WHO warns heat exposure at work is a global emergency

A joint report released by the World Health Organization (WHO) and the World Meteorological Organization (WMO) delivers a stark warning: extreme heat, exacerbated by climate change, poses a growing occupational hazard that endangers health and productivity across the globe.

For the first time since 1969, the WHO has issued a comprehensive report focused solely on workplace heat stress. Its findings reveal that over 2.4 billion workers—around 70% of the global workforce—are routinely exposed to dangerous levels of heat, resulting in nearly 23 million injuries and almost 19,000 deaths annually.

The report also underscores a steep economic toll: for every 1 °C rise above 20 °C, productivity slumps by 2–3%, especially in physically demanding sectors such as agriculture, construction, and fisheries. Health risks span a spectrum—from heatstroke and dehydration to neurological disorders, kidney failure, and cardiovascular disease.

The year 2024 was confirmed as the hottest ever recorded, while the past decade ranks as the warmest on record. Temperatures regularly breach 40 °C in Europe and soar above 50 °C in parts of Africa and the Middle East.

WHO’s Director of Environment, Climate and Health, Rüdiger Krech, emphasises that heat in the workplace is “not just discomfort. It is a real health risk,” noting that sustained core body temperatures above 38 °C can lead to serious heat-related illnesses. WMO Deputy Secretary-General Ko Barrett added that protecting workers from extreme heat is both a health imperative and an economic necessity.

Employers are urged to develop occupational heat action plans, tailored to local climate and job-specific conditions—this means adjusting work schedules, providing cooling zones and hydration, and even using urine colour charts to monitor dehydration. The guidance also calls for education campaigns to raise awareness among workers, health professionals, and first responders.

The report stresses stakeholder collaboration, involving governments, employers, unions, public health officials, and vulnerable worker groups to co-design effective interventions.

During the 2023 European heatwave, Switzerland’s Suva insurance fund recorded a 7% spike in workplace accidents when temperatures exceeded 30 °C—citing impaired concentration and sleep deprivation as contributing factors. In countries such as Italy, governments and unions have responded by enacting decrees to halt outdoor work during peak heat hours.

In Switzerland’s cantons of Geneva and Ticino, construction work was suspended during extreme heat, a move endorsed by trade union Unia, with representatives urging employers to recognise when work becomes “irresponsible” due to heat.

Moreover, schools are also under pressure to adapt. In Germany, the traditional “Hitzefrei” rule allowed early dismissal when temperatures hit 30 °C, but this practice has waned despite the increasing regularity of such conditions. The WHO recommends reconsidering uniform designs and improving ventilation in schools to ensure safe learning environments.

Krech warns that delaying adaptation for budgetary reasons is misguided. Investing in protective infrastructure, he argues, is ultimately more cost-effective than absorbing the health burdens and productivity losses wrought by unmitigated heat exposure.