In brief
The Lancet Countdown 2026 report shows heat deaths rising to a record 710,000 in 2023, with climate change responsible for 68% of them. Fossil fuels still dominate energy supply, causing millions of deaths. Researchers from Sydney and UCL stress urgent designation of a health emergency.
On November 6, 2026, scientists from more than 70 institutions, led by University of Sydney and University College London in partnership with the World Health Organization, announced that climate change should be declared a global health emergency.
The Lancet Countdown 2026 report notes that heat‑related deaths rose to a record 710,000 worldwide in 2023, more than 70% of which were due to human‑caused climate change. Between 2016 and 2023, heat was linked to an average of 540,800 deaths each year, with 68% attributable to climate change.
Health risks from heat also carry economic costs. The report estimates that heat exposure could erase 573 billion potential work hours in 2025 and shave 1.07 trillion U.S. dollars from global income.
Even as global investment in clean energy hit a record $2.1 trillion in 2025, fossil fuels still supplied over 80% of world electricity. Pollution from these fuels is linked to an estimated 2.73 million deaths annually.
The researchers argue that the accelerating health dangers warrant an emergency declaration, urging governments to double down on clean‑energy transition and climate‑adaptation measures.
