Small Island Developing States (SIDS), including those in the Caribbean, are facing a mounting health crisis as climate change accelerates, exposing infants, elderly people and vulnerable communities to more extreme heat, rising food insecurity, worsening air quality and a growing risk of infectious diseases.Those are among the findings of the 2025 Small Island Developing States Report of the Lancet Countdown on Health and Climate Change, launched on Thursday. Produced by 30 authors from 23 institutions, the report examines 28 indicators at the intersection of climate and health, and includes a chapter on the challenges SIDS face in accessing international climate finance.The report highlights the disproportionate burden borne by SIDS, which account for less than 1 per cent of global greenhouse-gas emissions, but remain among the countries most exposed to climate-related threats because of their size, geographic isolation and vulnerability to hurricanes, droughts, floods, sea-level rise and other extreme weather events.Presenting the findings, Dr Georgiana Gordon-Strachan, director of the Tropical Metabolism Research Unit at the Caribbean Institute for Health Research, said the evidence points to an urgent need for stronger health systems, coordinated climate action and greater international support.“Small Island Developing States are on the frontline of climate change. While our contribution to global emissions is minimal, the health consequences for our populations are profound and continue to worsen. The evidence clearly shows that climate change is no longer simply an environmental issue, it is one of the greatest public health challenges facing our region,” she said.Among the report’s starkest findings is the surge in exposure to extreme heat. Between 2015 and 2024, children under the age of one experienced seven times more heatwave exposure than during 2000-2009, with annual exposure rising from an average of 2.4 days to 15.8 days.For adults aged 65 and older, annual heatwave exposure increased more than fivefold, from three days to 15.9 days.Gordon-Strachan noted that both groups are particularly vulnerable to heat-related illnesses.“Heat affects every aspect of our health, from pregnancy and infant development to chronic diseases among older adults. These findings reinforce the need to invest in cooling strategies, urban green spaces and nature-based solutions that can reduce heat exposure while improving overall wellbeing,” she said.Rising temperatures are also making outdoor exercise increasingly difficult. In 2024, SIDS experienced 41 per cent more hours in which temperatures posed a moderate risk of heat stress during light physical activity than in the 1990s.That trend presents an additional challenge for Caribbean countries already grappling with high rates of obesity, diabetes and cardiovascular disease.ECONOMIC COSTSThe report estimates that excessive heat led to the loss of 4.4 billion potential working hours across SIDS in 2024, double the average recorded during the 1990s.Those lost hours translated into an economic cost equivalent to 1.27 per cent of combined GDP, compared with a global average loss of 0.99 per cent.According to Gordon-Strachan, the figures illustrate how climate change affects livelihoods and economic development as well as health.“Many of our workers, including farmers, construction workers, fishers and vendors, spend long hours outdoors. Rising temperatures reduce their ability to work safely, affecting household incomes, food production and economic growth,” she said.Food security is also under growing strain. In 2024, around 80 per cent of land areas across 15 SIDS experienced at least one month of extreme drought, disrupting agricultural production, affecting planting cycles and reducing local food supplies.The report estimates that heatwaves and drought contributed to an additional 2.7 million people experiencing moderate to severe food insecurity across 26 states.Marine ecosystems are also under pressure. Average sea-surface temperatures increased by 0.61°C between the 1981-2010 baseline period and 2022-2024, threatening fisheries that many island communities depend on for food and income.DISEASE RISKSAir quality is another growing concern. More than 40 million people living in SIDS were exposed to PM10 concentrations above World Health Organization guidelines between 2019 and 2023.In the Caribbean, much of that pollution is linked to seasonal Saharan dust events. Exposure increases the risk of asthma, chronic obstructive pulmonary disease, stroke and cardiovascular disease.The report recommends further research into dust early-warning systems to better protect vulnerable populations.At the same time, warmer temperatures are creating more favourable conditions for mosquito-borne diseases. Compared with the 1951-1960 baseline period, climate suitability for dengue transmission increased by 9 per cent during 2014-2024, while suitability for chikungunya transmission rose by 17 per cent.Despite the challenges, the report identifies areas of progress. The lethality of extreme weather events fell by 4 per cent during 2015-2024 compared with the previous decade, suggesting improvements in disaster preparedness and early-warning systems.Yet the number of people affected by such events rose by 195 per cent, reflecting the increasing intensity and reach of climate-related disasters.Only 10 of the world’s 58 SIDS have developed dedicated health and climate adaptation plans, while fewer than half integrate climate and weather information into health-surveillance systems.“This tells us that although progress is being made, much more investment is needed to build climate-resilient health systems capable of anticipating and responding to future risks,” Gordon-Strachan said.The report also points to advances in renewable energy. Solar photovoltaic generating capacity increased 2.3-fold between 2020 and 2024, while annual investment in clean energy exceeded investment in fossil fuels by roughly US$300 million.Researchers argue, however, that substantially greater public and private investment will be needed if SIDS are to meet renewable-energy targets between 2030 and 2050.A chapter on climate finance highlights persistent obstacles to securing international funding, including fragmented application processes, duplicative reporting requirements and limited technical capacity. The report calls for simpler funding mechanisms and stronger support for vulnerable island states.LANDMARK RULINGThe report also highlights the July 23, 2025 advisory opinion of the International Court of Justice, which found that the Paris Agreement’s 1.5°C temperature target is legally binding, ruled that fossil-fuel production might constitute an internationally wrongful act in certain circumstances and affirmed that states could be required to provide reparations where climate-related harm can be established.The case followed years of advocacy by Pacific Island Students Fighting Climate Change, the government of Vanuatu and regional partners.Gordon-Strachan described the ruling as a landmark moment for climate-vulnerable nations.“This decision provides renewed hope for Small Island Developing States. It strengthens the global conversation around accountability, climate justice and the responsibility of all nations to protect the health and future of those who are disproportionately affected by climate change,” she said.She said the report should serve as both a warning and a call to action.“The evidence is overwhelming. Climate change is already affecting the health, livelihoods and future of millions of people living in Small Island Developing States. The challenge before us now is to translate this evidence into meaningful policies, sustained investment and collaborative action that will protect current and future generations,” she said.