A new study has shown that a mix of heat and humidity that makes outdoor labour difficult and dangerous is causing over 677 billion lost working hours a year around the world.
The study, which was undertaken by researchers in the United States, estimated the current cost at $2.1 trillion every year, noting that the negative effects of stifling temperatures on people doing heavy work in agriculture and construction had been underestimated.
The latest figures come amid a growing focus on the severe health impacts of climate change, not just as projections of future harm from heatwaves and other extreme events, but also as consequences already playing out across a warming world.
The study, which was published in the journal Environmental Research Letters, looked at data on humid heat—particularly dangerous because the body is less able to cool down by sweating.
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The researchers estimated the number of workers exposed to unsafe levels over the 20 years to 2020, as well as the impact on labour compared to the period 1981 to 2000. They also incorporated the findings from laboratory-based research published last year that suggest productivity drops off at lower temperature and humidity levels than previously thought.
Furthermore, they found that between 2001 and 2020, exposure to high humidity and heat was linked to approximately 677 billion lost working hours a year in heavy outdoor labour.
The study suggested that about three-quarters of the global working-age population is already living in locations where background climate conditions are associated with about a hundred hours of heat-associated lost work per person per year.
Lead researcher of the study, Luke Parsons of Duke University, said that “If outdoor workers are losing productivity at these lower temperature and humidity levels, then labour losses in the tropics could be as high as 500 to 600 hours per person per year, which is over twice as high as previous estimates”.
The study also found that India currently loses around 259 billion hours annually due to the impacts of humid heat on labour, while China loses 72 billion hours and Bangladesh loses 32 billion hours.
It also estimated that climate change is to blame for an additional 25 billion working hours lost annually in India over the last 20 years compared to the previous 20 years, and an extra four billion hours a year in China over the same period.
This story was adapted from france24.
