Heat killed more people than malaria in 2023, Lancet researchers call for a global emergency
For the first time, the annual Lancet Countdown report attributes a concrete number of heat deaths to global warming: almost three million between 2016 and 2023.
Extreme heat has become a cause of death on the same scale as HIV and malaria worldwide. That is the conclusion of the tenth edition of the Lancet Countdown on health and climate change, published on Wednesday by the medical journal The Lancet, La Libre and the Dutch Reformatorisch Dagblad report. The report involved 146 researchers from more than thirty countries, led by University College London and produced in collaboration with the World Health Organization, Medical Daily writes.
For 2023, the last year with complete data, the researchers arrive at about 710,000 heat deaths, a record. The Reformatorisch Dagblad sets that against WHO figures for the same year: 630,000 deaths from HIV and 597,000 from malaria. Between 2016 and 2023, an average of more than half a million people a year died from heat, about 36 percent more than in the previous decade. For the first time, the report calculates how many of those deaths would not have occurred without climate change: almost three million over that period, roughly seven in ten. Medical Daily stresses that these are model estimates, not counted deaths.
The consequences go beyond heat. According to the Reformatorisch Dagblad, almost 128 million more people face food insecurity because of heatwaves and drought, and mosquitoes carrying dengue, Zika or chikungunya are reaching areas that used to be too cool for them. There is good news too: thanks to the growth of renewable energy, deaths from air pollution are falling in more than half of all countries. Investment in clean energy hit a record 2.1 trillion dollars in 2025, Medical Daily reports.
The researchers want climate change officially recognised as a global health emergency. Director Marina Romanello said, according to La Libre, that the damage to health is growing faster than the response to it. She proposes a coordinated mechanism modelled on the WHO's approach to pandemics, aimed at a coherent long-term response. The report comes shortly before the COP31 climate summit, which opens on 9 November in Antalya, Turkey.