Image credit: ©FAO/Bayan Ksiebi
Extreme heat is one of the most urgent and least understood hazards facing global agriculture, threatening food security and the livelihoods of billions. That’s according to a joint report by the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO), which examines how rising temperatures and more frequent heatwaves are impacting agrifood systems around the world.
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.”
These impacts are already visible. For many major crops, yields begin to decline above 30°C (86°F). Livestock, especially pigs and poultry, experience stress at even lower temperatures, which can lead to organ failure in severe cases.
In oceans, rising temperatures are reducing oxygen levels, putting fish under strain. Forests are also affected, as extreme heat disrupts photosynthesis and increases the risk of wildfires.
Extreme heat amplifies other climate risks – triggering drought, worsening water scarcity, heightening wildfire risk and accelerating the spread of pests and diseases. These so-called “compound effects” spread across entire ecosystems, the report says.
Severe Impacts
In some regions, the impacts of extreme heat are already severe. In Brazil, prolonged heat and drought in 2023 and 2024 reduced yields of soy and first season maize. The impact was particularly acute at a subnational level, with soy yields estimated to have decreased by more than 20% in São Paulo. First season maize crops were similarly affected.
Meanwhile, a major heatwave across North America in 2021 increased forest fires by 21-24% and caused substantial losses in fruit crops. Raspberry and blackberry yield losses ranged from 60–100% across locations, while blueberry losses ranged from none to nearly 100%.
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.
Recommended Actions
The report calls for a transformative approach to extreme heat, “grounded in proactive adaptation, integrated governance and ambitious climate change mitigation.” Climate-resilient practices, improved water and land management, heat-tolerant crops and breeds and strengthened risk governance are just some of the recommendations.
Early warning systems and access to financial support, such as insurance and social protection, are also seen as critical to helping 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.