Climate and Power in the South Pacific: Island States at the Heart of Strategic Rivalries

In early December 2025, the first climate migrants from Tuvalu were welcomed in Australia, fleeing rising sea levels that threaten the habitability of the South Pacific archipelago. Indeed, the Pacific Island States (PIS) are among the territories most vulnerable to the immediate effects of climate change, leading them to place climate policies at the heart of their national priorities. In this context, the PIS strive to build a plurality of strategic partnerships with the major regional powers through a strategy known as “friends to all, enemies to none” in order to secure broad financial and logistical support in the fight against climate change and to strengthen their voice within climate diplomacy forums. However, this approach is now being put to the test by the intensification of rivalries between major powers for control of the area. The South Pacific, a highly coveted space, thus constitutes the theatre of a growing entanglement between the climate vulnerabilities of island states and the competing geopolitical ambitions of major powers. An overview with Dorine Buchot, research assistant in IRIS’s “Climate, environment and security” programme in autumn 2025 and Research Manager at Carbon Free Europe.

Why is the South Pacific region particularly threatened by climate change?

The PIS are particularly threatened with uninhabitability due to sea-level rise, which endangers the survival of populations living on these territories where the coastline rarely rises more than a few metres above sea level. This rise results in particular from ocean warming (the phenomenon of thermal expansion) and the melting of ice sheets, and it manifests more strongly in this region than in most other parts of the world. Numerous scientific studies indicate that several atolls and certain parts of PIS territories could be frequently or constantly submerged as early as 2050. The phenomenon is already observable today, notably through significant coastal erosion that forces populations living closest to the shore to relocate seasonally or permanently.

The South Pacific region is also regularly hit by extreme weather events—storms, cyclones, droughts—which constitute immediate physical risks for populations. The damage caused by these phenomena represents considerable costs, amounting to several billions of dollars, and slows the economic development of the PIS, some of which—Kiribati, the Solomon Islands, Tuvalu and Vanuatu—are among the least developed island states according to the UN. The intensity and frequency of these events, as well as the costs they entail, are expected to increase in the decades ahead.

Like other regions of the world, the South Pacific is also facing extreme heatwaves, linked to the overall dynamics of global warming in average global temperatures relative to the pre-industrial era. According to the World Meteorological Organization’s 2024 report, 2024 was the hottest year ever recorded in the region, leading to significant disruptions in precipitation patterns. These changes directly affect the availability of drinking water resources and agricultural resources, but also have repercussions for population health and, more broadly, for human security in the region.

How are the interests of the PIS being weakened by the strategic interest of the major world powers in the South Pacific area?

A space of major strategic interest, the region illustrates the growing entanglement between the climate concerns of the PIS and the geopolitical ambitions of major powers. This dynamic tends to weaken the sovereignty of island states and to weigh on the coherence and durability of their policies to combat climate disruption. For several years, the nations of the South Pacific have frequently warned of the risks linked to the intensification of competition between major powers (the United States, China, Australia, New Zealand, France) for control of the area, attracted by its abundant fishery resources and critical minerals and by its direct proximity to the major so-called Asia-Pacific sea lanes, now the core of global trade. This rivalry and the risk of “strategic manipulation” could lead to the interests of island states being relegated to second place in favour of the strategic interests of foreign powers. The PIS thus fear a disengagement by major powers from existing regional cooperation frameworks in favour of parallel and competing initiatives pursued individually by each donor. This trend risks increasing the fragmentation of aid, limiting coordination among multilateral donors, and compromising the alignment of these initiatives with the priorities and real needs of the PIS.

Paradoxically, the growing interest of major powers in the South Pacific also offers island states the opportunity to benefit from increased cooperation in disaster response, notably through emergency relief operations known as HADR (Humanitarian Assistance and Disaster Relief). These interventions enable them to benefit from logistical and operational capabilities that they do not possess themselves. Historically, the United States (since the 1990s), Australia and France (from the 2010s) have established themselves as leading partners of the Pacific island states, seeking to assert their presence and influence in the region, bilaterally or within multilateral frameworks such as the US-coordinated Pacific Partnership programme. However, for several years China has also stepped up this type of operation, providing humanitarian assistance and logistical support for post-disaster reconstruction efforts. As a result, this “humanitarian aid diplomacy” is increasingly analysed in scientific research as following a logic of power projection, fuelling rivalries and threatening the traditional strategic multi-alignment of the PIS. The differentiated alignment of certain PIS with Western partners, and others with China, thus calls into question the “friends to all” doctrine, insofar as humanitarian-aid partnerships tend to be embedded in broader bilateral cooperation frameworks with each partner, some clauses of which may condition a power’s support on taking distance from another.

How does this rivalry between major powers play out around the issue of climate migration, a central issue for Pacific island states by 2050?

Competition for influence in the South Pacific also manifests itself around the issue of climate migration. Faced with the risk of partial or total uninhabitability of their territories, the PIS are seeking solutions to organise the displacement or relocation of all or part of their populations abroad through the signing of bilateral agreements. Yet these arrangements are not politically neutral: for external powers they constitute an additional opportunity to assert their presence and strategic influence in the region by institutionalising lasting ties through the reception of island nationals on their territory.

To date, the only agreement of this type that has been finalised is the bilateral “Falepili Union” treaty between Australia and Tuvalu, signed in 2024. It provides for the allocation of 280 visas per year to Tuvaluan citizens, allowing them to settle in Australia. While the scheme has attracted strong interest (more than 3,000 Tuvaluans—nearly a third of the country’s population—registered for the first ballot organised in 2025), the programme, given its limited scale, does not represent a major shift in Australia’s policy of admitting island citizens. The agreement, however, also includes notable security provisions. Article 4 notably provides that Tuvalu must consult Australia regarding any future security or defence engagement with third states. This clause, widely interpreted as a mechanism intended to frame, or even restrict, possible future rapprochement with China, thus helps to entrench Australia’s strategic influence over the archipelago and has been strongly criticised locally for its potential impact on Tuvalu’s sovereignty.

In parallel, China is seeking to strengthen its ties with a growing number of South Pacific island states, as illustrated by the agreement signed with the Solomon Islands in 2022. This agreement does not, for the time being, include a migration or climate component, but it illustrates China’s influence strategy in the region, based on deploying a set of cooperation levers (economic, security, diplomatic, cultural). As the effects of climate change intensify, island states may prove more willing to conclude cooperation agreements that could include provisions favourable to China and contribute to extending its presence in the South Pacific, ever closer to French and Australian exclusive economic zones, as we imagined in a recent foresight scenario in a note by the Defence & Climate Observatory. The 2022 agreement was also accompanied by the Solomon Islands’ recognition of the People’s Republic of China’s sovereignty over Taiwan, reflecting China’s desire to disseminate its ideological positions at the regional level.