Extreme heat pushes global food systems to brink, UN warns

Global food systems are under growing strain from extreme heat, which threatens agricultural production and the livelihoods of more than 1 billion people, according to a report released Wednesday by the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO). The report found that extreme heat currently causes approximately half a trillion work hours to be lost each year, and warned that damage to crops, livestock, and fisheries will likely worsen as temperatures continue to rise. The frequency, intensity, and duration of extreme heat events have increased sharply over the past five decades, creating escalating risks for rural communities and the economies that depend on them.

Impact on crops, livestock, and workers

FAO Director-General Qu Dongyu noted that extreme heat acts as a “major risk multiplier,” exerting mounting pressure on agricultural systems. Most livestock species begin suffering heat stress above 25°C (77°F), with chickens and pigs especially vulnerable as they cannot cool themselves through sweating. For major crops including wheat, potatoes, and barley, yields begin to decline above 30°C (86°F). Fisheries are also at risk: warmer waters reduce oxygen levels and increase cardiac failure in fish. In 2024, 91% of the global ocean experienced at least one marine heatwave. Agricultural workers face serious dangers as well, with parts of South Asia, Sub-Saharan Africa, and Central and South America facing up to 250 days per year too hot for safe labor.

Heat as risk multiplier

WMO Secretary-General Celeste Saulo said extreme heat is “increasingly defining the conditions under which agrifood systems operate.” The report warned that extreme heat amplifies droughts, wildfires, pests, and diseases, citing cases in the US, Russia, Brazil, China, and Australia where heatwaves triggered flash droughts and major crop losses. The agencies called for stronger early warning systems, climate-adapted farming practices, financial support, and international cooperation. “Protecting the future of agriculture and ensuring global food security will require not only building on-farm resilience but also exercising international solidarity and collective political will for risk sharing, and a decisive transition away from a high-emissions future,” the report concluded.