Small islands are “sentinels” of climate change impacts. This is particularly true for Réunion Island, a French overseas and European Union Outermost Region in the South West Indian Ocean.
It is home to a rich diversity of terrestrial and marine ecosystems and characterized by a pronounced topography and significant climatic contrasts. The island’s economy relies mainly on vulnerable and exposed sectors (agriculture, tourism, transport, energy supply). Combined with its insularity and geographical isolation, limited local resources, and dependence on external trade, it makes it particularly sensitive. At last, frequent exposure to climate-driven natural hazards, like tropical cyclones, heavy rainfall, flash floods, landslides, droughts and heatwaves, combined with a fragile socio-economic system, amplify this vulnerability.
Navigating the complex challenges of climate change adaptation requires strategies tailored to this local context. A dynamic and functional science-society interface is central to ensure that scientific knowledge feeds policy and planning, and that societal needs and local realities shape research initiatives and outputs. However, building this interface on Réunion Island faces several interconnected challenges.
At the regional scale, Réunion Island’s regional council holds keys responsibilities spanning regional planning, economic development, research and innovation (supported by the European Fund for Regional Development – ERDF), and environmental policy, positioning it as a central actor for amplifying territorial adaptation. However, translating this strategic position into effective climate action requires overcoming significant difficulties inherent to the island’s unique context. Comprehensive expertise is needed not only on past, present, and future climate but also on their cascading effects across vital sectors – including natural hazards, ecosystems, health, resources, economic development, and land planning. To achieve this, key local challenges have to be tackled.
Key local challenges for adaptation
Réunion Island’s unique geography—remote, narrow (75km wide), and highly mountainous (up to 3000m)—poses significant challenges for climate modelling. Standard global climate models operate at coarse resolutions (50-150km), inadequate for capturing the island’s complex terrain and distinct microclimates. Its geographical remoteness also excludes it from keys European climate and climate-impact modelling projects. Consequently, the island is often “invisible” or poorly represented in large-scale studies, leading to critical gaps in data for effective territorial adaptation planning. This scarcity extends beyond climate data themselves, encompassing insufficient observational data for certain parameters (like long-term wave patterns for coastal erosion studies) and a critical lack of readily usable data detailing specific vulnerabilities and potential impacts across the island’s socio-ecosystems.
Paradoxically, strong local scientific research capacity does exist. CNRS and University of La Réunion host the internationally recognized Observatory of Atmospheric Physics (OPAR) as a WMO global station which is part of European research infrastructures ACTRIS, ICOS and IRISCC. Météo-France (MF) Réunion serves a large weather observation network to monitor tropical cyclones and issues warning as the WMO-designated Regional Specialized Meteorological Center (RSMC) for the South-West Indian Ocean. MF also coordinated the first high-resolution (3km) regional climate projections based on CMIP6 (through the BRIO project). Furthermore, numerous research institutions (University of La Réunion, CNRS, CIRAD, BRGM, IRD) conduct vital local research across diverse fields.
While enhancing scientific knowledge remains essential, data limitations should not be perceived as the only barrier to adaptation. With or without climate change, effectively addressing vulnerabilities often encounters significant hurdles related to coordination, knowledge sharing, and collaboration among local actors.