As world leaders gather for COP30 in Belém, Brazil, the question looms: How far have we progressed in addressing the interlinked crises of climate change and health? The Lancet Countdown 2025, released just one month before the summit, suggested the answer is deeply troubling.
The report opens with a stark milestone: in 2024, average annual global temperatures exceeded 1.5°C above preindustrial levels for the first time. Of the 20 indicators tracking health risks and impacts, 12 reached alarming new records in the most recent year of available data. Heatwaves continuously intensify and threatening people’s lives as there were 63% surges since the 1990s. Climate shifts are also accelerating the spread of infectious diseases: the climate-defined transmissions potential of dengue increased by 48.5% for Aedes albopictus and 11.6%for Aedes aegypti between 1951-60 and 2015-24, globally.
Slow progress on essential adaptation measures has left populations dangerously exposed to mounting hazards. At the same time, some political leaders continue to disregard scientific evidence in favor of short-term economic and political gains, and several fossil fuel companies have stalled or rolled back climate commitments. Opportunities for a just, health-centered transition, ranging from renewable energy scale-up to low-carbon health systems and climate-friendly diets, remain underutilized, resulting in millions of preventable deaths each year.
Urgent, decisive action is needed now both to protect populations from the climatic changes already locked in and to prevent future threats that could outstrip the limits of adaptation. There are, however, glimmers of progress. In June 2025, the International Court of Justice issued a landmark Advisory Opinion affirming that states have legal obligations to limit greenhouse gas emissions and can be held responsible, including financially, for failure to do so. As the need for rapid climate action intensifies, delivering a preventive and promotive health transformation will require coordinated commitment across all sectors of society.
Read the full report here.