The 2026 report of the Lancet Countdown on health and climate change was published on 28 October 2026, ahead of the COP31 UN climate conference. It is the tenth annual report, produced by an international collaboration led by University College London (UCL) in strategic collaboration with the World Health Organization (WHO), and it tracks 54 indicators linking climate change and health.
According to WHO's summary, annual average heat-related deaths rose by nearly 36% in the years after the Paris Agreement compared with the previous decade. In 2023 alone, heat was linked to a record 710,000 deaths worldwide, and the report attributes more than 70% of that burden to climate change. UCL reports that extreme drought affected nearly 52% of the world's land for at least a month in 2025, the second-highest level on record.
The report also records progress: global investment in clean energy reached a record US$2.1 trillion in 2025, and WHO notes wider adoption of national health adaptation plans and climate-informed early warning systems. The authors call for climate change to be formally recognised as a global health emergency, with health placed at the centre of climate decisions. The report brings together the work of 146 researchers from more than 100 institutions in over 30 countries.