Small Island Developing States under threat by rising seas even in a 1.5 °C warming world

Small Island Developing States (SIDS) have long been recognized as some of the planet’s most vulnerable areas to climate change, notably to rising sea levels and coastal extremes. They have been crucial in raising ambitions to keep global warming below 1.5 °C and in advancing the difficult debate on loss and damage. Still, quantitative estimates of loss and damage for SIDS under different mitigation targets are lacking. This study carries out an assessment of future food risk from slow-onset sea-level rise and episodic sea-level extremes along the coastlines of SIDS worldwide.

The findings show that by the end of this century, without adaptation, climate change would amplify present direct economic damages from coastal flooding by more than 14 times under high-emissions scenarios. Keeping global warming below 1.5 °C could avoid almost half of unmitigated damage but it still will not prevent several SIDS from suffering economic losses that correspond to considerable shares of their GDP. Results underline that investments in adaptation and sustainable development in SIDS are urgently needed, as well as dedicated support to assisting developing countries in responding to loss and damage due to climate change.