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LETTER
Public support for climate adaptation aid and migrants: a conjoint
experiment in Japan
Azusa Uji1,∗, Jaehyun Song2, Nives Dolšak3and Aseem Prakash3
1Kyoto University, Kyoto, Japan
2Kansai University, Osaka, Japan
3University of Washington, Seattle, WA, United States of America
∗Author to whom any correspondence should be addressed.
E-mail: uji.azusa.2z@kyoto-u.ac.jp
Keywords: climate change, aid, migration, adaptation, survey experiment, conjoint analysis, public support
Supplementary material for this article is available online
Abstract
We examine public support in Japan for overseas climate adaptation assistance via foreign aid and
accepting immigrants. Using a survey-embedded conjoint experiment (N=2815), we focus on
seven attributes of an adaptation policy package: (a) the continent in which the country is located;
(b) the types of extreme weather event this country faces; (c) the volume of climate aid; (d) the
number of climate migrants (e) Japanese exports; (f) Japanese imports, (g) the country’s record of
voting with Japan in the United Nations. We find that while respondents are indifferent to aid
volume, their support diminishes as the number of migrants increases. Moreover, support is higher
for Asian countries, that provide export markets, vote with Japan, and where the effects of climate
change are gradual. Importantly, we find that public support is not influenced by benchmarking of
Japan’s or peer G7 countries’ past aid or immigration levels.
1. Introduction
Climate change is a defining issue of our times.
Because developed countries have contributed most
to accumulated greenhouse gas emissions, they
bear substantial responsibility for mitigating climate
change. This is why the 1992 United Nations Frame-
work Convention on Climate Change enshrined the
principle of common but differentiated responsibility
regarding emission reductions.
Because climate change is already in motion,
there is an emerging international consensus that
developed countries should also support developing
countries to adapt. We focus on two types of over-
seas adaptation assistance: foreign aid and accepting
climate migrants. Adaptation aid could help devel-
oping countries to enhance their resilience by say
building irrigation systems to address the increased
frequency of droughts or helping communities relo-
cate from coastal areas in response to rising sea
levels (Mirza 2003, Huq et al 2004, Arndt and Tarp
2017). Accepting migrants is another dimension of
climate adaptation. As per some estimates, by 2050,
the number of climate migrants, moving either within
their countries or across borders, will reach 200
million4.
Both overseas aid and accepting migrants could
generate domestic opposition. Developed countries
tend to show aid fatigue because there is a percep-
tion that aid funds are misused in recipient countries
(Bauhr et al 2013). There is substantial literature on
the domestic backlash to international migration in
Europe and the United States (Dowd and McAdam
2017, Shehaj et al 2021). To some extent, this backlash
can be found in East Asia as well. In South Korea, the
ban damunhwa (‘anti-multicultural’) sentiment has
taken hold, where immigrants are blamed for crime
spikes. Peng (2017) points out that while developed
countries tend to rely on foreign care workers, Japan
4https://reliefweb.int/report/world/climate-migrants-might-rea
ch-one-billion-2050. A recent White House report, ‘Impact
of Climate Change on Migration,’ puts the number at 143
million for Sub-Saharan Africa, South Asia, and Latin Amer-
ica. There is no authoritative estimate of the proportion
of climate migrants that are likely to relocate to another
country, although some media reports suggest it to be
about 25%.
© 2021 The Author(s). Published by IOP Publishing Ltd
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
and South Korea restrict their immigration, despite
facing a shortage.
While many policy makers have noted that over-
seas adaptation aid can support individuals cope bet-
ter with climate-induced changes (and therefore not
emigrate), this is among the few papers that test pub-
lic support in Japan for a policy package that includes
varying levels of both climate aid and migration. We
selected Japan for three reasons. Because Japan is
a major climate donor5, it is important to under-
stand public support for overseas climate adapta-
tion assistance6. Second, immigration is not a hot-
button issue in Japanese politics. Unlike Europe and
the USA, there is no recognizable right-wing popu-
list movement against immigration. At the same time,
it is not clear how the Japanese public will react if
there is a sudden increase in the volume of climate
migrants—Asian countries, in particular, are projec-
ted to experience a substantial climate-induced out-
migration. Hence, the uncertainty about the public
response to migration, the projected surge in Asian
migration, and whether Japanese respondents impli-
citly trade-off aid against migration are important
issues to investigate in the study of global adaptation
politics.
To test the Japanese public’s willingness to sup-
port an overseas adaptation policy package, we
administered a survey-embedded conjoint experi-
ment (N=2815). The policy package has seven
dimensions: (a) the continent in which the country is
located; (b) the types of extreme weather events this
country faces; (c) the volume of climate aid that the
country receives from Japan; (d) the number of cli-
mate migrants that Japan accepts from the country;
(e) Japanese exports; (f) Japanese imports; and (g) the
country’s record of voting with Japan in the United
Nations.
Our main finding is that while respondents are
indifferent to aid volume, their support diminishes
as the number of climate migrants increases. We also
find that public support is higher for assistance to
Asian countries (as opposed to African and Latin
American countries), countries that import from
Japan (but not those which export to Japan), and
countries that vote with Japan in the United Nations.
Overseas countries might experience different types
of climate-induced challenges. We find that sea-level
rise and droughts, whose effects are felt gradually,
seem to generate more public support than dramatic
events such as floods, typhoons, and wildfires. Finally,
5https://donortracker.org/japan/climate
6The OECD countries have committed to $100 billion per
annum climate aid starting 2023. However, African countries and
the group of Like-Minded Developing Countries (LMDCs), are
demanding $1.3 trillion annual aid starting 2030. In the light of
recent climate discussions at COP 26 in Glasgow, there is an emer-
ging consensus on a 50/50 split between mitigation and adaptation
aid. Thus, major donors such as Japan might soon be providing
substantially higher levels of adaptation aid.
we find that public support is not influenced by
benchmarking with Japan’s previous aid and immig-
ration levels, or those of its peer G7 countries.
2. Literature review
An extensive foreign aid literature examines why
donors give, how much, and to whom (Lundsgaarde
et al 2010). Scholars have explored aid allocation
in the context of climate and environmental aid as
well (Hicks et al 2010), especially mitigation aid
(Halimanjaya and Papyrakis 2015). In recent years,
there is an emerging literature on adaptation fin-
ance because developing countries lack resources to
adapt effectively (Donner et al 2016) and the rising
emphasis on adaptation in policy discussions (such
as Article 9 of the 2015 Paris Agreement as well
as the 2021 Glasgow COP26 meeting). Moreover,
while the literature examines public support in donor
countries for foreign aid (Milner and Tingley 2011),
public support specifically for climate aid remains
underexplored. Therefore, our study contributes to
an important but understudied issue in the context
of climate aid.
Scholars have studied different aspects of climate
migration such as its media portrayal (Sakellari 2021),
securitization (Boas et al 2019), and its drivers (Rios-
mena et al 2018). While there is a well-developed liter-
ature on public support for immigrants in host coun-
tries, the extent of support for climate migrants, in
particular, is not clear (Bansak et al 2016, Hermanni
and Neumann 2018, Ghosn et al 2019, Abdelaaty and
Steele 2020, Rich et al 2021). In recent years, schol-
ars have employed experimental tools to assess pub-
lic support for both internal and international climate
migrants. For example, Helbling (2020) has examined
support for international climate migrants in Ger-
many, and Hedegaard (2021) has explored support
in Denmark for international climate migrants in
relation to economic migrants and asylum-seeking
migrants. Spilker et al (2020) have assessed public
support for internal climate migrants in Vietnam and
Kenya, while Castellano et al (2021) have examined
support for Rohingyas and internal climate migrants
in Bangladesh.
There is a body of literature examining the link
between aid and migration, but their findings are
inconclusive. Some report that aid deters emigration
(Gamso and Yuldashev 2018) while others find no
relationship (De Haas 2007, Berthélemy et al 2009;
Clemens 2014). But the scholarship looking specific-
ally at the relationship between climate aid and migra-
tion is sparse (exceptions include Runfola and Napier
2016, Stanley and Williamson 2021). This is among
the first studies to explore the link between climate
aid and migration in the context of public support for
a policy package that includes different levels of over-
seas aid and immigration.
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Environ. Res. Lett. 16 (2021) 124073 A Uji et al
We make a methodological contribution as well.
In the first-generation ‘aid and public opinion’ stud-
ies, researchers worked with existing surveys (such
as the World Values Survey) or administered original
surveys (Stern 1998, Paxton and Knack 2012, Henson
and Lindstrom 2013). In recent years, a growing num-
ber of researchers, are employing survey experiments
to study how different dimensions or framing of
foreign aid influence public support. For example,
Hurst et al (2017) assessed how costs, effectiveness,
and impact of aid influence public support. Baryam
and Holmes (2020) analyzed the informational effect
of aid efficacy, deservingness, and specific country
names. Kiratli (2020) examined how public support is
conditioned by recipients’ political regimes and spe-
cific country names. The implication is that public
support for aid is conditioned by its various dimen-
sions such as who gets aid, why, and whether aid will
be used appropriately. In other words, as Doherty
et al (2020) and Heinrich and Kobayashi (2020) sug-
gest, survey respondents assess aid as a ‘policy pack-
age’ with multiple dimensions instead of a single
attribute such as its total price tag (Blackman 2018,
Heinrich et al 2018, Milner and Tingley 2010). This
is perhaps the first paper to employ the ‘policy pack-
age’ approach to examine how various dimensions of
adaptation aid might influence public support.
3. Argument
The classic migration models have noted the role of
both ‘push’ and ‘pull’ factors in encouraging migra-
tion (Todaro 1969). For instance, if migration is
politically unpopular in developed countries (a ‘pull’
factor), they might be more willing to provide for-
eign aid to enhance developing countries’ economic
growth or, in case of climate migration, its resili-
ence (a ‘push’ factor) to extreme weather events.
Indeed, President Biden has recently made a case to
increase foreign aid to Central America to reduce the
incentives of their citizens to migrate to the United
States7. While scholars note the nexus between for-
eign aid and migration (Angelucci 2015, Berthélemy
et al 2009, Lanati and Thiele 2018, Dreher et al 2019,
Marchal et al 2021), they have not explicitly tested
how this might shape public support in the context
of climate aid.
Adaptation aid is aimed at enhancing climate
resilience while development aid seeks to support
(primarily) economic growth. In some instances, cli-
mate aid might have a spillover effect on economic
growth (such as building new irrigation systems)
while in other cases it might help create or improve
infrastructure such as sea walls or river embankments
with no direct spillovers on economic growth. What
7www.nytimes.com/2021/06/06/world/americas/central-america-
migration-kamala-harris.html?action=click%26module=Top%
20Stories%26pgtype=Homepage
is crucial for our paper is that governments tend to
justify development aid and climate aid using differ-
ent rationales. Hence, support for foreign aid per se
might not correctly reflect support for overseas cli-
mate aid. This argument holds for migration as well:
public support for generic migrants and economic
migrants might differ from that for climate migrants.
Studies suggest that public support for foreign aid
varies by recipient country characteristics (Baryam
and Holmes 2020, Doherty et al 2020, Kiratli 2020).
Arguably, this insight might hold for climate adapt-
ation assistance as well; that is, public support for
climate adaptation assistance, be it aid or immigra-
tion, might vary by which countries receive assistance.
People may favor some countries due to racial or geo-
graphical reasons. Spilker (2020) and Castellano et al
(2021) also consider the role of ethnicity in the con-
text of internal climate migration. We propose:
Hypothesis 1: Support for the policy package will
be higher for countries that are in the
same continent (Asia).
Hypothesis 2: Within Asia, support for the policy
package will be higher for a coun-
try that is in geographical proximity
(Cambodia).
As we note subsequently, we selected four coun-
tries: Bangladesh, Cambodia, Peru, and Tanzania.
Our objective is to test for the role of both ethni-
city and geographical proximity. Moreover, we selec-
ted countries with which Japan has trading relations
and which experiences specific types of natural dis-
asters we have mentioned in the conjoint. Based on
these multiple factors, we included two Asian coun-
tries which varied in geographical proximity along
with African and South American countries.
Furthermore, the public might be more support-
ive of climate adaptation to countries that face sud-
den extreme weather events (Helbling 2020, Spilker
et al 2020, Castellano et al 2021). This is because
these events could be viewed as bad luck over which
individuals have neither any control nor much time
to prepare for them. Hence, the luckier people else-
where might feel an obligation to help them. We
propose:
Hypothesis 3: Support for the policy package will
be higher for countries that need
to adapt to sudden extreme weather
events.
Aid often has an instrumental dimension; schol-
ars note donors often provide aid to countries they
trade with (Dolšak and Dunn 2006, Lundsgaarde et al
2010). Arguably, public support for climate adapta-
tion assistance might depend on Japan’s bilateral eco-
nomic linkages with the recipient country (Doherty
et al 2020, Heinrich and Kobayashi 2020).
3
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
Hypothesis 4: Support for the policy package will
increase for countries that have eco-
nomic ties with Japan
Donors sometimes employ foreign aid to pur-
chase political support in international venues such
as the UN General Assembly (Doherty et al 2020,
Heinrich and Kobayashi 2020, Kiratli 2020). Miller
and Dolšak (2007) find that Japan targets foreign aid
to countries that support it in the International Whal-
ing Commission, which suggests that Japan used for-
eign aid as a diplomatic tool to solidify its interna-
tional political position.
Hypothesis 5: Support for the policy package will
be higher for countries that vote with
Japan in the UN General Assembly.
3.1. Benchmarking: peer effect and policy
continuity
Public support for adaptation aid and migration
might depend on the policies of ‘peer countries.’ As
the vast literature in prospect theory (Levy 1997) sug-
gests, boundedly rational individuals employ refer-
ence points or benchmarks in making choices. This
might be because the norm of appropriate beha-
vior (March and Olsen 1998) works as a guide for
their actions. If peer countries provide a substantially
higher volume of climate adaptation assistance, the
Japanese public might support higher aid or immig-
ration levels.
Hypothesis 6: Support for the policy package
will be higher when respondents are
provided information about aid and
migration policies of peer countries.
Similarly, given a bias for policy continuity, indi-
viduals might assess a policy package in relation to
how their country has addressed the same issue in the
past. If so, they could be more supportive if aid or
immigration volumes proposed in the policy package
are comparable to existing levels. Self-benchmarking
might also correct individuals’ misperceptions about
actual levels of aid or immigration. For example,
scholars note that because citizens sometimes overes-
timate the aid levels, public support for aid increases
once the respondents are exposed to information on
the actual levels (DiJulio et al 2016).
Hypothesis 7: Support for the policy package
will be higher when respondents are
provided information about Japan’s
past aid and migration levels.
In the next section, we outline the empirical
strategy to test these hypotheses about public support
for various types of adaptation policy package.
4. Data and methods
We administered a survey-embedded experiment to
a sample of adult Japanese citizens (in the Japan-
ese language) drawn from online panels of Rakuten
Insight in Japan (N=2815) between 8 February and
17 February in 2021. Since native Japanese speak-
ers are in the research team, we are confident that
the language is culturally appropriate. Prior to the
survey, we secured Human Subjects Approval from
our university and pre-registered our survey (https:/
/osf.io/9z4tm). Our sample is representative of the
adult Japanese population in terms of age, gender,
and region (six regions).
Conjoint analysis has several advantages com-
pared to a classic survey experiment. First, it is a more
realistic portrayal of the reality because individuals
vote on policies with multiple dimensions, involving
trade-offs. Second, conjoint allows researchers to
evaluate how specific components contribute to over-
all support for the full policy package. Lastly, because
individuals are assessing several dimensions together,
conjoint can reduce the implicit social desirability
bias (Bechtel and Scheve 2013, Hainmueller et al
2014).
Our survey was structured as follows. Participants
first read the introduction (A.2 in the appendix).
Given that many people are less familiar with cli-
mate adaptation than mitigation, in the introduc-
tion, we provide the basic knowledge on climate
adaptation assistance with a positive tone. We noted
that Japan, as a developed country, bears responsib-
ility for providing adaptation assistance to develop-
ing countries. In particular, foreign aid and accept-
ing international migrants are important instruments
of overseas adaptation assistance. After reading the
introduction and an attention check question, parti-
cipants were exposed to the conjoint experiment. We
asked to evaluate six policy pairs (sequentially) and
select the policy package in each pair they recommend
the Japanese government should adopt.
Every policy (package) has seven attributes: (a)
countries receiving assistance (Bangladesh, Cam-
bodia, Peru, and Tanzania); (b) type of climate
problem (wildfire, drought, sea-level rise, flooding,
and typhoon); (c) proposed aid levels (0, $1 bil-
lion, $2 billion, $3 billion and $4 billion)8; (d) pro-
posed number of climate migrants Japan should
accept from this country (0, 100, 250, 450, 700,
8In 2020, Japan donated $ US$16.3 billion in official devel-
opment assistance (ODA). As per OECD, 46% of ODA is for
climate-focused projects (https://donortracker.org/japan/climate,
last accesses on 2 November 2021). At the recent COP 26
in Glasgow, Japan pledged $14.8 billion for climate adaptation
aid for the next five years (https://enb.iisd.org/Glasgow-Climate-
Change-Conference-COP26-daily-report-2Nov2021, last accesses
on 3 November 2021).
4
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
Table 1. A sample set of policy proposals. ‘For reference, in 2018, major developed countries provided 886 million USD in climate aid on
average. They accepted 26 000 general (non-climate) refugees on average.’
Policy 1 Policy 2
Developing country Cambodia Peru
Extreme weather events Wildfire Drought
Give climate aid to this country (USD) per year 3 billion 1 billion
Accept climate migrants from this country per year 100 450
Value of Japanese goods exported to this country (USD) 0 1 billion
Value of goods Japan imports from this country (USD) 1 billion 2 billion
Percentage of times this country voted with Japan in the United Nations 40% 0%
Figure 1. Baseline preferences.
Note: Lines indicate 95% confidence intervals. We use robust standard errors.
1000)9; (e) economic connectivity: value of Japanese
exports to this country (0, $1 billion, $2 billion);
(f) economic dependence: Japanese imports from
this country (0, $1 billion, $2 billion); and (g)
political solidarity: percentage of times this coun-
try voted with Japan in the United Nations Gen-
eral Assembly in the last ten years (0%, 40%,
and 80%).
With respect to the order of attributes within a
set of policy proposals, we divided seven attributes
into three groups: (a) country names and extreme
weather events; (b) aid volume and migration levels;
9Since the term climate refugees is more commonly used than
climate migrants in Japan, we used the former in our survey.
(c) import, export, and UN voting. To minimize
confusion as to which country is receiving adapta-
tion assistance, we listed country names first. But we
randomized the order of attributes within the last two
groups. Then, the order of attributes was held con-
stant across the six choice tasks to limit the cognitive
burden on participants.
We randomized the values of attributes, except for
country names. These experimental settings enable us
to identify the causal effects of each attribute on pub-
lic support for the policy package. This yields a sample
of 33780 observations: 2815 (respondents) ×6
(choice tasks) ×2 (policy proposals). We dropped
528 respondents who failed the attention check
questions (our results do not change if we include
them). In the end, 2287 respondents remained in
5
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
Figure 2. Benchmarking effect.
Note: lines represent 95% confidence intervals.
our sample, which generated 27444 observations. A
balance check for covariates presented in A.1 in the
appendix (available online at stacks.iop.org/ERL/16/
124073/mmedia) shows that covariates are balanced
across various groups. In the following section, we
report baseline preferences and benchmarking effect.
Throughout our analysis, we present the conjoint res-
ults from the forced choices.
To explore if benchmarking influences public sup-
port for climate aid and immigration, we divided
participants into three groups (reference category
and two treatment groups). The reference group
received only the conjoint table without bench-
marking information. The treatment groups received
the benchmarking information along with the con-
joint table (while maintaining a comparable word
count across the groups). Respondents in the first
treatment group (self-benchmarking) were provided
information on Japan’s climate aid and migrants
Japan accepted in 2018, the most recent year for
which immigration data are available (UNHCR 2018,
OECD 2021). The treatment text reads: ‘For refer-
ence, in 2018 Japan provided 1600 million USD in cli-
mate aid and accepted 42 general refugees.’ Respond-
ents in the second treatment group were provided
with the information on average aid and migrants of
peer countries, the G7 (UNHCR 2018, OECD 2021).
The text reads: ‘For reference, in 2018 other major
developed countries provided 886 million USD in
climate aid on average and accepted 26 000 general
refugees on average.’ Note that we provided inform-
ation on the number of ‘general’ refugees instead of
climate migrants because neither Japan nor G7 coun-
tries officially accept climate migrants displaced by
climate change.
Table 1shows a sample set of policy proposals
with the benchmarking information of Japan. We
asked socio-demographic questions toward the end
of the survey. We provide the survey design with full
texts of introduction, information frames, and ques-
tions in A.2 in the appendix.
5. Results
5.1. Baseline preferences
We first report baseline preferences by policy attribute
without the benchmarking effect (that is, for the ref-
erence group only). Figure 1shows marginal means
(MMs): the average support for a policy containing a
specific attribute value, averaging over all other attrib-
utes (Leeper et al 2020).
6
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
Figure 3. Subsample analysis by gender.
Note: Lines indicate 95% confidence intervals. We use robust standard errors.
We find that while respondents are indifferent to
volumes of aid (that is, changing aid levels does not
alter their support for the policy package), their sup-
port for the policy package diminishes as the num-
ber of climate migrants increases. This might reflect
that while aid is viewed predominantly as an eco-
nomic issue, migration involves social and cultural
aspects. Furthermore, Japan is an ethnically homo-
genous country, and its citizens do not have much
experience in living with individuals of different
ethnicities.
But does the support for assistance reflect impli-
cit geographical bias? Our finding partially sup-
ports public inclination to support Asian countries.
Respondents tend to support policy packages when
assistance is provided to Asian countries instead of
Latin American and African countries. Specifically,
support for adaptation assistance to Bangladesh is
significantly higher than to Tanzania or Peru. How-
ever, support for assistance to Cambodia is not
statistically significantly different from Tanzania or
Peru. Meanwhile, respondents do not differentiate
between Asian countries (Cambodia in relation to
Bangladesh). These findings offer partial support for
hypothesis 1 (in the context of Bangladesh only) but
not hypothesis 2.
Does the public support change in response to
different extreme weather events? In contrast to pre-
vious studies (Helbling 2020, Spilker et al 2020),
support for the policy package is higher when assist-
ance is motivated to tackle droughts and sea-level rise
instead of floods, typhoons, and wildfire. This chal-
lenges our expectation outlined in hypothesis 3 that
respondents might be more willing to accept migrants
affected by sudden and visible disasters (typhoons
or floods) than gradual events (droughts or sea-level
rise). Instead, it seems they are more sympathetic
to events where the trajectory is clear even though
the visible damage is not dramatic. Perhaps, this
reveals the inevitability of damage climate change
will inflict on the country, and the moral imperative
respondents feel to support them in their adaptation
efforts.
With respect to political and economic attrib-
utes, we find respondents support policy pack-
age directed towards countries that absorb Japanese
exports (but not when Japan imports from them).
Lastly, respondents are more supportive of policy
7
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
Figure 4. Subsample analysis by age.
Note: Lines indicate 95% confidence intervals. We use robust standard errors.
package for countries that vote with Japan in the
United Nations. This supports hypothesis 4 and
hypothesis 5.
5.2. Benchmarking effect
We estimated the effects of benchmarking (with
respect to past Japanese policy and peer G7 coun-
tries). In figure 2, we report the difference of MMs
between the control group and the two treatment
groups. Even though Japanese benchmarking inform-
ation slightly reduces public support for $3 billion
aid, overall, we do not find statistically significant
benchmarking effects. These results suggest that the
provision of information about Japan’s existing policy
or the policies of its peer countries does not change
public support for the policy package. Thus, we do
not find support for hypothesis 6 and hypothesis 7.
5.3. Subsample analysis
The degree of political and social conservativeness
of individuals might affect their racial bias, risk per-
ception to different extreme weather events, and
social acceptance of foreigners. To assess hetero-
geneity in public support, we conducted subsample
analyses on baseline preference by gender, age, and
political ideology, which are often associated with
conservativeness. First, figure 3shows that the pro-
Asian bias and the support for providing assistance to
address gradual extreme weather events are less pro-
nounced among women than men. However, women
express more opposition to climate migrants as their
number increases.
In our analysis by age, we regard respondents who
are over 50 years of age as ‘old’ and the rest as ‘young’.
As reported in figure 4, respondents over 5o years
support assistance to Asian countries and for chronic
but gradual climate problems. Their opposition to
climate migrants is higher as migration numbers
increases. In contrast, such preference is not observed
among the younger generation (below 50 years).
They are indifferent to country names, gradual/sud-
den extreme weather events, and the number of cli-
mate migrants. This result probably reflects the con-
servative bias among older people (Peterson et al
2020).
Lastly, we conducted an analysis by political ideo-
logy. In our survey, we asked respondents to express
their political position by rating between 0 (left) and
10 (right). In our analysis, we categorize 0–3 as ‘left’,
4–6 as ‘neutral’, and 7–10 as ‘right’. In figure 5, we
did not find heterogeneous preferences by political
ideology (left/neutral/right). This is mainly because
8
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
Figure 5. Subsample analysis by political ideology.
Note: Lines indicate 95% confidence intervals. We use robust standard errors.
most respondents are categorized as politically neut-
ral (1207 respondents), which makes standard errors
for the results of the political left and right larger.
6. Conclusion
Our paper explored whether the policy design of over-
seas adaptation assistance affects public support in
Japan. Our main finding is that while respondents
are indifferent to aid volume, their support dimin-
ishes as the number of climate migrants increases. We
also find that public support for overseas adaptation
assistance is shaped by a pro-Asia bias, Japan’s export
to the country, the support extended by the coun-
try to Japan at the United Nations, and the types of
extreme weather events that this country has experi-
enced. Importantly, we find that public support is not
influenced by benchmarking either based on Japan’s
previous aid or immigration levels or that of its peer
G7 countries. This suggests that Japanese respond-
ents view overseas adaptation assistance neither as
a developed country’s obligations nor a continu-
ation of its existing policy. Rather, respondents seek
to assist countries that support Japan in interna-
tional forums or support its economy by providing
an export market. While the Japanese public does
show an Asian bias (though only towards Bangladesh
but not towards Cambodia), it does not differentiate
between these countries based on geographical prox-
imity and historical ties. Finally, sea-level rise and
droughts, whose effect is gradual seem to generate
more public support than dramatic events such as
floods, typhoons, and wildfires.
Taken together, we draw two implications for
the politics of overseas adaptation assistance. First,
immigration is politically sensitive even in Japan,
where immigration is not a hot-button policy issue.
Moreover, we observed low public support despite a
lengthy introduction in the survey that made a case
for why Japan should provide adaptation assistance.
This may suggest that support for climate migrants
might be even lower in the real world.
Climate migrants were not a part of the policy dis-
course when the 1951 Geneva Convention Relating
to the Status of Refugees (Behrman and Kent 2018)
was established. While the proposal to include climate
migrants in the legal definition of refugees is draw-
ing opposition in Western countries, the pushback
against this move could come from Asian countries
such as Japan as well. This means that international
9
Environ. Res. Lett. 16 (2021) 124073 A Uji et al
migration as an adaptation strategy will be politic-
ally difficult, and industrialized countries may need
to substantially increase the volumes of overseas cli-
mate aid to enhance resilience and reduce incent-
ives for out-migration. Yet, given the aid fatigue that
many developed countries experience, climate leaders
should highlight that overseas adaptation assistance
could create economic and political benefits (in addi-
tion to reducing migration). The government could
also link climate adaptation with trade agreements or
other trade promotion efforts.
Second, Japanese respondents reveal a pro-Asia
bias. Future research should explore if this involves
some implicit biases, such as racism. Prior research
shows that in South Korea, a country similar to
Japan in terms of economic prosperity and ethnic
homogeneity, the public tends to support immig-
rants from culturally similar and higher-status coun-
tries, who have well identified professional oppor-
tunities and therefore will not burden the taxpayer,
and who can speak the Korean language (Denney
and Green 2021). While Castellano et al (2021)
find Bangladesh respondents show lower support for
co-religionist Rohingyas in the context of generic
migrants, future research could explore if the religion
of the potential climate migrant affects public sup-
port given the concerns about Islamophobia (Taras
2012).
This research has several limitations. First, it
focuses on a single country. Japan is an ethnically
homogenous country where immigration is not a sali-
ent partisan issue in national politics unlike the US
or Europe. Given that Japan is a less likely case to
find anti-sentiment to climate migrants, other coun-
tries may face more difficulties in gaining the pub-
lic’s understanding on accepting climate migrants.
This research design could be replicated in other con-
texts. Second, our survey was administered during
a time when Japan did not experience any extreme
weather events. Arguably, public sentiment towards
overseas adaptation assistance could shift when cli-
mate issues are on top of the mind. Third, if sup-
port for migration depends on the ‘deservingness’
of the issue, it is not clear whether the public finds
climate migrants more or less deserving than say
migrants who seek physical security or economic
opportunities. Thus, future work should examine
how adaptation assistance might condition the per-
ceptions of the deservingness of different categories of
migrants.
Data availability statement
The data generated and/or analyzed during the cur-
rent study are not publicly available for legal/eth-
ical reasons but are available from the corresponding
author on reasonable request.
Acknowledgments
We are thankful to Liliana Andonova, Federica Gen-
ovese, Vally Koubi, Christiana Parr; participants at
the WPSA 2021, EPG 2021, and APSA 2021 meet-
ings; and three anonymous reviewers for very valu-
able comments. This research was made possible by
generous funding from Japan Society for the Promo-
tion of Science (#18KK0037 and #19K21685).
Ethics statement
We secured Human Subjects Approval from the Insti-
tutional Review Board (IRB) of University of Wash-
ington, and informed consent was obtained from all
subjects.
ORCID iDs
Azusa Uji https://orcid.org/0000-0001-9992-5908
Jaehyun Song https://orcid.org/0000-0002-3692-
6505
Nives Dolšak https://orcid.org/0000-0002-7364-
0135
Aseem Prakash https://orcid.org/0000-0002-7364-
0135
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