As climate change drives more intense heatwaves, over 2.4 billion workers, who are regularly exposed to dangerous hot conditions, are already feeling the health impacts of rising temperatures, particularly manual workers in sectors such as construction, agriculture and fisheries.

The World Meteorological Organisation (WMO) and World Health Organisation (WHO) have therefore called on policymakers to guide and protect workers from the impacts of increasing heat stress.

The global agencies also warned that increasing heat episodes are leading to health issues for vulnerable populations in developing countries, such as children, older adults and low-income populations.

The two United Nations bodies raised the alarm in a new report and technical guidance, entitled “Climate change and workplace heat stress”, which relied on five decades of research and evidence, highlighting that the health and productivity of workers are severely impacted by rising temperatures.

Daytime temperatures of over 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.

It highlighted the growing global health challenges posed by extreme heat on workers. The report and guidance outline key issues related with health impacts of extreme heat which include the frequency and intensity of extreme heat events that have risen sharply, increasing risks for both outdoor and indoor workers, worker productivity dropping by two to three per cent for every degree above 20°C and health risks, including heatstroke, dehydration, kidney dysfunction, and neurological disorders, all of which hinder long-term health and economic security.

The report and technical guidance complement findings of the recent International Labour Organisation (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 yearly. According to the study, approximately half the global population suffers adverse consequences of high temperatures.

However, 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.

Some of the recommended actions for governments, employers, and health authorities to mitigate the growing risks of extreme heat on working populations are developing occupational heat-health policies with tailored plans and advisories that consider local weather patterns, specific jobs, and worker vulnerabilities, the need to 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 for first responders, health professionals, employers, and workers to recognise and properly treat heat stress symptoms were also recommended.

WHO’s Assistant Director-General, Health Promotion, Disease Prevention and Care, Dr. Jeremy Farrar, said: “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’s Deputy Secretary-General, Ko Barrett, noted: “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.”

ILO’s Chief of Occupational Safety and Health and the Working Environment, Joaquim Pintado Nunes, explained that the report represents a critical milestone in the collective response to the growing threat of extreme heat in the world of work.