As global temperatures continue to rise, the effects of climate change are no longer limited to environmental damage. They are increasingly seen as a direct threat to human health.

Rising temperatures have driven 12 of 20 key indicators tracking health threats related to climate change to record levels over the past year, according to the 2025 Lancet Countdown report.

Direct health impacts

Extreme weather events such as heatwaves, floods, and storms are occurring more frequently and becoming more severe, resulting in many casualties and injuries.

Heat-related illnesses, including heatstroke, are increasing, especially among vulnerable groups like the elderly and outdoor workers. Rising temperatures are also expanding the habitats of disease-carrying mosquitoes, which raises the risk of vector-borne diseases such as malaria and dengue fever.  

The report states that higher temperatures have caused a 63 percent rise in heat-related deaths since the 1990s, with an average of 546,000 deaths annually from 2012 to 2021, meaning one person dies every minute because of extreme heat.

Climate change worsens existing health disparities and strains healthcare systems worldwide more than ever. The Lancet Countdown report highlights that ongoing dependence on fossil fuels and insufficient adaptation efforts are fueling this escalating crisis.  

Turning climate action into health opportunities

While the threats are severe, climate action also offers a chance to strengthen health systems and improve public health. Switching to clean energy, for example, can cut air pollution, which is linked to respiratory and heart diseases. Increasing urban green spaces and encouraging active transportation, like walking and biking, can not only lower carbon emissions but also boost physical and mental well-being.  

Furthermore, developing climate-resilient health infrastructure helps communities better prepare for climate-related health emergencies. By incorporating climate adaptation into public health strategies, countries can protect their populations while supporting global climate objectives.  

The Belém Health Action Plan

A key advancement in tackling the health-climate connection is the Belém Health Action Plan, which will be introduced at COP30’s Health Day. The plan seeks to galvanize global efforts to develop climate-resilient and environmentally sustainable health systems.

It calls for adaptation through enhanced climate-informed surveillance and monitoring systems; evidence-based policy and capacity building; and the development and production of innovative, climate-resilient health technologies and supply chains.

It aligns with the WHO's Global Action Plan on Climate Change and Health 2025-2028, which was approved earlier this year at the World Health Assembly. The plan emphasizes integrating health into national and international climate agendas. However, its success will depend on global collaboration and commitment.