--- id: scenarios/tuvalu-and-rising-seas about: label: 'Tuvalu under rising seas: water, land and who stays' description: >- Tuvalu's islands average barely two metres above the sea. Its groundwater is turning salty, new raised land has been built on the capital islet, and since 2025 up to 280 Tuvaluans a year can move to Australia. How much land, water and food will hold those who stay? tags: - Tuvalu - sea level rise - atolls - land reclamation - migration - groundwater scenario: place: 'Tuvalu, centred on Fogafale islet, Funafuti Atoll' since: '2023' scale: community domains: - water - places - people - food - ecology - climate relations: - predicate: example_of target: questions/flooding - predicate: needs target: engines/coastsat provenance: origin: agent sources: - title: >- Tuvalu's Contributions to the Secretary General's Report on Sea-Level Rise (Government of Tuvalu, 2026) url: 'https://sdgs.un.org/sites/default/files/2026-02/Tuvalu.pdf' - title: >- Tuvalu and Partners deliver landmark Coastal Adaptation Project creating new land for the future (UNDP release, via PINA, 16 October 2025) url: >- https://pina.com.fj/2025/10/16/tuvalu-and-partners-deliver-landmark-coastal-adaptation-project-creating-new-land-for-the-future/ - title: 'FP015: Tuvalu Coastal Adaptation Project (TCAP) (Green Climate Fund)' url: 'https://www.greenclimate.fund/project/fp015' - title: >- Chapter 3 - Australia-Tuvalu Falepili Union (Joint Standing Committee on Treaties, Parliament of Australia) url: >- https://aph.gov.au/Parliamentary_Business/Committees/Joint/Treaties/AmendmentstoCITESAppen/Report/Chapter_3_-_Australia-Tuvalu_Falepili_Union - title: >- Mobility provisions in recent Australia-Pacific bilateral agreements (Jane McAdam, Devpolicy Blog, 11 September 2026) url: >- https://devpolicy.org/mobility-provisions-in-recent-australia-pacific-bilateral-agreements-20260911/ - title: >- PACNEWS ONE, 21 April 2026: Tuvaluans get second shot at Australia visa under Falepili pathway url: 'https://islandsbusiness.com/pacnews/pacnews-one-21-april-2026/' - title: >- Tuvalu's traditional development partners and allies: are they doing enough? (Niuone Eliuta, Devpolicy Blog, 19 June 2025) url: >- https://devpolicy.org/tuvalus-traditional-development-partners-and-allies-are-they-doing-enough-20250619/ - title: >- Coral islands defy sea-level rise over the past century: Records from a central Pacific atoll (Kench et al., Geology, 2015) url: >- https://georgehbalazs.com/wp-content/uploads/2019/08/Geology-2015-Kench-515-8.pdf - title: >- Evaluation of Aquifer Salinization in the Atoll Islands by Using Electrical Resistivity (Nakada et al., Journal of the Remote Sensing Society of Japan, 2010) url: 'https://www.jstage.jst.go.jp/article/rssj/30/5/30_5_317/_article' created: '2026-10-23' reviewed: '2026-10-23' reviewed_by: 'Claude, from the sources listed' status: draft --- Tuvalu is nine inhabited islands of coral sand and gravel in the central Pacific, on average barely two metres above the sea.[^1,3,8] In 2026 its government told the United Nations that the freshwater lenses under the islands turn brackish in storm surges and high tides.[^1] Salty soil is cutting the harvest of pulaka, a staple grown in hand-dug pits. Reefs and the fish they support are declining, and several low-lying islets are already permanently under water.[^1] The sea at Funafuti rose about 30 cm over the 60 years before a 2015 study, among the highest rates measured.[^8] That study surveyed 29 Funafuti islands from 1897 to 2013 and found none lost and their total area up 7.3%, because the islands shift and rebuild from reef sand and gravel.[^8] It covers Funafuti only and ends in 2013.[^8] The government's account is more recent and speaks for the whole country, and it reports islets already under water.[^1] Three responses now run side by side. In October 2025 the Tuvalu Coastal Adaptation Project finished 8 hectares of raised land on Fogafale, Funafuti's most populated islet, built to stay above projected sea levels beyond 2100.[^2] Under the Falepili Union treaty, signed with Australia in November 2023, up to 280 Tuvaluans a year drawn by ballot can apply for a permanent visa.[^1,4,5] In 2025, 8,750 people registered for the first ballot, more than half of Tuvalu's citizens;[^5] more than 100 had moved by April 2026, and a second ballot opened in May 2026.[^6] And a 2023 amendment to the constitution holds that Tuvalu stays a state, with fixed sea zones, whatever happens to its land.[^1] ## Who needs an answer - The Government of Tuvalu, deciding where the next raised land goes and who lives on it. It says reclaiming land across all the inhabited islands would cost billions of dollars, far beyond its own revenue.[^1] - The community on Funafuti, whose land-use plan guides what goes on the new ground.[^2] - Whoever manages water, choosing between wells, rain tanks and other supplies as the lenses salt up and rainfall grows less reliable.[^1] - Fisheries officers, since fishing licences were projected to bring in A$33.7 million of the government's A$47.1 million domestic revenue in 2024, and the reefs feed families directly.[^7] - The Australian and Tuvaluan governments and the Tuvaluan community in Australia, who must settle up to 280 people a year. A parliamentary committee heard that the community in Australia may struggle to support that many arrivals without help.[^4] - Funders such as the Green Climate Fund and the Australian, New Zealand and United States governments, deciding what to pay for next, starting with the planned protection of Fogafale's northern shore.[^2,3] ## The domains it chains Sea level, tides and storm waves meet the reef, which supplies the sand and gravel that build and move the islands. Under the islands a thin lens of rainwater floats on salt water, and the pulaka pits and gardens depend on it. Reef fish feed families, and licences for the offshore tuna bring in most of the government's own revenue.[^7] Burial grounds and churches stand on eroding shores. People can stay, move onto raised land, or move to Australia and perhaps come back. ## What a twin should let people try - Water: how much fresh groundwater is left under Fogafale and the outer islands under a given sea level, run of dry years and rate of pumping, and when rain tanks alone fall short. One study traced salt reaching Fogafale's groundwater on spring tides through porous gravel laid down when the airfield was reclaimed,[^9] so a model should ask how new reclaimed land behaves too. - Land: which shores are building up and which are wearing away, and what happens to sand supply when a seawall or new platform is added. - Housing: how many people the 8 new hectares and later phases can house, and what that does to crowding on the rest of Fogafale. - Population: how many people stay on each island over 10 or 30 years at different take-up rates of the Falepili visas, and what that means for schools, clinics, fishing crews and the money sent home. - Money: with fishing licences as the main domestic income, which mix of reclamation, water supply and coastal protection a given budget can buy. ## Where to start The government's [2026 submission to the UN](https://sdgs.un.org/sites/default/files/2026-02/Tuvalu.pdf) sets out what it sees happening and what it wants. The Funafuti study by Kench and colleagues maps shoreline position at 29 islands in six snapshots from 1897 to 2013,[^8] a baseline that [CoastSat](/engines/coastsat/) could extend with Landsat imagery and Sentinel-2 imagery from [Copernicus](/data-sources/copernicus-data-space/). Waves, sand and reef can be modelled with a coastal model such as [Delft3D](/engines/deltares-delft3d/). The [use case on flooding](/questions/flooding/) lists more tools.