A new joint report by the World Health Organization (WHO) and World Meteorological Organization (WMO) has warned that vulnerable groups in developing countries - including children, older adults, and low-income communities - face increasing dangers from more extreme and frequent heatwaves.
The new 96-page joint report Climate change and workplace heat stress published in August 2025 emphasises on the mounting risks as climate change fuels longer, more extreme, and more frequent heatwaves.
Stressing that workers in agriculture, construction and fisheries are already suffering the impacts of dangerous temperatures, the report points out that “Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities.”
WHO Assistant Director-General for health promotion, disease prevention and care Dr Jeremy Farrar said, “This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality, and build more resilient workforces in a warming world.”
WMO confirmed that 2024 was the hottest year on record at 1.55 degrees Celsius above pre-industrial temperatures and with daytime highs above 40 °C becoming commonplace – and in some areas, even exceeding 50 °C.
WMO deputy secretary-general Ko Barrett said, “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. Protection of workers from extreme heat is not just a health imperative but an economic necessity.”
The report details how extreme heat is reshaping the world of work. It finds that worker productivity drops by 2 to 3 per cent for every degree above 20°C.
The health consequences are wide-ranging, including heatstroke, dehydration, kidney dysfunction, and neurological disorders. Overall, nearly half of the world’s population is now experiencing negative effects from high temperatures.
Calling for urgent occupational heat action plans tailored to industries and regions, WHO and WMO guidance includes several recommendations:
- Develop targeted occupational heat-health policies based on local weather and workforce vulnerabilities.
- Prioritize protections for middle-aged and older workers, those with chronic health conditions, and individuals with lower physical fitness.
- Train health professionals, employers, and workers to recognize and treat heat stress, which is often misdiagnosed.
- Involve workers, unions, and local authorities in shaping heat-health strategies.
- Promote affordable, sustainable, and scalable solutions, alongside innovation and new technologies.
- Strengthen research and monitoring to ensure measures remain effective.
The guidance builds on International Labour Organization (ILO) findings that more than 2.4bn workers are exposed to excessive heat globally, resulting in over 22.85m occupational injuries each year.