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Health risks driven by climate change, including rising temperatures and severe drought, have increased significantly over the past decade, according to the 2026 Lancet Countdown report published by the medical journal The Lancet.

Compiled under the leadership of University College London in collaboration with the World Health Organization (WHO) and involving 146 researchers from more than 100 institutions, the report calls for a global health emergency to be declared and urges governments to fund health protection.

Heat-related deaths attributed to climate change

The report says climate-related health risks have accelerated since the 2015 Paris Climate Agreement, despite progress made in the intervening years. It argues that the effects of the climate crisis have climbed worldwide over the past decade and calls for the situation to be recognized as a global health emergency.

Between 2016 and 2023, extreme heat was estimated to have caused an average of more than 540,000 deaths worldwide each year, with 68 percent of those deaths attributed directly to climate change. In 2023 alone, deaths linked to extreme heat reached roughly 710,000, and more than 71 percent of them were traced to the effects of climate change, the report found.

The authors say political authorities must prioritize protecting health and provide the necessary financial resources, pointing to a wide gap between what health protection requires and the funds actually allocated to it.

Drought and economic losses

Lost labor and production caused by extreme heat resulted in more than $1 trillion in potential income losses worldwide in 2025, according to the report's calculations.

More than half of the world's land area experienced severe drought for at least one month in 2025, the report records.

Fossil fuels still dominate energy supply

Global clean energy investment reached $2.1 trillion in 2025, a positive development the report notes, but fossil fuels continue to supply more than 80 percent of the world's energy.

The researchers call on international institutions and governments to give priority to climate-driven health risks, speed up cuts in carbon emissions and strengthen global cooperation.

Calls for a health emergency declaration

Marina Romanello, executive director of the Lancet Countdown, said the findings are clear. "The harm climate change is doing to health is growing much faster than the measures the world is developing to counter it, and in many areas it is even gaining pace," Romanello said, describing the shift as fundamental rather than gradual and one that should be accepted as a global health emergency.

The report comes after calls have mounted in recent months for the WHO to declare a health emergency because of the climate crisis.

Key takeaways

• The 2026 Lancet Countdown report calls for a global health emergency over climate-linked health risks.
• Extreme heat was linked to more than 540,000 deaths a year on average from 2016 to 2023, with 68 percent attributed to climate change.
• Heat-related losses in labor and production topped $1 trillion in potential income worldwide in 2025.
• Fossil fuels still cover more than 80 percent of global energy supply, despite $2.1 trillion in clean energy investment in 2025.