Extreme heat is pushing global food and farming systems to the brink, threatening the livelihoods of over a billion people as rising temperatures and more frequent heatwaves redefine how food is produced worldwide, a new UN report warns.
The joint report by the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO) finds that extreme heat is already causing half a trillion work hours to be lost each year, with impacts set to intensify as temperatures rise.
“Extreme heat is increasingly defining the conditions under which agrifood systems operate,” said WMO Secretary-General Celeste Saulo, warning that it acts “as a compounding risk factor that magnifies existing weaknesses across agricultural systems.”
The report highlights how heatwaves – prolonged periods of unusually high day and night temperatures – are affecting crops, livestock, fisheries and forests, while also putting agricultural workers at serious risk.
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A risk multiplier
Extreme heat is “a major risk multiplier,” said FAO Director-General Qu Dongyu, “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 already visible. For many major crops, yields begin to decline above 30°C (86°F), leading to weakened plant structures and reduced productivity. Livestock experience stress at even lower temperatures, particularly pigs and poultry, which cannot cool themselves efficiently, resulting in reduced growth, lower dairy yields and, in severe cases, organ failure.
In oceans, rising temperatures are lowering oxygen levels, putting fish under strain – with 91 per cent of the global ocean experiencing at least one marine heatwave in 2024. Forests are also affected, as extreme heat disrupts photosynthesis and increases the risk of wildfires.
Extreme heat also amplifies other climate risks. It can trigger droughts, worsen water scarcity, increase wildfire risks and accelerate the spread of pests and diseases – creating what the report describes as “compound effects” that ripple across entire ecosystems.
‘Severe impacts’ a reality
In some regions, these impacts are already severe.
A 2025 heat event in Kyrgyzstan, for example, saw temperatures rise around 10°C above normal, contributing to a 25 per cent decline in cereal harvests, while also triggering locust swarms and reducing irrigation capacity.
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Elsewhere, prolonged heat and drought conditions in Brazil in 2023 and 2024 cut soybean yields by as much as 20 per cent, while a major heatwave across North America in 2021 led to significant losses in fruit crops and a sharp spike in forest fires.
The human toll is equally stark. In parts of South Asia, sub-Saharan Africa and Latin America, the number of days too hot to work could rise to 250 per year – putting millions of agricultural workers at risk and undermining food production.
Call to action
To respond, the report calls for urgent adaptation measures, including heat-resilient crops, adjusted planting schedules and improved farm management practices.
Early warning systems and access to financial support – such as insurance and social protection – are also critical to help farmers cope with rising 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 UN agencies conclude.