Labour productivity could fall as low as 40 per cent in countries like India and Pakistan by the end of the century due to climate change, threatening global food production, according to a study.
The research, published in the journal Global Change Biology, predicts that other regions in Southeast and South Asia, West and Central Africa, and northern South America are expected to see physical work capacity reduced to 70 per cent.
"Assessments consistently conclude that climate change will reduce crop yields making food security challenges worse," said study lead Gerald Nelson, a professor at the University of Illinois, US.
"But it's not only crops and livestock that are affected. The agricultural workers who plant, till, and harvest much of the food we need will also suffer due to heat exposure, reducing their ability to undertake work in the field,” Nelson said.
The study involved using computational models to predict the physical work capacity (PWC)—defined as "an individual's work capacity relative to an environment without any heat stress"—under different predicted climate change scenarios.
The models, developed by Loughborough University, UK, are based on data from more than 700 heat stress trials—which involved observing people working in a wide range of temperatures and humidities, and differing weather conditions, including sunshine and wind.
The maximum work capacity achievable by individuals in a cool climate was used as the benchmark for the study—representing 100 per cent physical work capacity, the researchers said.
Reductions in capacity mean people are limited in what they can physically do, even if they are motivated to work. This may translate as farmers needing extra workers to do the same job, or if these are not available, then reducing their crop sizes, they said.
The study shows that agricultural workers are already feeling the heat, with half the world's cropland farmers estimated to be working below 86 per cent capacity in "recent past" (1991–2010) climate conditions.
The researchers also considered potential adaptations to mitigate the impact of climate change on agricultural workers.
Switching to nighttime or shade work to reduce direct solar radiation, was shown to lead to a 5–10 per cent improvement in worker productivity, they said.
A second option is to increase the global use of mechanical machinery and equipment, particularly in Sub-Saharan Africa, where agricultural practices largely involve hard physical labor, according to the researchers.
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