By the end of this century, agricultural workers across much of South Asia and parts of Central and South America could face up to 250 days a year of conditions so hot that their bodies cannot sustain meaningful physical labour.
In one of the most comprehensive global assessments of how rising temperatures are reshaping the conditions under which food is grown, the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO) warn that extreme heat has become one of the most serious hazards facing agriculture worldwide, threatening the food security and livelihoods of over a billion people.
The human cost is already mounting. Agricultural workers are 35 times more likely to die from occupational heat exposure than workers in any other sector, and extreme heat is already causing 470 billion working hours to be lost globally each year.
A report defines extreme heat as the point at which temperature thresholds are exceeded in ways that cause moderate or greater physiological stress, or direct physical damage, to crops, livestock, fish and workers.
It describes extreme heat as a contextual, impact-based concept, noting that this creates methodological challenges — particularly for crops, where research has often focused on identifying temperature thresholds for yield loss rather than on heat events as a whole.It also brings up the concept of “thermal safety margin” — the gap between the highest temperatures a species normally encounters and the point at which those temperatures begin to cause damage. As average temperatures rise, this margin narrows. The closer temperatures move towards a species’ damage threshold, the less it takes to push it beyond its limits, like a shorter heatwave or even a slightly hotter afternoon.
“Thus, it becomes increasingly easy for extreme heat events (of decreasing magnitude) to breach the damage threshold,” the report notes.Reports by the Intergovernmental Panel on Climate Change (IPCC) have already warned that, compared with 1.5 degrees Celsius (°C) of warming, the intensity of extreme heat is likely to increase by at least 100 per cent at 2°C and by 300 per cent at 3°C.
This a trajectory that would push more species, landscapes and farming systems beyond the thresholds they can withstand.Drawing on the latest climate observations and agrifood systems research, the report examines risks that have often been under-recognised in climate and development planning. It highlights not only the direct damage caused by extreme heat but also its role as what FAO Director-General Qu Dongyu described as “a major risk multiplier”, placing additional pressure on crops, livestock, fisheries, forests, and the communities and economies that depend on them.
Around one billion people work in agriculture globally, accounting for approximately 28 per cent of the employed population, according to estimates by the International Labour Organization (ILO). Of these, about 450 million are waged workers, many dependent on plantation-based incomes.The burden of extreme heat falls disproportionately on the poorest. In countries with the lowest human development scores, 87 per cent of all lost labour hours are concentrated in agriculture.Women face an additional layer of risk.
Female agricultural workers, often paid by output, frequently restrict their water intake and delay urination due to a lack of sanitation in the fields. This pattern was directly linked by the report to increased rates of chronic kidney disease.These pressures are particularly acute in India. The Indo-Gangetic Plain (IGP) in India spans Punjab, Haryana, Uttar Pradesh, Bihar and West Bengal, and producing the bulk of the country’s wheat and rice, and lies at the epicentre of what the report identifies as one of the world’s most heat-affected and vulnerable agricultural regions
(Cou tesy: DTE)