Authorities and employers should protect the health of workers who are exposed to extreme heat, according to a report by the United Nations. The UN warns that high temperatures are endangering people worldwide with serious health risks.

The World Health Organization (WHO) and the World Meteorological Organization (WMO) are calling for better adaptation strategies to the extreme heat for millions of people.

Heatwaves are linked to heatstroke, dehydration, kidney dysfunction, and neurological disorders, according to the WHO and the WMO.

This is the first time the heat stress report has been updated for the first time since 1969, and highlights how climate change is driving more frequent and intense heatwaves, worsening health risks.

WHO Director for Environment, Climate Change and Health, Ruediger Krech said, "Billions of people are already exposed to dangerous heat at work. In agriculture, construction and other physically demanding sectors, we're seeing a clear rise in heat stroke, dehydration, and long-term kidney and cardiovascular damage due to dangerous working conditions."

"No one should have to risk kidney failure or collapse just to earn their living," added Krech.

"Protecting workers from heat is a matter of life and death. It's not just about temperature, it's about inequality. The poorest workers are on the front lines of the climate crisis."

The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (2023) states that the global average temperature has already risen 1.1°C above pre-industrial levels, and extreme heat events are now twice as likely.

What type of worker

Manual workers in sectors such as agriculture, construction, and fisheries, as well as vulnerable groups including children and older adults in developing countries, face the highest risks.

Agricultural workers often start before sunrise and continue until sunset, particularly during planting or harvest seasons, which can mean 10–14 hour days, sometimes longer in extreme heat, according to International Labour Organization (ILO). 

Standard construction shifts typically last 8-10 hours but can exceed 12 hours outdoors during peak hours, according to Occupational Safety and Health Administration (OSHA).

Fishers face long, physically demanding hours on reflective water surfaces, further increasing heat exposure, according to International Transport Workers' Federation (ITF).

Deaths and illnesses

A study published in 'The Lancet' (2021) noted that the heat exposure has contributed to more than 12,000 deaths annually among outdoor workers in India and Pakistan. 

In Central America and Mexico, coffee and sugarcane plantations report heat-related illnesses during harvest season, with ILO noting several deaths annually due to heatstroke.

What should employers and governments do

The agencies urged the creation of heat action plans tailored to specific regions and industries, developed in consultation with workers, employers, unions, and public health experts.

“Protection of workers from extreme heat is not just a health imperative but an economic necessity,” said WMO Deputy Secretary-General Ko Barrett.

Legal working limits

Legal limits on working temperatures, proposed by unions in some countries, were cited as one possible approach, though measures would vary depending on local conditions.

For instance, in Spain, labour law sets maximum working temperatures for certain outdoor jobs and mandates regular breaks, ensuring employees are not exposed to unsafe heat levels, according to OSHA. 

Similarly, in Japan, heatstroke prevention guidelines recommend shortening shifts when temperatures exceed 31°C wet-bulb globe temperature, particularly in outdoor and physically demanding roles, Japanese Ministry of Health, Labour and Welfare (MHLW) reports.

Consquences of heat stress

The ILO estimates that by 2030, 2% of global working hours per year could be lost due to extreme heat, equivalent to 80 million full-time jobs.

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