In brief
A global report by the Lancet Countdown highlighted that climate‑driven health hazards rose faster after the Paris Agreement, with 710,000 heat‑related deaths in 2023 alone. Despite record clean‑energy investment, fossil fuels still dominate and cause millions of deaths annually, prompting scientists to call for climate change to be declared a global health emergency.
On 6 Nov. 2026, scientists across 71 institutions declared that climate change should be recognized as a global health emergency, citing a surge in heat‑related deaths and other health risks that have accelerated in the decade following the Paris Agreement.
The statement released by the University of Sydney, part of the 2026 Report of the Lancet Countdown on Health and Climate Change, highlighted that many climate‑related health risks grew faster in the decade since 2015 than in the previous decade.
Across 146 researchers, the report estimated an average of 540,800 deaths per year between 2016 and 2023 that were linked to heat, with about 68 percent attributable to human‑caused climate change. In 2023, the hottest year in the period, heat-related deaths reached a record 710,000 worldwide, a figure the report associates with more than 70 percent of those deaths stemming from climate change.
Heat exposure also took a heavy toll on the workforce, with the report estimating 573 billion potential work hours lost in 2025 and $1.07 trillion in potential income losses for affected economies.
While global clean‑energy investment hit a record $2.1 trillion in 2025, the report cautioned that fossil fuels still supplied more than 80 percent of the world's electricity. Pollution from these fuels was linked to an estimated 2.73 million deaths each year, adding a substantial health burden that the scientists argue demands urgent global policy action.
The Lancet Countdown was led by University College London in strategic collaboration with the World Health Organization, underlining the international scope of the findings. According to the report, the acceleration in health risks since the Paris Agreement suggests that the climate crisis is now a direct threat to public health that must be addressed at the highest levels.
Experts argue that declaring climate change a health emergency would mobilize medical, public‑health, and policy communities to strengthen resilience against heatwaves, vector‑borne diseases, and air‑quality issues that are already reaching epidemic proportions in many regions.
In addition to health impacts, the report notes that the loss of work hours and potential income resulting from climate exposure already strains economies worldwide, exacerbating disparities that will deepen without strong mitigation and adaptation measures.
The scientific community, represented in the report by authors from institutions ranging from the University of Sydney to the University College London, calls on governments, international bodies, and the public for comprehensive action to protect populations from the growing health hazards of a warming planet.
For now, the figure of 710,000 heat‑related deaths in 2023 remains a stark reminder of the human cost of climate change, a cost that scientists say will only increase without decisive global intervention.