Extreme Heat Threatens Global Food Systems: UN

Crops and livestock are under growing strain as heatwaves intensify across key agricultural regions. (file photo)

Extreme heat is pushing global food and farming systems to the brink, threatening the livelihoods of more than a billion people as rising temperatures and frequent heatwaves reshape how food is produced worldwide, a new UN report warns.

The joint report by the Food and Agriculture Organization and the World Meteorological Organization finds that extreme heat is already causing around half a trillion working hours to be lost each year, with impacts expected to intensify as temperatures continue to rise.

“Extreme heat is increasingly defining the conditions under which agrifood systems operate,” said 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 placing agricultural workers at serious risk.

A growing risk multiplier

Extreme heat is a “major risk multiplier,” said Qu Dongyu, adding that it is exerting increasing pressure on food systems and the communities that depend on them.

Across agriculture, the effects are already evident. Crop yields often begin to decline above 30°C, weakening plant structures and reducing productivity. Livestock are vulnerable at even lower temperatures, especially pigs and poultry, which struggle to regulate body heat, leading to reduced growth, lower milk production and, in extreme cases, death.

In oceans, rising temperatures are lowering oxygen levels, placing marine life under stress. In 2024, 91 per cent of the global ocean experienced at least one marine heatwave. Forest ecosystems are also at risk, as extreme heat disrupts photosynthesis and increases the likelihood of wildfires.

The report notes that heat amplifies other climate risks, including drought, water scarcity, pest outbreaks and disease spread, creating “compound effects” across ecosystems.

Severe impacts already visible

In some regions, the impacts are already severe. A 2025 heatwave in Kyrgyzstan saw temperatures rise about 10°C above normal, contributing to a 25 per cent drop in cereal production, alongside locust infestations and reduced irrigation capacity.

Similarly, prolonged heat and drought in Brazil during 2023 and 2024 reduced soybean yields by up to 20 per cent. In North America, a major heatwave in 2021 caused significant crop losses and increased forest fires.

The human cost is also rising. In parts of South Asia, sub-Saharan Africa and Latin America, the number of days too hot to work could reach up to 250 per year, putting millions of agricultural workers at risk and disrupting food production.

Urgent need for action

The report calls for immediate adaptation measures, including the development of heat-resistant crops, revised planting schedules and improved farm management practices.

It also stresses the importance of early warning systems and financial support mechanisms, such as insurance and social protection, to help farmers cope with growing risks.

The UN agencies emphasise that safeguarding global food security will require both strengthening resilience at the farm level and accelerating efforts to reduce greenhouse gas emissions.