NEW DELHI: Global warming will cause labour losses most acutely in the tropics and countries like India, China, Pakistan, and Indonesia are expected to experience the largest population-weighted labour and economic losses, according to a new paper published in Nature magazine.
The paper found that every extra degree of global warming will cause greater and greater labour losses, and moving heavy labour to the cooler hours of the day will become less effective as the world warms. It said that heat exposure could be causing chronic kidney disease in otherwise healthy, relatively young workers in Central America, Sri Lanka, India, and Egypt and other areas.
There are physiological limits to the heat/humidity combinations that humans can tolerate. The world currently loses 280-311 billion USD per year due to workers struggling in hot, humid conditions, and if the world gets 2°C hotter than now those losses would rise to 1.6 trillion USD.
Global warming will cause labour losses most acutely in the tropics and subtropics but will also increasingly impact mid-latitudes. Each degree of warming leads to exponential, not linear, losses in labour productivity.
For example, the number of hours lost in the 12-hour workday increases from 101 billion hours per °C in the last 42 years to 197 billion hours per °C with an additional 2°C of global warming.
This is the first study at the global scale assessing how effective it is to move heavy work to the cooler parts of the day as an adaptation to climate change.
Currently, moving labour out of the hottest 3 hours of the day can recoup about 30 per cent of productivity losses. However, this may cause other issues, for example, due to poor sleep during increasingly hot, humid weather.
In the present-day climate, an average summer day in a location like New Delhi, India or Doha, Qatar exposes workers in the shade to midday heat exposure that would cause productivity losses of 15-20 minutes/hour of safe work time. By contrast, in the early morning hours, there are less than 10 minutes/hour of productivity losses.
When labour losses per person are scaled up to the working-age population involved in heavy outdoor labour, India experiences the largest heat exposure impacts on heavy labour (>101 billion hours lost/year) in the world.