Overview
- The Lancet Countdown, which published its 10th report on Wednesday, Oct. 28, 2026, finds nearly 3 million heat-related deaths between 2016 and 2023 and a record about 710,000 heat deaths in 2023.
- The study attributes over two thirds of 2023’s heat deaths to human-caused warming using a counterfactual method that subtracts estimated no-warming deaths from reported heat fatalities.
- Researchers estimate recent warming cost the global economy more than $1 trillion per year by reducing worker productivity and hitting GDP hardest in Southeast Asia and Africa.
- The report notes some advances such as 56 WHO member states adapting health systems and $2.1 trillion in clean-energy investment in 2025 but finds large funding and equity gaps with most climate-health research money going to wealthy countries.
- Authors call for a WHO-style international emergency response to coordinate long-term health-focused climate action, warning that falling data availability and geopolitical distraction limit timely policy responses ahead of COP31.