Nature Climate Change research highlights health costs of global warming, with heat exposure driving most fatalities and children facing disproportionate risks

Human-induced climate change is directly responsible for at least 31,119 deaths every year, with associated economic losses valued at up to USD 357.9 billion, according to a new study published in Nature Climate Change.

The research, led by Colin J. Carlson of Yale University, analysed 20 attribution studies that isolate the role of anthropogenic warming in illness, disability and mortality. The findings, the authors said, offer the strongest evidence yet of the present-day health burden of climate change. “After millions of preventable deaths, climate change must be treated like a health emergency,” Carlson said.

Heat exposure emerges as deadliest driver: 
Between 1991 and 2018, nearly 2.72 lakh deaths across 43 countries were linked to heat exposure from human-driven warming. Europe alone saw sharp impacts, with Paris recording over 500 deaths during the 2003 heatwave and Switzerland reporting 370 fatalities in the summer of 2022.

Other extreme events added to the toll. Hurricane Harvey in 2017 caused more than 50 deaths attributed to climate change, while global wildfire smoke between 2010 and 2019 was linked to 1.26 lakh deaths from fine particulate matter.

Children bear a heavy burden:
The study found children face unique and lasting risks. Temperature-related neonatal deaths in 29 low- and middle-income countries totalled 1.75 lakh between 2001 and 2019. In Africa, heat-related child deaths ranged from 3,000 to 11,000 over two decades.

In China, climate-linked preterm births carried annual medical costs exceeding USD 300 million, while associated lifetime earnings losses due to cognitive disabilities were estimated at over USD 1 billion. Climate change also intensified infectious disease risks, including malaria, dengue and diarrhoeal disease, adding thousands of deaths annually.

Despite higher risks in developing regions, most attribution studies remain concentrated in Europe and North America. Carlson urged more investment in researchers from the global South, warning that climate injustice is compounded by knowledge gaps.

Legal and financial dimensions:
Attribution evidence is also shaping climate litigation. A recent preprint found dozens of Swiss heat-related deaths between 1969 and 2018 could be tied to emissions from fossil fuel majors, including Chevron, ExxonMobil and Saudi Aramco, with attributable losses of up to $189 million each. Such findings could influence loss-and-damage negotiations at international forums.

Expanding the evidence base:
The authors stated that existing estimates undercount the true health toll, with limited studies on malnutrition, mental health or displacement. Every additional 1°C of warming is projected to increase food insecurity by up to 2 per cent, yet mortality estimates for hunger remain absent.

“Health impact attribution is the strongest available evidence of what climate change is already doing to human well-being,” Carlson said. “The task now is to expand this research to capture the full scale of global losses.”