In brief
The Lancet Countdown’s 2026 report, released on November 6, 2026, argues that the health risks of climate change have risen faster than in the previous decade, citing 710,000 heat‑related deaths in 2023 alone. Report authors urge the world to declare climate change a global health emergency, highlighting the continued dominance of fossil fuels and recent record investment in clean energy.
On 6 November 2026, a statement issued by the University of Sydney announced that scientists behind the 2026 Lancet Countdown on Health and Climate Change have called for climate change to be declared a global health emergency, citing a sharp uptick in health risks linked to the planet’s warming.
The report, produced by 146 researchers from 71 institutions—including seven from the University of Sydney—found that many climate‑related health risks accelerated in the decade after the 2015 Paris Agreement more quickly than in the preceding decade. It highlighted that heat has become the leading climate‑driven cause of death, with an estimated 540,800 deaths per year on average between 2016 and 2023, about 68 percent attributable to human‑caused climate change.
In 2023, the hottest year of the period, heat was linked to a record 710,000 deaths worldwide, with more than 70 percent attributable to climate change, according to the report, which was led by University College London in strategic collaboration with the World Health Organization.
Beyond mortality figures, the Lancet Countdown also quantified productivity losses, estimating that heat exposure in 2025 could erode 573 billion potential work hours and cost the global economy an estimated 1.07 trillion U.S. dollars in potential income losses.
The report underscored that while global investment in clean‑energy technologies reached a record 2.1 trillion dollars in 2025, fossil fuels still supplied more than 80 percent of the world's electricity. That proportion of fossil‑fuel use was tied to an estimated 2.73 million deaths annually from air pollution, the study noted.
In response to the Lancet Countdown’s findings, experts urge governments, international agencies, and the private sector to accelerate the transition to renewable energy, strengthen public health infrastructure, and enact policies that treat climate change as a public health crisis rather than solely an environmental or economic issue.
While the report emphasizes differential impacts across regions, it also calls for coordinated international action. It points to the need for climate‑resilient health systems, improved surveillance of heat‑related illnesses, and better equity in the distribution of health resources.
The statement released by the University of Sydney highlighted that the cumulative health toll of climate change has now eclipsed that of many longstanding global diseases, providing a clear mandate for policymakers to enact urgent and comprehensive climate‑health measures.
Advocacy groups and health organizations that have followed the Lancet Countdown’s work now seek to amplify the message, framing the declaration of a global health emergency as the impetus for rapid policy change and sustained investment in public health, environmental science, and sustainable energy initiatives.