Extreme heat is already undermining global food production and labor capacity, emerging as a systemic “risk multiplier” that is pushing agrifood systems toward crisis, a new United Nations report warned.
The report, released by the UN Food and Agriculture Organization and the World Meteorological Organization, says rising temperatures and more frequent heatwaves are reshaping how food is produced worldwide and placing crops, livestock, and food-dependent communities under growing strain.
“Extreme heat is increasingly defining the conditions under which agrifood systems operate,” WMO Secretary-General Celeste Saulo said, warning that it acts “as a compounding risk factor that magnifies existing weaknesses across agricultural systems.”
The report found that extreme heat is already causing half a trillion work hours to be lost each year, as rising temperatures reduce the number of safe working hours for agricultural laborers. The losses are expected to increase as global temperatures continue to rise.
FAO Director-General Qu Dongyu described the trend as systemic, calling extreme heat “a major risk multiplier” that is “exerting mounting pressure on crops, livestock, fisheries and forests, and on the communities and economies that depend upon them.”
Across farming systems, the impacts are becoming more pronounced. Many major crops begin to lose productivity when temperatures exceed 30°C, leading to weakened plant structures and reduced yields. Livestock, particularly pigs and poultry, experience stress at even lower temperatures, resulting in reduced growth, lower dairy yields, and, in severe cases, organ failure.
Marine and forest ecosystems are also under strain. Warmer ocean temperatures are reducing oxygen levels and stressing fish populations, with 91 percent of the global ocean experiencing at least one marine heatwave in 2024. On land, extreme heat disrupts photosynthesis and increases the risk of wildfires.
The report warned that extreme heat amplifies other climate risks, triggering droughts, worsening water scarcity, increasing wildfire risks, and accelerating the spread of pests and diseases. These “compound effects” are rippling across ecosystems and food systems, deepening vulnerabilities in already fragile regions.
In some regions, the impacts are already severe. A 2025 heat event in Kyrgyzstan saw temperatures rise about 10°C above normal, contributing to a 25 percent decline in cereal harvests while triggering locust swarms and reducing irrigation capacity. In Brazil, prolonged heat and drought in 2023 and 2024 cut soybean yields by up to 20 percent, while a 2021 heatwave in North America led to significant losses in fruit crops and a sharp increase in forest fires.
The human toll is also rising. In parts of South Asia, sub-Saharan Africa and Latin America, the number of days considered too hot to work could reach up to 250 per year, placing millions of agricultural workers at risk and undermining food production.
The UN agencies called for urgent adaptation measures, including heat-resilient crops, adjusted planting schedules, and improved farm management practices. They also underscored the need for early warning systems and expanded access to financial support, such as insurance and social protection, to help farmers cope with growing climate risks.
“Protecting the future of agriculture and ensuring global food security will require not only building on-farm resilience but also…a decisive transition away from a high-emissions future,” the agencies said.
