Key findings:
- Climate change impacts are disproportionately severe in SIDS compared to global averages, despite their minimal contribution to greenhouse gas emissions
- SIDS tend to be highly dependent on food imports, making them vulnerable to climate and international shocks, affecting food production and supply chains
- In 2024, SIDS lost the equivalent of 1.27% of GDP due to reduced labour capacity, higher than the global figure of 0.99%, and experienced an increase in heat-related mortality costs by 432% since the early 2000s, the steepest increase of any group
- In 2023, an additional 2.7 million people (4.9% of the total population in 26 countries considered) were estimated to have experienced moderate or severe food insecurity due to a higher frequency of heatwaves and droughts
- People with low levels of income have a significantly higher risk of suffering from food insecurity relative to those with medium-incomes
- Countries that are relatively more dependent on food imports are at a higher risk of food insecurity
- Climate shocks, which damage infrastructure and disrupt import trade, have a higher impact on more food-import-dependent countries
Small Island Developing States (SIDS) are among the most exposed to climate impacts – whether these be sea level rise, droughts, floods, or extreme events – yet contribute less than 1% to global emissions. A contrast that has seen them become both frontline victims and powerful advocates for stronger climate action.
The new 2025 Small Island Developing States report of the Lancet Countdown on health and climate change sheds light on the status of SIDS and the progress towards achieving the goals of the Paris Agreement by looking at the numbers behind specific indicators that track the relationship between health and climate change in SIDS.
One of these indicators, led by CMCC researcher Shouro Dasgupta and Professor Elizabeth Robinson of the Grantham Research Institute, LSE, tracks the impact of higher frequency of heatwaves and droughts on access to food and quantifies the number of people in SIDS who have become food insecure due to climate change.
"We combined FAO data with heatwave-day and drought-month anomalies compared to the 1981–2010 baseline," says Shouro. "The use of this empirical methodology allowed us to examine whether the relationship between climate change and food insecurity has evolved over time."
The headline finding is that in 2023 an additional 2.7 million people (4.9% of their combined population) across 26 SIDS, which include some of the world's smallest and most vulnerable countries from the Atlantic, Indian Ocean, and South China Sea, the Caribbean, and the Pacific for a combined total population of around 70 million people, experienced moderate or severe food insecurity due to the higher frequency of heatwaves and droughts.
According to the report, a higher number of heatwave days was associated with 5.74% higher moderate or severe food insecurity in 2023; while increasing frequency of droughts was associated with 3.53% higher food insecurity.
The report strengthens the evidence-base for some of the most vulnerable countries and should be situated alongside the idea that the 1.5°C target is legally binding, that fossil-fuel production may constitute an internationally wrongful act, and that a duty to make reparations can arise where causation is established.
Climate Insight for Global Impact
The CMCC Foundation – Euro-Mediterranean Centre on Climate Change (CMCC) is an international, independent research centre that provides state-of-the-art climate science for adaptation and mitigation strategies. By combining climate modelling with economic and impact analysis, CMCC delivers the knowledge, data and analyses that policymakers, businesses and communities need to make science-based decisions on climate change – from the global to the local scale.
