Paris (France) (AFP) – The increase in episodes of extreme heat is pushing agriculture “to the limit” around the world, and is already threatening the health and livelihoods of more than a billion people, the FAO and the World Meteorological Organization (WMO) warned on Wednesday.

Published on: 04/22/2026 - 10:57

The phenomenon, linked to global warming generated by human activities, already causes agriculture to lose 500 billion hours of work each year. Certain to intensify, it threatens global food security, underlines Wednesday the report “Extreme heat and agriculture”.

Extreme heat refers to temperatures that are “unusually hot” compared to normal, day and night. Their intensity promises to double if the world reaches +2°C of warming compared to the pre-industrial era (and to quadruple at +4°C), scientists warn.

Above all, they act in cascade, on humidity or solar radiation, generating torrential rains, "flash" droughts...

“It is to a certain extent THE trigger,” explains Kaveh Zahedi, director of the Climate Change Office at the FAO, to AFP.

"We saw it two years ago in Brazil: prolonged extreme heat, combined with drought, caused fires in the Amazon and the drying up of tributaries of the Amazon, with an immediate impact on the entire food system, including fishing and aquaculture; further south it generated abnormally intense rains. These are the kinds of convergences that we are just beginning to understand: it is not just extreme heat, but a multiplier of risks”.

Cases are piling up in the United States, Russia, China... and no sector is immune.

For livestock, when extreme heat does not cause digestive or cardiovascular failure, it reduces milk production and protein content.

Fish can experience heart failure in water where oxygen levels are reduced by high temperatures. However, in 2024, 91% of the ocean globally will have experienced at least one heat wave, half of which will be considered "strong", notes the report.

For most crops, yields begin to decline above 30°C - and earlier for potatoes or barley. Disappearance of pollinators, diseases or lack of food add to the risks, reinforced by the uniformity of varieties.

Indian rice, Bering crab

In Morocco, six years of drought crowned by two historic heat waves, in 2023 and 2024, reduced cereal yields by 40% and ruined olive and citrus harvests, recalls Mr. Zahedi.

This is also happening in the mountains, as in spring 2025, where temperatures of more than 30°C (10°C above normal) on the Kyrgyz Fergana range subjected fruits and cereals to thermal shock and an invasion of locusts. Bottom line: 25% fewer harvests.

Finally, at sea, in the eastern Bering Sea, a marine heatwave in 2018–2019 caused 90% of snow crabs to die, leading to the closure of one of the “most profitable” fisheries in the Arctic, the report notes.

Faced with this situation, "we see examples of innovative actions", underlines Mr. Zahedi, who mentions India where farmers are testing earlier varieties of rice.

A huge challenge in a country which derives 70% of its calories from it and where agriculture provides a living for millions of workers.

Heat peaks already affect more than a billion humans, primarily farmers and their families (health, productivity, etc.).

They also weaken food security that is already very uncertain (in 2024, 2.3 billion humans suffered from forms of food insecurity).

The report calls for adopting seeds and breeds adapted to new conditions. And to make warning systems available to farmers, as extreme heat is among the most predictable weather phenomena.

“We are seeing actions, but it is not enough,” insists the FAO official, emphasizing the “critical” importance of alert systems.

But without an “ambitious” reduction in greenhouse gases, “the severity of extreme heat will increasingly exceed the capacity to cope,” notes the report. “Building resilience is essential, but cannot replace determined climate action.”

© 2026 AFP

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