Days before the world’s governments gather in Antalya, Türkiye, for the COP31 climate talks, the World Health Organization has put a number on what inaction costs — and what a short list of unglamorous fixes could buy. Implementing six climate and health measures worldwide could prevent an estimated 1.6 million deaths every year, the WHO said in a report released on Wednesday, 4 November.
The six measures are not futuristic. They are heat-health warning systems that tell a city a deadly heatwave is coming; drinking-water and sanitation services built to survive floods and droughts; basic hygiene and handwashing facilities; cleaner fuels and stoves for cooking and heating at home; and fossil-fuel prices that reflect the damage burning them does to people’s health. The WHO’s report, titled “Global Benefits and Costs of Prioritized Actions on Climate Change and Health,” modelled what happens if those six are scaled up globally between now and 2075.
The headline numbers are large enough to sound like rounding errors, so they are worth stating plainly. About 1.6 million deaths prevented a year — roughly one in every 40 deaths worldwide, on the WHO’s modelled projections. About 16.7 billion tonnes of carbon dioxide avoided a year, around 31% of global annual greenhouse-gas emissions excluding land use. About $3.9 trillion a year in economic welfare benefits, plus $5.4 trillion a year in fiscal benefits to governments.
One measure does most of the heavy lifting. Getting fossil-fuel prices right — removing inefficient subsidies and pricing in health damage — is projected to prevent about 1.2 million deaths a year on its own, mostly by cutting air pollution, and to generate the largest share of the fiscal gains. It is also, by a distance, the hardest to pass politically, which is precisely why the WHO put it on the list.
The cheapest win may be the most striking. Heat-health warning systems — forecasts, public alerts, and plans for who checks on whom when temperatures spike — return an estimated $835 in benefits for every dollar invested, the WHO said, by cutting heat-related illness and death. Heat kills quietly, often indoors, often among people who live alone. A warning system is, at heart, a decision to treat a forecast as a public-health intervention.
The WHO is candid about the limits of its own arithmetic. The projections rest on ambitious global implementation scenarios, and the agency acknowledged data gaps and uncertainties in long-term estimates. The report does not say who pays, or on what timetable — the two questions that usually decide whether a COP promise survives contact with a national budget. The scale of that funding gap is the subject of our explainer on the climate adaptation gap, and the WHO has made the same point before: lead poisoning kills 3.5 million people a year, and the agency says we already know how to stop it.
Why this matters. Climate talks tend to be argued in tonnes and degrees. This report reframes them in deaths and hospital bills — and argues that the tools to prevent a large share of climate-related deaths already exist and are affordable. “The climate crisis is also a health crisis,” WHO Director-General Dr Tedros Adhanom Ghebreyesus has said of the findings. Whether COP31 treats it that way is the test the report sets for next week.
