International climate adaptation assistance: Assessing public support in Switzerland

PLOS ONE | https://doi.org/10.1371/journal.pone.0317344 February 12, 2025 4 / 26 PLOS ONE Support for adaptation assistance in Switzerland [36–38]. Scholars have examined these issues in the context of foreign aid in totality as well as specific components such as humanitarian aid and environmental aid [39,40]. However, the extent to which different types of international linkages interact with specific country contexts to influence adaptation assistance has not been fully elaborated or explored in the literature. Acknowledging that recipient characteristics as well as economic and political linkages of the donor with recipient countries influence aid decisions, we explicitly build such expectations in our conjoint experiments. Given the “aid fatigue” in many donor countries due to perceptions about the misuse of foreign aid in recipient countries [41], and the fear that adaptation assistance might crowd out domestic donor priorities, the first hypothesis captures a baseline expectation, similar to the Japan study, that public support for the policy package will diminish as the volume of bilateral aid increases. Hence: Hypothesis 1: Support for the policy package will diminish when the volume of climate aid is high. In the European context, immigration is a salient yet complex subject in an era of popu- lism. There is a well-developed literature examining public support for immigrants in host countries [42–46], including immigrants with different characteristics such as skill level,

ethnicity, religion, and gender. There is also an emerging literature examining public support for accepting climate migrants [47–49]. Scholars have examined how aid and migration are related [50–53], including how adaptation aid might influence migration [54]. The European Union’s generous aid package to Turkey and, more recently, to Tunisia suggests that industri- alized countries are using foreign aid to hold back the inflow of migrants. Yet, it is not clear whether the public in donor countries sees the link between climate assistance and immi- gration. Arguably, given the populist backlash against immigration, the baseline expectation would be that the public in the Global North is less likely to support a policy package as the number of climate migrants increases. Hence: Hypothesis 2: Support for the policy package will be lower when the number of climate migrants to be accepted from this overseas country is high. Hypotheses 3 and 4 aim to elaborate the logic of how strategic linkage of issues at the international level may influence domestic support for different forms of climate adaptation assistance. Concerning bilateral aid, scholars note that donors have multiple motivations, including humanitarian, economic, and political. Specifically, countries might value their international standing in global forums and reward countries that vote alongside them in these venues [55]. Scholars note these sorts of “vote buying” in the context of the UN General Assembly [56–58], the UN Security Council [59,60], as well as more specialized forums such

as the International Whaling Commission [61]. While such strategic linkage between aid and support at international forums takes place at the intergovernmental level, it is less clear how such linkages at the global level might impact public support for adaptation assistance. Theoretically, we elaborate on approaches that emphasize the relevance of public opinion for development aid policies and multilateral climate finance [24,25,62] to explore if the public responds to strategic issue linkages when expressing support for bilateral adaptation packages. More specifically, the conjoint experiment tests for such linkages in the context of the UN Security Council, given that Switzerland recently became a non-permanent member of the Council, and its role as such is relatively salient in the public’s view [63,64]. Thus, we hypothesize: