Climate change health harms are accelerating, global report warns

The 2026 Lancet Countdown on Health and Climate Change reports that many climate-related health harms are increasing faster than the global response to address them. The report was produced by 146 researchers from more than 100 institutions across over 30 countries, led by University College London, in strategic collaboration with the World Health Organization (WHO).

Rising heat and drought risks

According to the report, annual average heat-related deaths increased by nearly 36% in the years following the Paris Agreement entering into force compared with the previous decade. In 2023 alone, heat was linked to a record 710,000 deaths globally. The researchers found that more than 70% of that burden was attributable to human-caused climate change.

The report also highlights worsening drought conditions, increasing exposure to hydrological extremes, and substantial economic losses linked to heat exposure. Dr Diarmid Campbell-Lendrum, Head of the Climate Change, Air Quality and Energy and Health Unit at WHO, said: “Climate change is already harming health in every region of the world, and the evidence shows that many of these impacts are accelerating.”

Clean energy progress saves lives

Despite the growing risks, the report points to important progress. Global investment in clean energy reached a record US$2.1 trillion in 2025. Many countries that have lowered air pollution from fossil fuels are estimated to be protecting thousands of people from premature deaths each year.

Countries are also making advances in building health systems that can withstand climate shocks. These include increased adoption of national health adaptation plans and early warning systems informed by climate data. “This report demonstrates that climate action is a health intervention,” Dr Campbell-Lendrum added. “Cleaner energy, stronger health systems and early warning systems are saving lives today.”

A call for emergency action

The report's authors call for climate change to be formally recognized and addressed as a global health emergency. They recommend integrating health considerations into decisions about reducing emissions, adapting to climate shifts and financing climate projects.

WHO is responding through surveillance, technical guidance and emergency operations. Since September, WHO has been mobilizing expertise and support to countries most at risk from the expected health impacts of the ongoing El Niño weather pattern. Under international health rules, public health emergencies driven by climate change may qualify for a coordinated international response.

While this report describes global trends, its findings apply to all regions. People everywhere face changing weather patterns that affect daily health. Understanding these risks helps communities prepare and stay safe.