Heat‑Related Deaths Reach Record 710,000 in 2023, Mostly Linked to Climate Change

The Lancet Countdown analysis, produced with the World Health Organization, estimates that 710,000 people died from heat exposure worldwide in 2023. For the first time, over 70% of those fatalities are directly attributed to human‑driven climate change. The report notes a nearly 36% rise in heat‑related deaths since the Paris Agreement was adopted, underscoring a rapid acceleration of climate‑linked health risks. It also links rising temperatures to a 24% increase in areas suitable for dengue transmission by Aedes albopictus mosquitoes between the 1980s and 2025.

Heat exposure is eroding global productivity as well as health. In 2025, an estimated 573 billion potential work hours were lost to excessive heat, translating into a cost of roughly $1.07 trillion. By contrast, clean‑energy employment grew 2.3% in 2024, nearly double the growth rate of direct fossil‑fuel jobs, suggesting a shift toward lower‑carbon workforces. Cleaner air, driven by reduced fossil‑fuel emissions, is already preventing an estimated 323 000 premature deaths each year across 70 countries. Meanwhile, extreme drought now affects 51.8% of the planet’s land for at least one month, expanding more than 700% faster than during 2006‑2015.

National climate‑health legislation has surged, increasing roughly 50‑fold since 2000, but the distribution is uneven. Wealthy nations account for about 55% of these laws, while developing countries contribute only around 2%. Currently, one in four nations has a formal health‑adaptation plan, up from just 14 members in 2015, and 47 countries have completed vulnerability assessments to guide those plans. The authors call for formal recognition of climate change as a global health emergency to accelerate emissions cuts, expand adaptation financing, and strengthen health‑system resilience ahead of the COP31 summit in Antalya, Türkiye.