WHO, WMO issue new report and guidance to protect workers from increasing heat stress

22 August 2025, Geneva –The World Health Organization (WHO) and the World Meteorological Organization (WMO) have published a new joint report and guidance highlighting the growing global health challenges posed by extreme heat on workers.

As climate change drives more frequent and intense heatwaves, many workers who are regularly exposed to dangerous heat conditions are already feeling the health impacts of rising temperatures, in particular, manual workers in sectors such as agriculture, construction and fisheries. Increasing heat episodes are also leading to health issues for vulnerable populations in developing countries, such as children, older adults and low-income populations.

“Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities,” said Dr Jeremy Farrar, WHO Assistant Director-General, Health Promotion, Disease Prevention and Care. “This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality, and build more resilient workforces in a warming world.”

The new report and technical guidance, entitled Climate change and workplace heat stress draws on five decades of research and evidence, highlighting that the health and productivity of workers are severely impacted by rising temperatures. WMO reports that 2024 was the hottest year on record. Daytime temperatures of more than 40°C and even above 50°C are becoming increasingly common, a clear indication that immediate action is needed to address the worsening impact of heat stress on workers worldwide.

“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

The report and guidance outline key issues related to the health impacts of extreme heat.

• The frequency and intensity of extreme heat events have risen sharply, increasing risks for both outdoor and indoor workers.
• Worker productivity drops by 2–3% for every degree above 20°C.
• Health risks include heatstroke, dehydration, kidney dysfunction, and neurological disorders, all of which hinder long-term health and economic security.
• Approximately half the global population suffers adverse consequences of high temperatures.

To tackle these challenges, the report calls for the implementation of occupational heat action plans, tailored to specific industries and regions, and developed in collaboration with employers, workers, unions, and public health experts.

Recommended actions

The guidance lays out a clear path for governments, employers, and health authorities to mitigate the growing risks of extreme heat on working populations. The recommended actions include:

• Develop occupational heat-health policies with tailored plans and advisories that consider local weather patterns, specific jobs, and worker vulnerabilities;
• Focus on vulnerable populations with special attention given to middle-aged and older workers, individuals with chronic health conditions, and those with lower physical fitness who can be more susceptible to the effects of heat stress;
• Education and awareness raising for first responders, health professionals, employers, and workers to recognize and properly treat heat stress symptoms, which are often misdiagnosed;
• Engage all stakeholders from workers and trade unions to health experts and local authorities in the co-creation of heat-health strategies that are locally relevant and widely supported.
• Design solutions that are not only effective but also practical, affordable and environmentally sustainable, ensuring policies can be implemented at scale.
• Embrace innovation by adopting technologies that can help safeguard health while maintaining productivity.
• Support further research and evaluation to strengthen the effectiveness of occupational heat-health measures and ensure maximum protection for workers worldwide.

The report and technical guidance by WHO and WMO complement the findings of the recent International Labour Organization (ILO) reports, which highlight that more than 2.4 billion workers are exposed to excessive heat globally, resulting in over 22.85 million occupational injuries each year.

“This report represents a critical milestone in our collective response to the growing threat of extreme heat in the world of work,” said Joaquim Pintado Nunes, ILO’s Chief of Occupational Safety and Health and the Working Environment. “Aligned with the ILO’s mandate to promote safe and healthy working environments as a fundamental right, it offers robust, evidence-based guidance to help governments, employers and workers confront the escalating risks of climate change. 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.”

Call to action

This guidance serves as a critical resource for policymakers, public health officials, and employers in mitigating the escalating impact of workplace heat stress. It aligns with key United Nations Sustainable Development Goals, calling for decisive actions that protect vulnerable workers, reduce poverty, and promote sustainable economic growth. Immediate implementation of policies and programmes that safeguard worker health and productivity in the face of climate change is essential.

In the context of the accelerating climate crisis, this guidance serves as a vital tool to help countries respond decisively, protecting lives, livelihoods and economies from the growing threat of extreme heat.