WHO and WMO Release First Global Workplace Heat Stress Guidance in Over 50 Years
Published: August 27, 2025
As record-breaking heat puts workers’ health and livelihoods at growing risk, the World Health Organization (WHO) and World Meteorological Organization (WMO) have released new joint guidance on workplace heat stress, the first such global guidance since WHO’s last report on the topic in 1969. The report provides evidence-based recommendations to protect workers from rising temperatures and outlines practical measures to safeguard both health and productivity.
The Global Heat Health Information Network (GHHIN) supported the development of the report, Climate change and workplace heat stress: technical report and guidance, drawing on expertise from its members worldwide and working closely with the Horizon 2020 HEAT-SHIELD project. This collaborative effort ensured that decades of research were translated into clear, practical guidance for decision-makers.
“This is one of the first times that experts in climate change and meteorology have teamed up with occupational health specialists and experts in public health to provide an authoritative picture of what climate projections will mean for future conditions of occupational heat stress around the world” said Joy Shumake-Guillemot, GHHIN co-chair and lead of the WHO-WMO Climate and Health Joint Programme, “This kind of interdisciplinary and interagency cooperation is key to to provide robust and authoritative information.”
The report comes at a critical moment. In 2024, the hottest year ever recorded, more than 2.4 billion workers faced excessive heat exposure. Research shows that productivity drops by an average of 2.3 percent for every degree above 19°C. Heat stress is already contributing to illness, injury, and death in sectors ranging from agriculture and construction to manufacturing, with the greatest toll on vulnerable populations.
“This is both a wake-up call and a roadmap for change,” said the report’s lead editor Andreas Flouris, “Climate change has made heat stress one of the defining workplace hazards of our time.”
The new guidance highlights ten key actions for protecting workers in agriculture, construction, and other heat-exposed sectors:
- Combine exposure prevention and health surveillance to reduce heat stress, manage physiological strain, and prevent both short- and long-term health effects.
- Develop targeted programmes with specific interventions for high-risk workers and workplaces.
- Design comprehensive advisories that account for weather, clothing, work type, intensity, duration, payment methods, and adaptive strategies.
- Prioritize vulnerable populations, including older workers, those with chronic conditions, and individuals with lower physical fitness.
- Strengthen medical awareness and training to improve recognition, treatment, and prevention of heat-related conditions.
- Engage key stakeholders such as employers, workers, unions, occupational health experts, and local authorities.
- Ensure feasibility, viability, and sustainability so policies remain practical, cost-effective, and environmentally sound, with measures covering prevention, acclimatization, monitoring, training, and emergency planning.
- Explore technological solutions that can enhance both safety and productivity.
- Monitor and evaluate effectiveness of policies and advisories to ensure maximum protection.
- Integrate climate action, recognizing that tackling climate change is central to reducing future heat risks.
The last time WHO issued guidance on workplace heat stress, the global workforce was smaller, the climate more stable, and the dangers of extreme heat far less pronounced. Today, billions of people, from construction crews to agricultural and factory workers, are confronting rising temperatures that threaten their health, safety, and livelihoods.
Protecting workers from heat is not only a public health priority but also an economic and social imperative. As the report makes clear, addressing heat stress is essential to protecting food systems, infrastructure, and economies themselves. As WHO, WMO and ILO emphasize, urgent and coordinated action is needed to safeguard lives, livelihoods and dignity, and to ensure economies remain resilient as the climate continues to warm.