The Tuvalu Coastal Adaptation Project

Tuvalu, one of the world's most climate-vulnerable nations, faces an existential threat from rising seas and increasingly intense storms. With only 25 square kilometres of land spread across nine atolls, and much of it less than a metre above spring tide levels, the country has long lacked the data needed to make informed decisions about where to build, how to protect its coastlines, and how to plan for the future. The Tuvalu Coastal Adaptation Project (TCAP), funded by the Green Climate Fund (GCF), implemented in collaboration with the United Nations Development Programme (UNDP) as an accredited agency to GCF, the Pacific Community (SPC) as the scientific and technical partner, and the Government of Tuvalu, set out to change that.

In 2023, TCAP was handed over to the Government of Tuvalu. This transition marked the delivery of a freely available coastal hazard platform, which is believed to be the first high-resolution, national-scale coastal hazard assessment tool for any atoll country.

The platform brings together inundation modelling, shoreline change monitoring, damage and loss assessments, human activities and marine hazard tools in a single dashboard covering all nine of Tuvalu's atolls. It also draws a national Lidar survey, and physical modelling conducted at the University of New South Wales. The platform directly supports Tuvalu's early warning systems, feeding into a seven-day operational inundation forecast for all communities nationwide.

The Earth Observation (EO) and modelling‑based risk information provided the Government of Tuvalu with a clear, evidence‑based foundation for action. A national training programme was undertaken, building technical capacity among government officials across departments including Lands and Survey, Climate Change and Disaster, and the Environment. For the first time, decision‑makers could confidently prioritise adaptation measures and demonstrate the scale of need to development partners. This directly informed and justified more than USD 45 million in climate adaptation investment, enabling large‑scale coastal protection and land reclamation works to move from ideation into implementation. Importantly, it provided a scientific baseline to inform long term adaptation strategies (LCAP). Furthermore, the same risk evidence was used to inform updates to national building codes, including minimum floor‑level requirements, ensuring new development is resilient to current and future coastal hazards.

Thanks to the scientific achievements of TCAP, the service has now been scaled up to support other Pacific nations, including Niue and the Cook Islands, with Tonga in the pipeline.

Tuvalu, as a low-lying atoll country with very limited land and high exposure to sea level rise, storm surges and coastal inundation, urgently needs practical adaptation solutions. Government and other users need accessible, high-resolution information on shoreline change, inundation, marine hazards, and damage and loss to support coastal protection, early warning systems, and other risk-informed responses. These models and responses are dependent on accurate topographic height above sea level.

The platform was developed to meet this need by combining EO-informed analysis with other scientific inputs in a format that supports decision-making across government, communities and partners. It helps guide choices on where and how to build, plan adaptation measures, strengthen early warning systems, and respond to priorities reflected in Tuvalu’s broader adaptation planning, including the urgent needs identified through its National Adaptation Plan process.

“SPC’s modelling capacity in relation to coastal environments is among the world’s best. It has been fantastic to work with them in delivering this important, state-of-the-art work for Tuvalu,” said UNDP Coastal Adaptation Specialist and Chief Technical Advisor to TCAP, Arthur Webb. “You simply cannot design sound, risk-informed climate change adaptation solutions and long-term strategies without this type of information. This platform provides the required foundation.”

The project deployed several complementary EO-informed data products to address Tuvalu’s coastal information gaps. These included a national-scale coastal flood hazard assessment, shoreline change detection and monitoring, and high-resolution inundation modelling that combined LiDAR elevation data, bathymetry, wave conditions, tides, storm surge and sea-level scenarios. Together, these products helped overcome the lack of location-specific risk information by showing how exposure varies across Tuvalu’s atolls and islands, and by identifying areas vulnerable to erosion, flooding and wave impacts.

A key input was a 40+ year high-resolution wave hindcast for Tuvalu, which improved understanding of the wave climate and long-term trends that drive coastal flooding and shoreline change in atoll environments. This evidence base strengthened the platform’s ability to support practical decisions on coastal protection, infrastructure siting, adaptation planning and early warning. In this way, the project translated EO data and related modelling into usable risk information for government and other stakeholders, as reflected in Wandres et al. (2023) and Wandres et al. (2024).

The platform drew on a combination of Earth observation, survey and modelled data to assess coastal hazards across Tuvalu. Key inputs included the national LiDAR baseline survey completed in 2019, which provided high-resolution elevation data, as well as high-resolution aerial imagery used to examine specific locations and coastal conditions. These were combined with shoreline monitoring data, sea-level information, and storm-wave simulations to assess inundation risk and shoreline change over time.

The analysis also incorporated tide, storm surge, storm size, storm direction, and sea-level variables, with tens of thousands of simulations used to model potential inundation. Because Tuvalu’s islands are surrounded by reef platforms and fringes, physical modelling undertaken at the University of New South Wales’ Manly Hydraulics Laboratory was used to calibrate and strengthen the computer simulations. Together, these datasets provided the evidence base for the platform’s hazard, risk and adaptation information products.

Behind Tuvalu’s powerful plea for recognition at the ICJ, stood SPC’s scientific and technical support. SPC provided the 3D sea-level rise modelling that visualised the future of Tuvalu’s islands, transforming abstract projections into stark imagery of encroaching seas. These models became vital tools for the ICJ process, ensuring that Pacific arguments were grounded in both science and lived experience.

The work gave Tuvalu, for the first time, a publicly available, national-scale platform to understand and plan for coastal risks linked to sea level rise and more intense storms. It strengthened the ability of government, communities and partners to make risk-informed decisions about where to build, how to protect important infrastructure, and how to plan for climate adaptation over time. It also supports early warning and preparedness by, and it also helped turn complex hazard information into more accessible visual tools, including 3D atoll modelling, to support awareness, communication and engagement with decision-makers and wider audiences.

“We warmly welcome this new platform,” said Faatasi Malologa, Director of Lands and Survey. “It is a powerful tool which fundamentally improves our understanding of coastal hazards, helping to inform our development planning and how we adapt to climate change into the future.”

“You see your land changing every day. The wells that fed us are salty. The songs we used to sing about the seasons no longer match the winds. It feels like our history is slipping away with the tide,” expressed Ms Fafetai Namofo, Technical Support Facility (TSF) Officer with the Tuvalu Survival Fund.

The main beneficiaries include the Government of Tuvalu, especially departments such as Lands and Survey and the Tuvalu Meteorological Service, as well as other government agencies, development partners, NGOs, communities, infrastructure planners, and private land users. In other terms, the platform helps protect lives, homes, land and essential services in a country where land is scarce and climate risks are immediate. It also builds local capacity so Tuvaluan institutions can continue using and updating the information to support long-term resilience.