Heat stress and UK food imports from the Mediterranean

Agricultural workers worst impacted

The International Labour Organisation calculated, in 2019, that, by 2030, heat stress would cut working hours globally by 2.2%, costing $2.4 trillion in GDP – a rise from $280 billion in 1995. More recently, in 2024, the ILO estimated that 71% of the global workforce is exposed to excessive heat, with that proportion rising to 74.7% in Asia, 83.6% in the Arab states, and 92.9% in Africa.

Studies presented in the 2025 report of the Lancet Countdown on health and climate change have looked at the growing impacts from heat stress, around the world, including on workers and productivity. Those working outdoors are worst affected, unable to take advantage of building cooling methods, and often with limited shade in increasingly extreme levels of heat.

Freyberg et al (Ruby Coast Research Centre) looked at the working hours lost to heat stress over time in countries around the world. In 2024, around 1.5 billion people worldwide – a quarter (25.3%) of the working-age population – worked outdoors.

Agricultural workers are by far the group most exposed to heat stress. Globally, according to Freyberg et al, they account for nearly two-thirds (63.5%) of all potential work hours lost.

This rises to exactly two thirds in medium Human Development Index (HDI) countries, and three quarters (75.5%) in low HDI countries. This compares to construction workers, who account for 17.7%, service workers (10%), and manufacturing workers (8.8%).