Heat stress: Billions of people are at risk from “invisible killer,” UN warns

Europe and Central Asia show fastest rise

The ILO found that the regions worst affected by excessive heat exposure were Africa (92.9% of its workforce), the Arab States (83.6%), and Asia and the Pacific (74.7%)—all above the global average of 71%. The greatest proportions of excessive heat related work injuries occurred in Africa (7.2% of all occupational injuries) and the Americas (6.7%)

Notably, however, the report found that the Europe and Central Asia region had seen the greatest rise in heat exposure, up by 17.3% between 2000 and 2020—almost double the global average rise of 8.8%. In 2020, 29% of workers in the region were exposed to excessive heat. Additionally, Europe and Central Asia has the second most rapidly increasing proportion of workplace injuries (up by 16.4% between 2000 and 2020), behind only the Americas (up 33.3%).

Recent research published in Nature Medicine estimated that more than 47 000 heat related deaths occurred in Europe in 2023. This was the second deadliest year during the study period of 2015-23, second only to 2022 (61 672 deaths).2

The research paper suggested that the mortality burden would have been as much as 80% higher if current heat strategies, such as public health behavioural advice, were not in place. The authors said that the findings highlighted the “importance of historical and ongoing adaptations in saving lives during recent summers and the urgency for more effective strategies to further reduce the mortality burden of forthcoming hotter summers.”3

In the UK, an estimated 2295 heat related deaths occurred during summer 20234 and almost 3000 in summer 2022, when temperatures exceeded 40°C for the first time. Extreme heat has also affected the UK’s health service, said a parliamentary research report, as heatwaves in 2022 led to surgeries being cancelled largely owing to staff and bed shortages and overheating operating theatres, causing IT systems to fail in three London hospitals.5

Inconsistent legislation

Despite the increasing burden of excess heat on health the ILO said that most countries had inadequate provisions in place to keep workers safe.

An analysis of legislation in 21 countries included in the ILO report found a lack of consistency in how excessive heat was tackled, with countries setting different maximum temperature thresholds and just 33% of legislative measures requiring employers to provide cool, shaded, and ventilated rest areas for staff.1 Less than half of these measures (48%) included health check provision, and only 57% provided rest breaks or modified work schedules to reduce excessive heat exposure.

“Existing strategies to combat heat stress are proving inadequate, especially in the context of rising temperatures and changing weather patterns,” said the ILO report. “Despite the presence of laws and regulations aimed at safeguarding workers from heat stress many of these provisions were established in the past, often with basic requirements that fail to address the complexities of contemporary heat stress challenges.”

The UK currently has no law outlining the minimum or maximum workplace temperatures allowed, although health and safety laws stipulate that employers must keep the temperature at a “comfortable level” and provide “clean and fresh air.”6 Earlier this year MPs said that the UK government was not prepared to deal with the increasing burden of extreme heat and had not grasped the urgency of the problem. Members of the Environmental Audit Committee called on the government to invest in protective measures.7

The BMA has also warned that “decades of underinvestment” mean that NHS buildings are not prepared for rising temperatures and are putting the safety of patients, doctors, and other staff at risk.8

Saving lives and economies

The ILO has now called for countries to introduce comprehensive workplace plans to protect workers from heat, to be applied during all periods of excessive heat and not just during heatwaves. It emphasises that excess heat should be treated as an occupational health and safety hazard and that national legislation is needed to require employers to do risk assessments for all staff and take action to mitigate risks.

Commenting on the report, the UN secretary general, António Guterres, said, “We need measures to protect workers that are grounded in human rights. And we must ensure that laws and regulations reflect the reality of extreme heat today and are enforced.”

The ILO has outlined practical actions employers can take, including ensuring that staff are adequately hydrated, introducing work-rest cycles, providing the correct personal protective equipment, and ensuring that workspaces are well ventilated and cooled. In the longer term employers need to adopt technologies and practices that will help to lower greenhouse gas emissions, such as solar powered cooling systems, energy efficient ventilation, better building insulation, natural cooling strategies, and water recirculation and cooling systems.

“The intensification of excessive heat not only jeopardizes the safety and health of workers, but also undermines the resilience of economies and the potential for decent work on a global scale,” said the ILO report. “While climate-related mitigation efforts will necessitate concerted action over time, workers are being injured and dying now, and therefore heat stress preventative measures should be implemented as a matter of urgency.”