Rising heat stress is putting crops, livestock and agricultural workers under growing pressure, but early warnings and better adaptation could help limit losses.
Extreme heat is emerging as one of the most serious threats facing agriculture worldwide, with African farmers and agricultural workers among those likely to face rapidly increasing risks, according to a joint report by the Food and Agriculture Organization of the United Nations (FAO) and the World Meteorological Organization (WMO).
The report, Extreme Heat and Agriculture, finds that rising temperatures are already affecting crops, livestock, fisheries and forests, while reducing the health, productivity and working capacity of people whose livelihoods depend on agriculture.
FAO and WMO describe extreme heat as a “risk multiplier” because it can intensify other hazards, particularly drought and water shortages, creating compound impacts that threaten both agricultural production and rural livelihoods.
African workers face growing heat exposure
One of the report’s most significant findings concerns agricultural workers in Africa.
A forthcoming FAO study cited in the report projects sharp increases in the number of agricultural workers exposed to extreme heat over the coming decades.
In West Africa, the number of workers exposed to extreme heat for most of the June-to-August cropping season could increase by 78 per cent by mid-century under a high greenhouse-gas concentration pathway compared with the current baseline.
In East Southern Africa, exposure during the December-to-February cropping season is projected to rise by 83 per cent.
Central Africa faces an even steeper increase, with the number of agricultural workers exposed to extreme heat projected to more than double, rising by more than 118 per cent.
The report says population growth and increases in the number of farm workers account for only a small part of these increases, with accelerating climate change driving most of the projected rise.
Heat is already affecting farm productivity
The impacts are not only a future concern as the FAO-WMO assessment finds that extreme heat is already causing significant productivity losses. Yields of staple crops such as maize and wheat have declined by about 7.5 per cent and 6 per cent respectively for every 1°C of warming, with further losses projected as temperatures rise.
Livestock are also vulnerable. Under a high-emissions scenario, nearly half of the world’s cattle could face dangerous heat exposure by 2100, with annual losses approaching US$40 billion in 2005 dollars. Under a low-emissions pathway, however, the report says livestock impacts could be reduced by nearly two-thirds.
For agricultural workers, the outlook is similarly concerning. Under a 3°C warming scenario, the combined measure of labour supply and productivity could decline by approximately 33 per cent in Africa, compared with 25 percent in Asia and 17 percent in the Americas.
Early action can help farmers adapt
The report emphasizes that farmers are not without options.
Because extreme heat can often be forecast, stronger climate services and early warning systems can give farmers time to prepare.
Anticipatory measures can include securing water and livestock feed ahead of a heatwave, helping reduce animal deaths and preventing farmers from resorting to damaging coping strategies such as selling productive assets.
Other adaptation measures include heat-tolerant crop varieties and livestock breeds, improved soil and water management, irrigation, shade for livestock and changes to planting or feeding times.
Farmers can also adjust planting dates to avoid the hottest periods of crop development, while livestock can be fed during cooler parts of the day.
Such decisions are more effective when farmers have access to agrometeorological advisories and seasonal forecasts.
Protecting agricultural workers will also require practical measures such as drinking water, shade, rest breaks and adjustments to working hours during extreme heat.
A narrowing window to prepare
FAO and WMO warn that adaptation has limits. While better farming practices, early warning systems, climate services and investment can reduce vulnerability, the report stresses that long-term action to reduce greenhouse-gas emissions remains essential.
For Africa’s farmers, the message is clear: extreme heat is already changing the conditions under which food is produced.
Ensuring farmers and agricultural workers receive timely climate information, appropriate technologies and financial support could help protect both livelihoods and food supplies as temperatures continue to rise.
