The joint report from the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO) states that extreme heat already causes half a trillion working hours to be lost each year, with impacts expected to intensify as temperatures rise.
“Extreme heat increasingly defines the conditions under which agri-food systems operate,” said WMO Secretary-General Celeste Saulo, warning that it acts “as a compounding risk factor that magnifies existing vulnerabilities across agricultural systems.”
The report highlights how heat waves – long periods of unusually high day and night temperatures – affect crops, livestock, fisheries and forests, while putting agricultural workers at serious risk.
A risk multiplier
Extreme heat is “a major risk multiplier,” said FAO Director-General Qu Dongyu, “exerting increasing pressure on crops, livestock, fisheries and forests, and on the communities and economies that depend on them.”
Across farming systems, the effects 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, especially pigs and poultry, which cannot cool themselves effectively, resulting in reduced growth, lower milk yield and, in severe cases, organ failure.
In the oceans, rising temperatures lower oxygen levels, putting fish under stress – with 91 percent of global oceans experiencing at least one marine heat wave by 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, exacerbate water scarcity, increase the risk of wildfires 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 temperature increases around 10°C above normal, contributing to a 25 percent drop in the grain harvestwhile triggering swarms of locusts and reducing irrigation capacity.
Elsewhere, prolonged heat and drought conditions in Brazil in 2023 and 2024 reduced soybean yields by as much as 20 percent.while a major heat wave over North America in 2021 led to significant losses in fruit crops and a sharp increase in wildfires.
The human toll is just as tremendous. In parts of South Asia, sub-Saharan Africa and Latin America, the number of days too hot to work can increase to 250 per year – endangering millions of agricultural workers and undermining food production.
Extreme heat is reshaping agricultural conditions globally, threatening food security and rural livelihoods. (file image)
Call to action
To respond, the report calls for urgent adaptation measures, including heat-resistant 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 essential to help farmers cope with increasing risks.
“Protecting the future of agriculture and ensuring global food security requires not only building resilience on the farm, but also…a decisive transition away from a high-emissions future,” conclude the UN bodies.
