As climate change fuels increasingly intense heatwaves, more than 2.4 billion workers around the world, especially in manual sectors like construction, agriculture, and fishing are facing serious health risks from extreme heat, according to new warnings from the World Meteorological Organization (WMO) and World Health Organization (WHO).
In a joint report and technical guidance titled “Climate Change and Workplace Heat Stress”, the two UN agencies urge governments to take urgent action to protect workers. The report draws on five decades of research and highlights that rising temperatures are already affecting the health, safety, and productivity of workers globally.
Daytime temperatures now regularly exceed 40°C and in some regions, even 50°C posing severe risks not just to outdoor workers but also to those in poorly ventilated indoor environments. Every degree above 20°C can cause a 2–3% drop in worker productivity, while also increasing the likelihood of heatstroke, dehydration, kidney problems, and neurological disorders.
The report also warns that vulnerable populations, including children, older adults, low-income communities, and those with chronic health conditions are disproportionately affected, particularly in developing countries.
The guidance aligns with findings from recent International Labour Organization (ILO) studies, which estimate that extreme heat leads to over 22.85 million work-related injuries annually. It also reinforces the reality that nearly half of the global population is already suffering from the effects of excessive heat.
To address this growing crisis, the agencies recommend:
• Developing occupational heat action plans tailored to specific industries and regions
• Creating heat-health policies based on local weather data and worker vulnerabilities
• Raising awareness among first responders, employers, and workers to recognize and treat symptoms of heat stress
• Protecting vulnerable groups, especially older workers, those with lower fitness levels, and individuals with chronic conditions
WHO Assistant Director-General for Health Promotion, Dr. Jeremy Farrar, noted:
“Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities. This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality, and build more resilient workforces in a warming world.”
WMO Deputy Secretary-General, Ko Barrett, added:
“Occupational heat stress is now a global societal challenge -no longer limited to countries near the equator. Protecting workers from extreme heat is not only a health imperative but an economic necessity.”
ILO’s Chief of Occupational Safety and Health, Joaquim Pintado Nunes, described the report as a critical milestone in the global response to climate-related risks in the workplace.
