Six climate-health actions could prevent 1.6 million deaths each year

WHO's first comprehensive global return analysis covers six priorities: heat-health warnings, climate-resilient drinking water, basic sanitation, handwashing facilities, clean household energy and efficient fossil-fuel pricing. Scaling them could prevent 1.6 million deaths and avoid 16.7 billion tonnes of CO2 each year while producing $3.9 trillion in welfare benefits and $5.4 trillion in fiscal gains. Across five actions with comparable investment data, each $1 is estimated to return $24 on average, with heat-warning systems reaching $835. Results come from modelled 2024–2075 scenarios and remain limited by long-term assumptions and incompletely modelled synergies.