WHO, WMO Warn of Rising Worker Risks from Extreme Heat
A new joint report finds billions of workers face serious health and productivity threats from climate-driven heat stress, urging urgent action to protect vulnerable populations.
- By Stasia DeMarco
- Aug 22, 2025
The World Health Organization and the World Meteorological Organization are warning that extreme heat fueled by climate change is posing an escalating threat to workers’ health and productivity around the globe.
A new joint report, Climate Change and Workplace Heat Stress, draws on five decades of research to show how rising temperatures are already harming billions of workers, particularly those in agriculture, construction and fisheries. Vulnerable groups — including children, older adults and low-income populations — are also increasingly at risk.
“Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities,” said Dr. Jeremy Farrar, WHO’s assistant director-general for health promotion. “This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality and build more resilient workforces in a warming world.”
The report highlights that productivity falls by 2–3% for every degree above 68°F (20°C). Health impacts include heatstroke, dehydration, kidney damage and neurological disorders, all of which threaten long-term well-being and economic security. WMO noted that 2024 was the hottest year on record, with daytime highs topping 104°F (40°C) and even 122°F (50°C) in some regions.
“Occupational heat stress has become a global societal challenge, which is no longer confined to countries located close to the equator — as highlighted by the recent heatwave in Europe,” said WMO Deputy Secretary-General Ko Barrett. “Protection of workers from extreme heat is not just a health imperative but an economic necessity.”
Key Findings
-
Extreme heat events are more frequent and intense, threatening both outdoor and indoor workers.
-
Roughly half the world’s population faces adverse consequences from high temperatures.
-
An estimated 2.4 billion workers are exposed to excessive heat globally, leading to more than 22.8 million occupational injuries annually, according to the International Labour Organization.
Recommended Actions
The guidance urges governments, employers and health authorities to:
-
Develop occupational heat-health policies tailored to local weather and job conditions.
-
Focus protections on vulnerable groups, including older workers and those with chronic conditions.
-
Raise awareness among health professionals, employers and workers to recognize and treat heat stress.
-
Engage unions, workers, experts and local authorities in co-creating heat-health strategies.
-
Promote practical, affordable, sustainable solutions and embrace new technology.
-
Support further research to improve prevention and protection measures.
ILO safety chief Joaquim Pintado Nunes said the WHO-WMO report marks a “critical milestone” in global efforts to confront climate-driven workplace hazards. “Together with WHO and WMO, we call for urgent, coordinated action to safeguard the health, safety and dignity of the more than 2.4 billion workers exposed to excessive heat worldwide,” he said.
The report aligns with the U.N.’s Sustainable Development Goals, calling for immediate policies to shield workers and ensure sustainable economic growth as climate risks accelerate.