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Small Island Developing States (SIDS), including countries across the Caribbean, continue to face an escalating health crisis as climate change intensifies, with infants, older adults and vulnerable communities experiencing unprecedented exposure to extreme heat, worsening food insecurity, declining air quality and increasing risks from infectious diseases.

These findings are contained in the 2025 Small Island Developing States Report of the Lancet Countdown on Health and Climate Change, which was launched on July 16, 2026. The report, a collaborative effort involving 30 authors from 23 institutions, presents evidence from 28 indicators examining the intersection of climate change and health in SIDS. It also includes a dedicated chapter exploring the growing challenges surrounding international climate finance.

The report paints a sobering picture of the disproportionate burden shouldered by Small Island Developing States, which collectively produce less than one per cent of global greenhouse gas emissions yet remain among the countries most vulnerable to climate change because of their small size, geographic isolation, limited economies and exposure to hurricanes, droughts, floods, sea level rise and other extreme weather events.

Presenting the report, Dr. Georgiana Gordon-Strachan, Director of the Tropical Metabolism Research Unit (TMRU) at the Caribbean Institute for Health Research (CAIHR), said the findings underscore the urgent need for coordinated climate action, stronger health systems and increased 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. 

Rising Temperatures Threaten Health

Among the report’s most alarming findings is the dramatic increase in exposure to extreme heat. Between 2015 and 2024, infants under one year of age experienced seven times more exposure to heatwaves than during the baseline period of 2000–2009, increasing from an average of 2.4 days to 15.8 days annually.

Adults aged 65 years and older also experienced a five-fold increase, with annual heatwave exposure rising from 3.0 to 15.9 days.

Dr. Gordon-Strachan noted that these trends are particularly concerning because both age groups are among those most susceptible 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. 

The report also found that rising temperatures are making it increasingly difficult for people to engage safely in physical activity. In 2024, SIDS experienced 41 per cent more hours during which outdoor temperatures posed a moderate risk of heat stress during light exercise compared with the period 1990–1999.

Given that many Caribbean countries continue to battle high rates of obesity, diabetes and cardiovascular disease, reduced opportunities for safe physical activity present another growing public health concern.

Economic Costs Continue to Mount

Climate change is also taking a heavy economic toll. The report estimates that 4.4 billion work hours were potentially lost across SIDS in 2024 because of excessive heat, representing twice the average losses experienced during the 1990s.

These productivity losses translated into an estimated 1.27 per cent of Gross Domestic Product (GDP) across SIDS, significantly higher than the global average loss of 0.99 per cent.

According to Dr Gordon-Strachan, these figures demonstrate that climate change affects not only health outcomes but also livelihoods, economic productivity and national development.

“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 Under Increasing Pressure

Changing weather patterns are also threatening food security throughout Small Island Developing States. During 2024, approximately 80 per cent of the land area across 15 SIDS experienced at least one month of extreme drought.

The prolonged dry conditions disrupted agricultural production, affected planting cycles and reduced local food availability. The report estimates that increased heatwaves and drought conditions contributed to an additional 2.7 million people experiencing moderate to severe food insecurity across 26 SIDS.

Marine ecosystems are equally under pressure. Sea surface temperatures increased by 0.61 degrees Celsius between the baseline period of 1981–2010 and the average for 2022–2024, threatening fisheries that many island communities rely upon for food and income.

Air Pollution and Disease Risks Rising

Air quality also remains a growing concern. More than 40 million people living in SIDS were exposed to PM10 concentrations exceeding World Health Organisation guidelines between 2019 and 2023.

In the Caribbean, much of this pollution is linked to seasonal Saharan dust events. Exposure to poor air quality increases the risk of asthma, chronic obstructive pulmonary disease (COPD), stroke, and cardiovascular illnesses.

The report recommends strengthening research into dust early warning systems to better protect vulnerable populations. Meanwhile, warmer temperatures continue to create favourable conditions for mosquito-borne diseases.

Compared with the 1951–1960 baseline, climate suitability for the transmission of dengue fever increased by nine per cent, while chikungunya transmission suitability increased by 17 per cent during 2014–2024.

Progress in Climate Adaptation

Despite the challenges, the report highlights encouraging signs of progress. The lethality of extreme weather events declined by four per cent during 2015–2024 compared with the previous decade, suggesting improvements in disaster preparedness and early warning systems.

However, the number of people affected by these events increased by 195 per cent, reflecting the growing intensity and reach of climate-related disasters. Only 10 of the 58 SIDS have developed dedicated national health and climate change adaptation plans, while fewer than half currently 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,” Dr. Gordon-Strachan said.

Clean Energy and Climate Finance

The report also points to positive developments in renewable energy. Solar photovoltaic electricity generation capacity increased 2.3-fold between 2020 and 2024, with clean energy investments continuing to outpace fossil fuel investments by approximately US$300 million annually.

Nevertheless, researchers argue that significantly greater public and private investment will be required if SIDS are to meet their renewable energy targets between 2030 and 2050.

A dedicated chapter on climate finance identifies persistent barriers to accessing international funding, including fragmented application processes, duplication of reporting requirements and limited technical capacity within many SIDS.

The report calls for simplified funding mechanisms and stronger support to help vulnerable island states secure the financing needed for adaptation and resilience.

Landmark Legal Victory for Climate Justice

One of the report’s most significant developments is the landmark July 23, 2025, advisory opinion of the International Court of Justice (ICJ). The Court unanimously affirmed that the Paris Agreement’s target of limiting global warming to 1.5 degrees Celsius is legally binding, ruled that fossil fuel production may constitute an internationally wrongful act under certain circumstances and affirmed that states may be required to provide reparations where climate-related harm can be established.

The decision followed years of advocacy led by the Pacific Island Students Fighting Climate Change, the Government of Vanuatu and regional Pacific partners. Dr. Gordon-Strachan described the ruling as a historic moment for 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 added that the report serves 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. 

The 2025 Small Island Developing States Report of the Lancet Countdown on Health and Climate Change provides one of the most comprehensive assessments to date of climate-related health risks facing island nations and offers an evidence-based roadmap for strengthening resilience in some of the world’s most climate-vulnerable countries.