Climate change is now a 'global health emergency': Lancet Countdown 2026 report

The Lancet Countdown's 2026 report says climate change should now be treated as a 'global health emergency'. Led by University College London in collaboration with the World Health Organization (WHO), the report finds that a decade after the Paris Agreement, many health indicators linked to climate change are moving in the wrong direction and the harms are accelerating.

The report includes findings from 146 researchers at more than 100 institutions in more than 30 countries.

Researchers found that from 2016, when the Paris Agreement went into effect, through 2023, the latest year with available data, heat was linked on average to more than 540,000 estimated deaths per year. They attribute 68 percent of those fatalities to climate change.

Marina Romanello, a professor at University College London and executive director of the Lancet Countdown, said the numbers point to a clear emergency; heat deaths linked to climate change have reached a record high, and the economic toll is battering vulnerable sectors and communities the hardest.

The past 11 years have been the 11 hottest on record. In 2023, heat could be linked to 710,000 estimated deaths, with more than 71 percent attributable to climate change; researchers say that exceeded the loss of life from malaria or HIV. For 2016 to 2023, nearly 3 million deaths could be connected to climate change.

Heat is also taking a toll on the economy. Because of reduced productivity, researchers estimated that the world lost more than a trillion dollars in potential income in 2025, the third consecutive year losses topped the trillion-dollar mark.

The drought picture is also changing fast. The pace at which land is being hit by extreme drought accelerated by about 700 percent between 2016 and 2025 compared with the decade before the Paris Agreement. In 2025, more than half of the world's land experienced extreme drought for at least a month.

At the same time, land hit by very extreme rainfall rose from 14.8 percent between 2006 and 2015 to 17.2 percent from 2016 to 2025, raising flash-flood risk.

Romanello said that as drought spreads, the world is swinging to water extremes, some places drying out while others flood. This is not a gradual worsening, she said, but a step change that must be recognised as the global health emergency it is.

The report also has positive news. Global investment in clean energy grew by more than 7 percent in 2025 to a record $2.1 trillion, 82 percent more than investment in fossil fuel sources. Renewables grew from 5.5 percent of global electricity generation in 2016 to 13.5 percent in 2023, and cleaner air prevented an estimated 323,000 deaths a year in dozens of countries.

Still, fossil fuels accounted for over 80 percent of global energy supply, and the report says the resulting air pollution is responsible for about 2.7 million deaths worldwide each year.

The authors laid out six priorities for a health-centred response, including the WHO formally recognising climate change as a health emergency and coordinating a global response, making health a core objective of all climate action, cutting greenhouse gas emissions quickly and fairly, creating a shared pool of climate and health data, and wealthier countries providing more grants and low-interest loans.