The resurgence of episodes of extreme heat is pushing agriculture to the limit worldwide, threatening the health and livelihoods of over a billion people, warned the FAO and the World Meteorological Organization (WMO) on Wednesday.
The phenomenon, linked to climate change fueled by human activities, is already causing the agriculture sector to lose 500 billion working hours each year. Intensifying, 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 will double if the world reaches +2°C of warming compared to the pre-industrial era (and quadruple at +4°C).
Moreover, these extreme temperatures trigger cascading effects, impacting humidity or solar radiation, leading to heavy rains, “flash” droughts, among other consequences.
“As we witnessed two years ago in Brazil: prolonged extreme heat, combined with drought, triggered fires in the Amazon and the drying up of Amazon tributaries, with an immediate impact on the entire food system, including fishing and aquaculture; further south, it led to abnormally intense rains. This is the kind of convergences that we are just starting to understand: it’s not just extreme heat, but a multiplier of risks,” explained Kaveh Zahedi, director of the FAO’s Climate Change Office.
Cases of extreme heat are accumulating in the United States, Russia, China, and affecting every sector.
For livestock, extreme heat can lead to digestive or cardiovascular failures, reduce milk production, and protein content.
Fish can experience heart failure in waters with reduced oxygen levels due to high temperatures. The report notes that in 2024, 91% of the ocean globally experienced at least one heatwave, with half classified as “strong”.
For most crops, yields start declining below 30°C – and even earlier for crops like potatoes or barley. The disappearance of pollinators, diseases, or food shortages add to the risks, amplified by the uniformity of varieties.
Amid this situation, innovative actions are being seen, like in India where farmers are testing early-maturing rice varieties, a significant step in a country where 70% of calories come from rice and agriculture supports millions of workers.
Peak heat affects over a billion humans, primarily farmers and their families, impacting health, productivity, and exacerbating already uncertain food security (in 2024, 2.3 billion people suffered from various forms of food insecurity).
The report calls for the adoption of seeds and breeds suited to new conditions, the establishment of alert systems for farmers, as extreme heat events rank among the most predictable phenomena.
“We see actions, but they are not enough,” emphasized the FAO official, stressing the “critical” importance of alert systems.
However, without an “ambitious” reduction in greenhouse gas emissions, “the severity of extreme heat will increasingly exceed our ability to cope,” notes the report. “Building resilience is essential, but it cannot replace determined climate action.”
