Extreme heat threatens global food systems, UN agencies warn
FAO and WMO say intensifying heatwaves are threatening crops, livestock, fisheries, and the livelihoods of more than one billion people tied to agrifood systems.
Global food systems are entering a period of higher climate risk as extreme heat becomes more destructive and more frequent. That is the message from a new warning by the Food and Agriculture Organization of the United Nations and the World Meteorological Organization, reported by Reuters on April 22, 2026. The agencies said intensifying heat is threatening the livelihoods and health of more than one billion people connected to agrifood systems.
The warning stresses that heatwaves are becoming more frequent, more intense, and more prolonged. The impact goes beyond field crops to livestock, fisheries, and forests. Extreme heat acts as a risk multiplier by worsening drought, wildfire, and pest outbreaks, while sharply reducing yields once critical temperature thresholds are crossed. The report says most major crops begin to see meaningful yield losses once temperatures rise above about 30 degrees Celsius.
The backdrop is worsening because overall warming is accelerating. According to the report, 2025 ranked among the three hottest years on record. If global average temperatures continue to rise, the intensity of extreme heat events is expected to increase nonlinearly: roughly doubling at 2 degrees Celsius of warming and quadrupling at 3 degrees compared with a 1.5 degree pathway. Marine heat is also adding pressure. In 2024, 91 percent of the world’s oceans experienced at least one marine heatwave, threatening oxygen levels in water and putting additional stress on fish stocks.
FAO climate office head Kaveh Zahedi cited Morocco as a clear example of what compound heat stress can do. After six years of drought, the country was hit by record heatwaves, and cereal yields fell by more than 40 percent while olive and citrus harvests failed. Zahedi also said each one-degree rise in average global temperatures cuts yields of the world’s four major crops, maize, rice, soy, and wheat, by about 6 percent. That turns heat risk into a direct farm-economy and food-security issue rather than an abstract environmental concern.
FAO and WMO argue that piecemeal responses are no longer enough. They call for stronger climate-risk governance and broader early-warning systems so farmers and fishers can adjust planting dates, harvesting plans, and production choices before damage escalates. At the same time, the report says adaptation on its own will not solve the problem. The only durable way to reduce the threat of extreme heat is coordinated action to curb climate change. For agriculture, that means weather services, technology choices, insurance, and long-term climate policy are becoming increasingly interdependent.