the affected trade structure is
to Japan's final demand using the previously constructed database.
We are also considering adding yield data of 10 major crops to the explanatory variables to improve the model for agricultural
products. This would involve the use of historical data from the World Food Organization and future yield estimates obtained in
Sub-Theme 3. Through this analysis, we will examine the risks to Japan's food supply resulting from changes in the future trade
structure of agricultural products in the face of changes in crop yields and disasters caused by climate change.

References
・Wakiyama, Takako, Manfred Lenzen, Ryosuke Bamba, Keisuke Nansai (2020) “Flexible multiregional input–output database for city-levelsustainability analysis in Japan,” Resources, Conservation & Recycling, 154, 104588.
・Wakiyama, Takako, Manfred Lenzen, Futu Faturay, Arne Geschke, Arunima Maliki, Jacob Fry, Keisuke Nansai (2019) “Responsibility for food loss
from a regional supply-chain perspective”, Resources, Conservation & Recycling, 146, 373-383.
－ 11 －

What impact will climate change haveon Japan's food security?
Sub-theme 3: T he effects of changes in food production due toclimate change impacts on food imports in Japan
Background
The world's population continues to grow, making forecasting future crop productivity an important issue. It has been suggested
that crop production should be about double the current level to meet the predicted population growth through 2050. Japanproduces most of its rice domestically, but it imports more than 70% of its grains and about 50% of its meat and fish. Therefore,
Japan may have difficulty supplying food if severe weather patterns significantly decrease food production outside Japan. Future
global crop productivity will be directly linked to food security in Japan. Many studies have analyzed the impact of climatechange on crop productivity in various countries, and numerous studies have shown that future crop yields will decrease
globally. When considering future food security in Japan, it is necessary not only to analyze changes in crop yields in Japan but
also to predict changes in crop yields throughout the world.
There are two important points to consider in the above-mentioned crop research from the viewpoint of food security. One
is that many of the studies use process-based models (mathematical models that consider the physiological processes ofcrop growth), and uncertainty in predictions is not taken into account. The other is that most of the studies are limited tomajor crops, and other types of crop are not covered. Given the wide variety of crops that Japan imports, we need to estimate
the effect of climate change on a wider variety of crops. In addition, from a policy-making perspective, we need to include
evaluations of uncertainty in our predictions of potential crop yields.
Figure 3. Effect of temperature and precipitation on crop yields

Figure 4. Crop yield change rate (%)

The horizontal axis shows the annual average temperature (ºC) during
the growing period, and the vertical axis shows the precipitation (mm/day). For oats, rapeseed, rye, and wheat, the values are averaged 2
months before the harvest date. Red indicates a decrease in yield, andblue indicates an increase. The purple lines indicate 20 °C.

The upper and lower panels show the upper and lower
values of the 95% confidence interval. The crop yieldchange rate (%) relative to 2010s for each country is
estimated using multiple GCM outputs.

Project members
Gen Sakurai, Ryoko Morioka (fiscal year 2019-2020) (National Agriculture and Food Research Organization (NARO))－ 12 －

Research outline
In this study, we analyzed the relationship between crop yield and climate change for multiple crops that are important as staple
foods, feeds, and edible oils (barley, cassava, corn, oats, wheat, rice, sorghum, soybean, sugar beet, sunflower, sweet potato,yam, and rye). To investigate the effects of climate on crop productivity on a global scale, we used past meteorological dataand crop yield data for statistical modeling. Past meteorological data were obtained from the Climatic Research Unit (CRU),
and FAOSTAT data from 1980 to 2015 were used as crop data. Whereas the resolution of CRU data is 0.5 degrees, that of the
FAOSTAT data is the country level. Therefore, CRU data were aligned with cultivation area data, cultivation calendar data, andaltitude data, and the average temperature and average precipitation during the cultivation periods were calculated for eachcountry. Using these data, we analyzed the relationship between climate factors and crop yields using the generalized additivemodel developed.
As a result of the statistical analyses, we could obtain impact evaluation functions for potential crop yields with respect to theaverage temperature and precipitation during the cultivation period for various crops. The results for several crops are shownin Figure 3. Despite the complex interactions with precipitation, elevated temperatures had a negative impact on yield for mostcrops. On the basis of the obtained impact evaluation functions, we estimated future crop yield under the multiple climate
scenarios (Representative Concentration Pathways: RCP2.6, RCP4.5, RCP6.0, and RCP8.5) using five Global Climate Models(GCMs) (GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, MIROC-ESM-CHEM, and NorESM1-M). The result for barley
under the RCP8.5 scenario (the high emission scenario) is shown in Figure 4 (for yield change around 2050). Even at the upper
end of the 95% confidence interval, results indicate a high probability of yield loss throughout the world. Table 3 shows theglobal average (weighted by harvested area) yield change under RCP8.5 around 2050. Significant yield losses were predicted
for barley, sorghum and corn. Because a positive effect of increased carbon dioxide on C4 plants cannot not be expected, thedecrease in the yield of maize is of particular concern.

Future plans
This study also predicts future crop yields using a process-based model. During the final year of the project, we will compare
results from the generalized additive model and the process-based model. In collaboration with Sub-Theme 2, we will also
analyze how changes in crop productivity under future climate scenarios will affect Japan's food security along with changes intrade. In addition, we will conduct a survey on what adaptation measures can be adopted in each country and comprehensively
analyze the impact of climate change on Japan's food security.
Table 3. Global average of crop yield change rate (%) around 2050 under RCP8.5 (average of five GCMs)
Average yield change(%, relative to year 2016)

95% confidence interval(upper)95% confidence interval(lower)Barley-10.83- 7.73-13.83Maize- 4.97- 1.86- 7.97

Oats (Winter)- 0.60  2.59- 3.69Rice- 1.77  0.59- 4.07

Rye (Winter)  0.33  3.69- 2.92

Sorghum- 6.98- 3.04-10.76

Soybeans- 4.96- 1.86- 7.94

Sugar beets- 5.68- 2.82- 8.44

Sunflower- 6.77- 2.64-10.72Winter wheat- 1.14  1.93- 4.12Crop

References
・Christoph Müller et al. (incl. Gen Sakurai) (2019) "The Global Gridded Crop Model Intercomparison phase 1 simulation dataset," Scientific Data 6(50), 1-22.
・Jacob Schewe et al.(incl. Gen Sakurai) (2019) "State-of-the-art global models underestimate impacts from climate extremes," Nature Communications 10(1005),
1-14.
・Ryosuke Fukuyama, Gen Sakurai (2019) "Comparison of the robustness of methods for estimating leaf development for crop growth models," Journal of Agricultural
Meteorology 75(2), 76–83.

－ 13 －

External emergency needs for extreme
events in Asia
Sub-theme 4: Climate fragility risk in Asia
Background
Climate change can exacerbate extreme climatic events, such as floods, typhoons, and droughts. The socioeconomic impacts ofthese events can be debilitating for all countries, irrespective of their developmental status. Some of the impacts will be largely
unmanageable if countries lack relevant experience and expertise, necessitating significant external emergency assistance.
Approaches used in external emergency assistance are improving constantly based on the experience gained in major disasters.
Countries are improving their capacity to be self-reliant in disaster relief and response, but it is apparent that there is still aneed for improving coordination mechanisms, especially in the face of potentially devastating extreme events in the future.
Important questions need to be answered, such as when to call for external assistance, when to respond to such calls, and how
the assistance can be delivered.

Research outline
This research examines the external factors in terms of extreme climatic events that affect the well-being of countries withwhich Japan has strong bi-lateral relations and the climate security implications for Japan. The study evaluates the possibility ofapplying the critical threshold concept, which suggests that countries that receive external emergency assistance tend to havea critical threshold in terms of the scale of emergency events and the capacities at which they tend to seek external emergency
assistance. If such critical thresholds exist, then it is possible for countries such as Japan that reach out with emergency
assistance to design their external assistance in such a way that the support being offered can maximize the climate security ofboth the recipient and donor countries.
To measure the relative climate fragility of countries, we developed the Climate Fragility Risk Index (CFRI), which consists of
the indicators shown in Table 4. The fragility of a country refers to a situation in which a government fails to provide a nation
with security. Climate change is seen as multiplier of threats that worsen fragility. Countries with a high CFRI tend to be
exposed to the physical impacts of climate change, as well as lack the ability to provide their own effective relief assistance.
Therefore, they will become more reliant on international emergency assistance. Figure 5 shows CFRI values for countries in
Asia and Oceania. The countries clearly differ in the extent of climate-fragility risk. The average CFRI for developing countries
in Asia was 0.76, whereas it was 0.66 for the developed countries. The differences among the countries were largely a resultof variations in exposure to sea level rise (Vietnam and Thailand are highly vulnerable) and volatility in food prices (Pakistanscored the highest). Among the developed countries, Australia had a relatively high CFRI because of its high exposure to water
stress and high levels of food price volatility.

Future plans
The CFRI framework could be used to identify underlying factors of climate fragility risks, such as competition for resources,
extreme weather events, migration, food price volatility, and the unintended effects of policies. Our goal is to determine
the relationship between a country’s state of climate fragility and its dependence on external assistance. We also plan todemonstrate the possibility of developing the critical threshold concept by using available data from India and Indonesia.
Furthermore, we plan on conducting a survey of experts using the Delphi method to elicit important measures to strengthen
external emergency assistance and maximize the climate security of recipient and donor countries.

Project members
Kentaro Tamura, Sivapuram V.R.K. Prabhakar, Mariko Ikeda (Institute for Global Environmental Strategies (IGES))
Rajib Shaw (Keio University)－ 14 －

Table 4. List of indicators used in developing the Climate-Fragility Risk Index (CFRI) (Prabhakar & Shaw, 2019)

Figure 5. Climate fragility of selected countries in Asia and Oceania(Prabhakar & Shaw, 2019)

References
・P rabhakar, S.V.R.K., R. Shaw (2019) Globalization of local risks through international investments and businesses: A case for risk communicationand climate fragility reduction. UNISDR Global Assessment Report 19 Contributing Paper.
・P rabhakar, S.V.R.K. (2020) State Fragility and Human Security in Asia in the Context of Climate and Disaster Risks. In: Climate Change, Disaster
Risks, and Human Security - Asian Experience and Perspectives. Springer, [In Print].
－ 15 －

Climate change as a security issue
Sub-theme 5: T heoretical aspects of climate change andsecurity concepts
Background
In Europe and the United States, the impacts caused by climate change have been discussed in the framework of a security
threat rather than only in the conventional sense as environmental issues. Over the course of the past decade or more, theconcept of “climate security” has developed from these discussions. The concept remains a relatively new research topic andpolicy agenda item.
The concept of climate security has three stages. (1) Extreme weather resulting from climate change causes negative impacts
including floods, droughts, severe typhoons, and land erosion due to sea level rise. (2) Negative impacts on fragile ecosystems
lead to loss of crops, reduced yields from fishing, and economic downturns. These in turn cause water and food shortages andthe forced displacement of people (i.e., environmental refugees). (3) As a result, societies become more destabilized, politicalconditions deteriorate, and in the worst case, they escalate into armed conflict. In contemporary international society, developed
countries and international organizations have no choice but to become indirectly engaged in regional conflicts even if they are
far from the home country or region. Experts have pointed out that a country’s military itself must have a system and equipment
to be able to respond to extreme weather.
Thus, climate change is recognized as a “threat multiplier” that amplifies existing threats, and it directly or indirectly posesa security threat to countries throughout the world. Therefore, the climate security concept is becoming established as away to address climate change in terms of security. However, research in this area is lacking in Japan, which has offered little
leadership on this topic in the global scientific community. Over the past several decades, Japan has not successfully integrated
its security policy with larger international security concerns. However, if climate change is a threat to security, Japan shouldbe able to contribute to the world's security policies, particularly in the fields of technology and economics related to climatechange. For these reasons, the study of climate security both as a concept and policy making is very important.
Figure 6. Structure of climate security

Project members
Seiichiro Hasui, Hiroshi Komatsu (Ibaraki University)－ 16 －

Research outline
The purpose of the research in this sub-theme is to discover how the impacts and risks associated with various climate-related
economic and social changes will affect Japan's “security in a broad sense" through analyzing scientific and political discourse
throughout the world.
Current discussion on Japan's climate security can be divided into domestic factors and foreign factors. In terms of domestic
economic and social changes, discussions have mainly focused on human security and economic losses, including those related
to climate disasters, public health, and adverse effects on agriculture, forestry, fisheries, and tourism. Foreign concerns include
political instability caused by a country’s inability to respond adequately to the adverse effects of climate change, which could
hinder the activities of Japanese companies. Other important topics are displacement of people, changes in shipping routes in
the Arctic Ocean, changes in fishing grounds, and energy issues.
By surveying scientific and political research on climate security in Europe and the United States, we have found that theconcept of climate security can be positioned as an argument that links and integrates various security fields, including
traditional security and resource security, as shown in Figure 6. The links between the various security areas vary in strength.
For example, based on the number of scientific papers and their content, the concepts of food security and energy security
appear to have stronger linkages than some of the other security fields.
Furthermore, it is clear that resource security affects traditional security. Even though they are not directly connected in
Figure 6, it is important to account for maritime security when considering food security, particularly shipping routes. Also,
maritime security and energy security are important elements of the national security of Japan, a country with very limited
natural resources. Water security is also extremely important when addressing issues related to human security. In this way,
climate security is linked to all of the various security issues, which is why it is located as the origin or central connection point
in Figure 6.
The final goals of this research are to (1) collect knowledge about the impact of climate change on Japan’s security and (2)present a unified theory of "climate security” policy that aims to reduce the risks related to climate change by considering not
only the Japan-US alliance, which is the foundation of Japan’s security, but also the relationships between the other developed
and developing countries.

Future plans
In the future, we plan to propose localized “climate security” policy options for Japan after analyzing and integrating theknowledge gained from scientific research papers and policy documents from the international community.
We have found that the appropriate response to climate change requires the cooperation of military and non-militaryorganizations. Military organizations generally have the equipment and supplies necessary for relevant response activities andcan operate in harsh conditions and environments such as those encountered in disaster-stricken areas. In Japan, disaster relief
provided by the Self-Defense Forces has been identified as the most expected role of the nation (Cabinet Office, 2018, “Opinion
Poll on JSDF and Defense Issues”).
Because the effects of climate change are borderless, security measures against these effects will lead to the formation of a newinternational order. An example of a major climate security risk in East Asia is super typhoons, even if any particular typhoon
does not hit the Japanese islands. If Japan can take a leading role in regional disasters such as typhoons, it will build trust withneighboring countries. Therefore, organizations or institutions that can oversee and respond to security risks resulting fromclimate change in East Asia are essential. In addition, it is important to improve governing capacity to realize adaptive policies
that reduce climate disasters, and for that purpose, it is necessary to build and maintain linkages between domestic policies andforeign assistance.

References
・Seiichiro Hasui (2020) “From Development and Security Paradigm to Post-Security Era”. Akira Hirai (ed). Now of Peace Studies: A sketch thatconnects the earth, oneself and the future. Kyoto: Horitsubunksha, 80-94. (In Japanese)・Seiichiro Hasui and Yukio Maeda (2020 forthcoming) “Chapter 6: Global Environment/ Energy Issues and Climate Security”. Atsushi Minamiyama
and Yukio Maeda (eds). Critical Security Studies. Kyoto: Horitsubunkasha. (In Japanese)－ 17 －

Risks related to Japanese territory
Sub-theme 6: Measures to address climate change risk ininternational systems
BackgroundAs the impacts of climate change become more serious around the world, various international institutions are beginningto deal with climate change risks. The UNFCCC and the Paris Agreement are aimed at addressing losses and damages
resulting from climate change in developing countries, especially those that can be partially mitigated by reducing GHG
emissions as well as by implementing various adaptation measures. Furthermore, other international institutions that are lessdirectly relevant to climate change have started to act against climate change by integrating climate change risks into theirorganizational objectives. In recent years, the UN Security Council has also come to call for climate change risk analysis andstrategic management to address conflicts. Climate change risk is now considered to lead to social instability, as well as threateninternational peace and security. Similarly, climate change and its associated risks can affect Japan's security as well.

Research outline
The UNFCCC stipulates the general obligations of developed countries to support developing countries on the assumption thateach Party deals with climate change risks on its own. In 2013, the Warsaw International Mechanism for Loss and Damage wasestablished to address climate change risk in developing countries as part of promoting adaptation measures (policies to prepare
for climate change impacts). This mechanism has three missions: to gain an understanding of comprehensive risk management
and strengthen knowledge; to support dialogue with related organizations, enhance collaboration, and promote synergies; and tosupport actions, such as funding, technology, and capacity development.
The Paris Agreement sets out global goals for adaptation (Article 7.1) to promote adaptive capacity, strengthen resilience, andreduce vulnerability to climate change, while encouraging the Parties to implement adaptation planning processes and actions.
It also sets out the obligations of the Parties to cooperate in strengthening adaptive action (Articles 7.7, 7.9). In addition, theWarsaw International Mechanism is placed under the Conference of the Parties, serving as the meeting of the Parties to theParis Agreement (CMA) (Article 8.2). In the work plan (2017–2021) agreed upon at the 22nd Conference of the Parties (COP22)
in 2016, five strategic pillars were set: (i) slow onset events, (ii) non-economic losses, (iii) comprehensive risk management
approach, (iv) displacement of people, and (v) actions and support. An expert group was established for (i)–(iv), and a Fiji
Clearinghouse for risk transfer, such as insurance, was established under (iii).
The strategic pillars (i), (ii), and (iv) prioritize actions to protect people from climate change risks, and (iii) prioritizes risk
countermeasures. However, to date, no specific measures have been taken except for (iv), although the Fiji Clearinghouse(iii) has seen sporadic information exchange, and initiatives outside the climate regime are making tangible progress. For
example, the InsuResilience Global Partnership for Climate and Disaster Risk Finance and Insurance Solutions, which consistof governments, international organizations, civil society, and private companies, was set up after the G20 in 2017 to address
climate change risk.
Displacement of people (iv), which is the most studied field among the five pillars, is generally carried out in collaboration withintergovernmental organizations such as the UN High Commissioner for Refugees, International Organization for Migration,and International Labor Organization, as well as non-governmental organizations. The goal is to achieve a coordinated andintegrated approach with respect to the displacement of people and other international human rights protection obligations.
In addition to the aforementioned displacement of people, other measures to respond to climate change risks are being
promoted by international institutions outside the official climate regime. The UN Human Rights Council, as part of its 2015
Human Rights Council Resolution 29/15 (Human Rights and Climate Change), conducted a detailed study on the impacts ofclimate change. Human Rights Council Resolution 35/20 (Human Rights and Climate Change) requested that the UN High

Project members
Yukari Takamura (University of Tokyo)－ 18 －

Commissioner for Human Rights prepare a report (A/HRC/38/21) on the effects of slow onset events and the protection ofhuman rights of transnational immigrants. Impacts of climate change are likely to negatively impact human rights in some areas.
Climate change measures should therefore be in line with internationally established human rights protection obligations.
In addition, since 2017, the UN Security Council acknowledged in its resolution that adverse impacts of climate change, such as
droughts and food shortages have contributed to the occurrence of conflicts in Africa. As noted in previous sub-themes, climatechange risks threaten international peace and security; furthermore, they act as “multipliers” that amplify the frequency,
intensity, and length of conflict.
Turning to Japan's security, sea level rise has become a problem that affects the survival of the Pacific island nations, and Japanis not an exception. A rising sea level could lead to the loss of some of Japan’s Exclusive Economic Zone and further complicate
territorial and fishery issues with neighboring countries (Figure 7). For this and other reasons, it is necessary to conduct
climate change impact assessments while paying attention to the climate change risks that are of great importance to Japan fromthe perspective of economic benefits and security.

Future plans
We need to further investigate howvarious international institutions,
i nclud i ng b ot h cl i m ate a nd non cl i m ate -rel ated i nst it ut ions, c a n
integrate climate change risks into
their respective activities and aim
for effective minimization of risks.
We will proceed with research to
examine the structure of desired
governance. We aim to clarify therisks that are internationally importantand determine appropriate responses
through international collaboration.
We also will clarify priority issues andmeasures to be taken as part of Japan's
diplomatic activities.

Figure 7. Japan’s Exclusive Economic Zone (EEZ). Small islands are importantelements in the determination of the size of the EEZ.

（Source: Japan Coast Guard Website, https://www1.kaiho.mlit.go.jp/JODC/
ryokai/ryokai_setsuzoku.html）

References
・Institute for Future Initiatives website: https://ifi.u-tokyo.ac.jp/en/－ 19 －

Conclusion: Preparing for theCompound Risk of Climate Change
Based on the results of the research conducted on the six risks that compose the compound risk of climate change, the risks
that Japan faces become clearer. The question then arises: How should we prepare for these risks?
First, Japanese companies must sustain their business activities while facing various climate-related risks. The risks varydepending on the type of business and the countries with which a company trades. Related risks include not only material risks
such as supply chains, but also non-material risks such as corporate reputation. It is necessary to consider what kind of climatechange risks each company is exposed to and prepare for those risks in many ways. The Japanese economy depends on importsof goods from abroad. In the future, it is expected that frequency of abnormal weather events will increase overseas, so it isnecessary to reconsider Japan’s procurement processes. For example, it may be better to build a system that allows rare metals
to be reused domestically rather than to rely on imports.
The same can be said for food, in the sense that Japan relies heavily on food imports. This research project focuses only on
basic grains such as wheat and soybeans, but other crops such as coffee, cacao beans, and vanilla beans will also be affected byclimate change. In addition, the temperature of seawater could affect marine ecosystems and fisheries in the future. As withother imported goods, Japan needs to consider its future sources of food.
Floods and typhoons are a popular topic in Japan, but natural disasters that occur overseas receive much less attention. Many
countries are suffering from natural disasters that are as severe as or even worse than Japan’s every year. In developing
countries, these disasters may cause not only physical damage but also social unrest. Japan provides humanitarian anddevelopment assistance to countries in the Asian region in particular, but to continue to provide effective assistance, Japan must
pay attention to a wide range of climate change risks, including sociopolitical risks.
In many studies, mostly published by European and American scholars, the compound risks of climate change are dealt with
under the concept of “climate security”. The Security Council has addressed climate change as it affects people (climate
refugees) who can no longer live in places where they used to live because of abnormal weather and rising sea levels. In
addition, conflicts have arisen because of increased competition for food and water due to droughts. Until now, such problems
have seemed to be unrelated to Japan, but Japan may become involved in the near future, and it needs to start taking part in the
climate security discussion.
Japan is a country surrounded by the sea. Sea level rise, changes in marine ecosystems, and melting sea ice in the Arctic all
will have various effects on Japan’s national security. It is necessary to consider these kinds of climate change risks, including
factors affecting Japan’s relationships with neighboring countries.
The most efficient way to minimize climate risk itself is to reduce GHG emissions (i.e., impose mitigation measures). Today's
average global temperature is already 1 °C higher than the average temperature in the pre-industrial period, causing heat waves
and other extreme weather regionally. The Paris Agreement aims to keep the average global temperature increase at less than
2 °C and within 1.5 °C if possible. To reach that goal, we would have to have net-zero global GHG emissions by 2050.
The world has changed dramatically in the spring of 2020 because of COVID-19. GHG emissions declined temporarily as
people's mobility around the world was restricted and production activities declined. However, emissions will increase once
the world economy recovers. In Europe and the United States, notions such as “green recovery” or “build back better” arebeing proposed, which would concentrate investments in rehabilitating the coronavirus depressed economy to sectors that are
effective in reducing emissions, such as renewable energy and information technology. A system that comprehensively manages
all risks, including climate change risks and various other risks, is required around the world.

－ 20 －

Compound Risks of Climate Change:
Implications to Japanese economy and society

Issue date

September 2020

Chief author

Yasuko Kameyama (NIES)

Contact info

ykame@nies.go.jp

National Institute forEnvironmental Studies