Climate change threatens coastal heritage worldwide

Sea levels are increasing at an accelerated rate ^1,2 and this is expected to increase flooding along coastlines worldwide ³ . While cultural and natural heritage sites are among the assets most exposed to this threat ^4,5 , a unified global assessment is currently lacking. Here we assess coastal flood exposure of all nearshore UNESCO World Heritage sites worldwide, under different global warming scenarios. We estimate that for a scenario with current climate mitigation policies and action, by the end of this century around one third of World Heritage Sites could be exposed to floods, corresponding to more than 1.1 million hectares of protected and preserved land. Limiting warming to the 1.5°C Paris agreement target would save 89 heritage sites from being exposed. Large countries are projected to face widespread exposure while smaller nations risk losing entire heritage systems. Combining our findings with the ND-GAIN index ⁶ shows that 32 countries with low adaptive capacity are expected to experience high heritage exposure, especially Small Island Developing States. To safeguard these irreplaceable cultural and natural treasures, it is imperative to scale up heritage adaptation efforts and increase support for vulnerable regions.