Experts urge 'global health emergency' as climate harms accelerate

As heat deaths, drought and food insecurity accelerate worldwide, nearly 150 researchers from more than 30 countries are calling for climate change to be declared a "global health emergency."

The health and economic toll of planetary heating has risen sharply in the decade since countries signed the Paris climate accord — a landmark deal to stop climate change that was hailed by the World Health Organization (WHO) at the time as "the most important public health agreement of the century."

Yet, climate change was responsible for more than half a million heat deaths in 2023 alone and nearly 3 million since 2016. The area affected by extreme drought, which threatens food and water supplies and raises the risk of disease, grew more than 700% faster than in the decade before. And heat cost the world an estimated $1.07 trillion in lost potential income last year, all according to the annual Lancet Countdown on Health and Climate Change.

"This cannot continue," said Alan Dangour, director of climate and health at Wellcome Trust, one of the world's largest charities, which funded the Lancet report. "We must change course and put the health and well-being of people at the heart of our response to climate change — measuring success not through emissions targets or degrees Celsius but by lives saved and health outcomes improved."

The latest findings from the Lancet study show how rapidly the health risks are growing by comparing this decade to the one before the Paris Agreement was signed.

Heat is the starkest example. Climate change was responsible for 68% of heat-related deaths between 2016 and 2023, up from 55% in the previous decade. The yearly increase in climate-driven heat deaths more than doubled over the same period.

But deaths are only "the tip of the iceberg," said Ollie Jay of the University of Sydney's Heat and Health Research Center. "Except that iceberg is not melting, it's growing every year." Beneath the surface are also heatstroke, lost sleep, and worsening chronic health conditions.

The economic harms are mounting too. Working in extreme heat puts people at risk of heat exhaustion, illness or injury and, ultimately, losing income and livelihoods.

Heat wiped out 573 billion potential working hours in 2025, with farmworkers bearing the brunt. Vulnerable economies in Africa and South-East Asia were hit hardest with losses reaching 5% of GDP, compared with 0.5% in the more developed economies.

"The economic toll is battering vulnerable sectors and communities the hardest," Marina Romanello, executive director of the Lancet Countdown, who is based at University College London, told journalists at a press briefing.

Water extremes are intensifying too. Satellite data show that since 2003, 43% of the world's land has been steadily drying out, while 37% has been getting wetter. Together, that is more than 80% of land shifting to extremes that threaten crops, food supplies, and sanitation.

Drought can leave people without safe drinking water and raises the risk of infectious disease, while floods bring drowning, injury and contaminated water.

Heat waves and droughts pushed nearly 128 million more people into food insecurity in 2024, compared with the 1981–2010 average.

"This isn't a gradual worsening; it's a step change," Romanello said.

To save lives and protect human health, experts are calling for a new WHO instrument to help countries share information, coordinate responses, monitor threats, and disburse funds. The United Nations and its member states would create the mechanism.

The closest existing version of this is the WHO's Public Health Emergency of International Concern mechanism (PHEIC) used during the COVID-19 pandemic and mpox outbreaks. But built with short-term emergencies in mind, it falls short of addressing a complex threat that requires sustained global action across multiple sectors, like climate change.

The world needs a broader approach, "so that we're not responding to emergency after emergency," said Romanello. "We're doing a cohesive long-term response that builds resilience, builds capacities and builds the possibilities of countries to avoid further emergencies."

Romanello told journalists that "we have more than enough proof" that such action does improve health outcomes. "Early warning systems informed by climate, have already seen a reduction in the adverse impacts of these extreme weather events," she said.

The growth in renewable energy has also partly aided a reduction in deaths from fossil fuel air pollution in half of 140 countries assessed since 2016, preventing an estimated 323,000 deaths a year.

And 56 countries now have national plans to adapt their health services for climate impacts, such as heat waves and disease outbreaks, up from just 14 in 2015.

But progress remains too slow, according to the report.

Fossil fuels, the burning of which releases emissions fueling planetary heating as well as other pollutants, still supply more than 80% of the world's energy.

Energy-related emissions hit a record high in 2024. The world's 100 largest oil and gas companies are on track to produce 150% more oil and gas by 2040 than is compatible with limiting warming to 1.5 degrees Celsius (2.7 Fahrenheit). A year ago, that figure was 138%.

Governments continue to fund fossil fuels, with net subsidies doubling since 2016 to $6.2 trillion. In 2024, 10 countries spent more on such subsidies than on their entire health systems.

Yet as fossil fuel prices rise and renewables become cheaper, these polluting technologies are becoming increasingly uneconomical, said Romanello.

Romanello likened new fossil fuel investment to "investing in Blockbuster when you have Netflix," — a bet on an old technology, referring to the once ubiquitous video rental store that failed to adapt to streaming.

Meanwhile, money to help health systems adapt to climate change is scarce. Developing countries estimate they need around $3.3 billion a year for such adaptations, which the Lancet authors say is likely an underestimate. Only about a third of that was committed in 2024. Foreign aid reductions, led by the US and followed by Germany, which made the second-largest cut, are widening the gap.

"This report is a stark warning that climate change is a health emergency," said Helen Clark, former prime minister of New Zealand and chair of the Lancet Countdown's board. "What's missing is not evidence, but the political will to act on it."