Small Island developing states (SIDS) are facing an escalating public health crisis as climate change increasingly affects the air people breathe, the food they eat, the water they depend on, and their ability to live and work safely. No longer a distant environmental threat, climate change is bringing more frequent and intense heat, droughts, flooding, sea-level rise and extreme weather events, placing vulnerable populations at greater risk.Although SIDS collectively produce less than one per cent of global greenhouse gas emissions, they continue to bear a disproportionate share of the impacts of a changing climate. Their small size, geographic location, remoteness, limited resources and vulnerable economies make them particularly susceptible to sea-level rise, droughts, flooding, extreme heat and increasingly intense weather events.The health implications are especially concerning for two groups at opposite ends of the age spectrum, infants and older adults.Presenting the findings of the 2025 Small Island Developing States Report of the Lancet Countdown on Health and Climate Change, Dr Georgiana Gordon-Strachan, director of the Tropical Metabolism Research Unit (TMRU) at the Caribbean Institute for Health Research (CAIHR), The University of the West Indies (The UWI), Mona, said the increasing exposure of these vulnerable populations to extreme heat should be a major concern for SIDS.“Infants and older adults are particularly vulnerable to extreme heat, and the substantial increase in their exposure raises an alarm about the health consequences and the urgent need for greater attention to protecting these populations,” Dr Gordon-Strachan said. Between 2015 and 2024, infants under one year old experienced an average of 15.8 days of heatwave exposure annually, compared with 2.4 days during the 2000–2009 baseline period. Among adults over 65, exposure increased from an average of three days annually during the baseline period to 15.9 days.Dr Gordon-Strachan said the findings point to the need for SIDS to strengthen climate adaptation measures and invest in solutions that can reduce exposure to extreme heat.“Protecting vulnerable populations will require greater investment in nature-based cooling systems and other interventions that can help communities cope with rising temperatures,” she said.Infants and young children are less able to regulate their body temperature than healthy adults and can become dehydrated and overheated more quickly. Older adults, particularly those living with chronic illnesses, may also face greater risks during extreme heat.Reducing the health impact of climate change requires a combination of government action, community preparedness and individual responsibility.One of the most important measures is the development and expansion of early- warning systems. Health and weather agencies should work together to issue timely heat alerts and provide clear guidance on protecting vulnerable populations.Families and caregivers should ensure that children and older adults remain adequately hydrated during periods of extreme heat. Outdoor activities should be limited during the hottest parts of the day, while schools, childcare centres and senior-care facilities should have access to shaded, cool and well-ventilated spaces.Regular checks should also be made on older adults who live alone or have chronic illnesses. Communities can establish systems to identify vulnerable residents and ensure they receive assistance during heatwaves, hurricanes, floods and other extreme events. Health facilities must also be better prepared. Hospitals, clinics and senior-care institutions should have climate-resilient infrastructure, reliable backup power, adequate water supplies, and emergency plans that address extreme heat and other climate-related hazards.“Older adults must be considered in climate adaptation and emergency preparedness planning, particularly because many are living with existing health conditions that can increase their vulnerability to extreme heat and other climate-related hazards,” Dr Gordon-Strachan said.The health sector can also strengthen climate and disease surveillance. The report found that fewer than half of SIDS have health systems that receive climate and weather information for decision-making.“Health systems need timely and reliable climate and weather information to anticipate and respond to emerging threats. Integrating climate monitoring with health, disaster and disease surveillance can help countries make better decisions and strengthen resilience,” Dr Gordon-Strachan said.Improving air-quality monitoring and public education is another priority. More than 40 million people in SIDS were exposed to daily PM10 concentrations above the World Health Organization guideline between 2019 and 2023. In the Caribbean, Saharan dust events contribute to poor air quality and can worsen respiratory and cardiovascular conditions.Residents should follow air-quality advisories, particularly during dust events, while people with respiratory conditions should follow medical advice and ensure they have access to prescribed medication.Climate change also threatens food security. The report found that increased heatwaves and droughts were associated with an additional 2.7 million people experiencing moderate to severe food insecurity across 26 SIDS.Strengthening local food production, supporting climate-resilient farming, improving water management and protecting marine ecosystems can help safeguard access to nutritious food. This is particularly important for children, whose growth and development depend on adequate nutrition, and older adults, who may be more vulnerable to food insecurity.Nature-based solutions should also form part of the response. Planting trees, expanding urban green spaces and protecting forests can help reduce temperatures, improve air quality and support mental well-being.“Trees and green spaces are not simply environmental assets. They can help cool communities, improve air quality and support mental well-being, making them an important part of the public health response to climate change,” Dr Gordon-Strachan said.The risks to children extend beyond extreme heat. Climate-related disruptions to food production can increase food insecurity, while poor air quality can worsen respiratory conditions. Changes in temperature and rainfall can also affect mosquito-borne diseases.The report found that climate suitability for transmission of dengue fever and chikungunya increased by nine per cent and 17 per cent, respectively, during 2014–2024 compared with 1951–1960.“The effects of climate change on children extend beyond extreme heat. Changing weather patterns can affect food security, air quality and the transmission of infectious diseases, making it important to integrate climate considerations into child health programmes and public health planning,” Dr Gordon-Strachan said.Protecting children requires climate-health measures in schools, childcare facilities and communities. Parents and caregivers should be educated about heat-related illness, air- quality risks and the importance of hydration, while schools should have plans to adjust outdoor activities during extreme heat.For older adults, families and caregivers should regularly check on those who live alone or have chronic illnesses. Communities should also ensure that vulnerable residents receive timely warnings and assistance during climate-related emergencies.“Children and older adults are among those who require particular attention as SIDS strengthen their response to climate change. Protecting health means building resilient health systems, improving early-warning systems, investing in climate adaptation and ensuring that vulnerable populations are not left behind,” Dr Gordon-Strachan said.Ultimately, minimising the public health consequences of climate change will require governments, health professionals, communities, families and individuals to work together.For small island states on the front line of climate change, climate action is not simply about protecting the environment. It is about protecting lives, livelihoods and the future of entire communities.keisha.hill@gleanerjm.com