A new Lancet Countdown analysis estimates heat was linked to 710,000 deaths worldwide in 2023, while its longer comparison shows a higher annual burden in the years following the Paris Agreement.
The nearly 36% increase compares the average for 2016-23 with 2006-15. The later period began in the year the Paris Agreement took effect and extends through the last year in the report’s heat-mortality series. The 2023 estimate was the largest annual figure in that series. The findings add to coverage of climate-linked mortality, including EconoTimes coverage of modeled heat deaths in European cities.
The totals come from a model, rather than a tally of death records that name heat as the cause. The analysis draws on mortality data from 129 countries and annual estimates from the Global Burden of Disease. To estimate climate change’s contribution, it compares observed conditions with a modeled climate without human-caused warming. The method assumes the relationship between temperature and mortality stays constant over time, so it does not account for adaptation or maladaptation.
The report identifies older adults, women and people with underlying health conditions as especially vulnerable to heat. It also estimates that cleaner air is preventing 323,000 deaths annually in 70 countries where pollution from fossil fuels has fallen.
Helen Clark, former prime minister of New Zealand and chair of the Lancet Countdown Board, said the report points to a gap between evidence and action. “What’s missing is not evidence, but the political will to act on it,” she said.
The report’s authors recommend formally recognizing climate change as a global health emergency and including health considerations in climate decisions. The recognition remains a recommendation, not an adopted declaration.
