The resurgence of extreme heat pushes global agriculture to its limits

The resurgence of extreme heat episodes is pushing agriculture “to the brink” around the world, threatening the health and livelihoods of over one billion people, warned the FAO and the World Meteorological Organization (WMO) on Wednesday.

The phenomenon, linked to climate change driven by human activities, is already causing the agriculture sector to lose 500 billion working hours each year. Expected to intensify, it poses a threat to global food security, as highlighted in the report “Extreme Heat and Agriculture.”

Extreme heat refers to temperatures that are “exceptionally hot” compared to normal, both during the day and at night. Scientists warn that their intensity is set to double if the world reaches a +2°C warming compared to pre-industrial levels (and quadruple at +4°C).

These extreme heat waves have cascading impacts on humidity, solar radiation, leading to heavy rainfall, “flash” droughts…

“It is to some extent the trigger,” explained Kaveh Zahedi, Director of the FAO Climate Change Office, to AFP. He cited the example from two years ago in Brazil where prolonged extreme heat combined with drought led to fires in the Amazon and the drying up of tributaries of the Amazon, affecting the entire food system, including fishing and aquaculture; further south, it caused abnormally intense rains. These are the kinds of convergences that we are just beginning to understand: it’s not just extreme heat, but a multiplier of risks.

Cases of extreme heat are accumulating in the United States, Russia, China, affecting every sector.

For livestock, extreme heat can lead to digestive or cardiovascular failures, reduce milk production, and protein content.

Fish can face heart failure in waters with reduced oxygen levels due to high temperatures. In 2024, 91% of the ocean globally experienced at least one heatwave, with half being classified as “strong,” according to the report.

For most crops, yields start to decline below 30°C – even earlier for potatoes or barley. The disappearance of pollinators, diseases, or lack of food add to the risks, amplified by the uniformity of varieties.

In Morocco, six years of drought followed by two historic heatwaves in 2023 and 2024 reduced cereal yields by 40% and destroyed olive and citrus crops. In the spring of 2025, temperatures exceeding 30°C (10°C above normal) in the Kyrgyz Fergana chain subjected fruits and cereals to thermal shock and a locust invasion, resulting in a 25% reduction in crops.

In the Bering Sea, a marine heatwave in 2018-2019 led to the death of 90% of snow crabs, prompting the closure of one of the “most profitable” fisheries in the Arctic.

To address this situation, there have been innovative actions, such as in India where farmers are testing early-maturing rice varieties. This is crucial in a country where 70% of calories are derived from rice and agriculture supports millions of workers.

Heatwaves affect over one billion people, primarily farmers and their families (health, productivity…), and also undermine an already uncertain food security (in 2024, 2.3 billion individuals were experiencing some form of food insecurity).

The report calls for the adoption of seeds and breeds suited to new conditions and the provision of alert systems for farmers, as extreme heat represents one of the most discernible phenomena.

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

However, 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 it cannot replace determined climate action.”

————————————————————————– Context: The FAO and the World Meteorological Organization raised alarm about the increasing impact of extreme heat episodes on agriculture worldwide. Fact Check: Extreme heat events, exacerbated by climate change, are threatening global food security and the livelihoods of over one billion people, according to a joint report by the FAO and the WMO.