In brief
A new Lancet Countdown report released on November 6, 2026, warns that climate‑driven health hazards have accelerated, with a record 710,000 heat‑related deaths in 2023 alone. The report, compiled by researchers from 71 institutions, urges a global health emergency declaration and highlights the ongoing dominance of fossil fuels in global electricity. It also points to significant economic losses from heat exposure and the need for urgent policy action.
On 6 November 2026, an international group of researchers released the 2026 Lancet Countdown report, calling climate change a global health emergency. The report was produced by 146 scientists from 71 institutions, including seven from the University of Sydney, and was led by University College London in partnership with the World Health Organization.
"Experts have called for climate change to be declared a global health emergency, warning that its impacts on human health are accelerating worldwide," said a statement released by the University of Sydney. The statement highlighted sharp increases in heat‑related mortality, with an estimated average of 540,800 deaths per year between 2016 and 2023.
According to the report, climate change is responsible for about 68 percent of those deaths, and 70 percent of the 710,000 heat‑attributed deaths in 2023 were linked to human activity. These figures represent a record in the decade following the Paris Agreement.
Beyond fatalities, the report has quantified the economic toll of heat. It estimates that exposure to extreme heat will result in 573 billion potential work hours lost in 2025, translating into an estimated 1.07 trillion U.S. dollars in potential income losses. That level of loss underscores the urgency of addressing climate‑driven heat events as a public health crisis.
While the report focuses on heat, it also notes that, despite record investment in clean energy, fossil fuels still supply more than 80 percent of global electricity. Pollution from fossil fuels alone is linked to an estimated 2.73 million deaths annually, a figure that the report calls “significant.”
The World Health Organization, which collaborated with University College London on the report, called for a comprehensive approach that includes both mitigation and adaptation. WHO officials emphasized that policy interventions should target the root causes of climate change while protecting vulnerable populations from the immediate health impacts of heat.
In light of these findings, researchers urge that the health community and policymakers treat climate change with the same urgency as a global health emergency. Their message is clear: without decisive action to reduce greenhouse gas emissions, the escalating health risks will continue to claim thousands of lives each year.
The report’s authors also highlighted a stark contrast between the annual growth of clean energy investments—reaching a record $2.1 trillion in 2025—and the continued reliance on fossil fuels. They argue that, for the health sector to thrive, a swift transition to renewable energy sources is essential to prevent further deaths linked to air pollution and heat.
Because the Lancet Countdown’s mandate is to monitor the health impacts of climate change, the research community stresses that future policy makers must incorporate health metrics into environmental decision making. The authors advise that public health budgets be restructured to accommodate climate‑responsive healthcare facilities and heat‑resilient infrastructure.
In sum, the 2026 Lancet Countdown report signals a critical turning point: the health community recognizes climate change not merely as an environmental issue but as a pressing health crisis that demands a global emergency response. The urgency is captured by the record 710,000 heat‑related deaths in 2023 and the ongoing mortality linked to fossil fuel pollution. Addressing these risks will require coordinated action across multiple sectors, with an emphasis on rapid decarbonization and the integration of health considerations into climate policy.