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  • Publication | 2026
Extreme heat and agriculture - FAO–WMO joint report
Global Food and Nutrition Security

This joint report by the FAO and the World Meteorological Organisation (WMO) provides an overview of the literature on extreme heat since the release of the Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC), focussing on the impacts on crops, livestock, fisheries and aquaculture, forestry, and agricultural workers. 

Extreme heat has emerged as one of the most serious and acute hazards facing agriculture around the globe, threatening food security and the livelihoods of billions. Extreme heat is a powerful risk multiplier with direct and indirect impacts across all the above mentioned agricultural subsectors. It amplifies existing hazards such as drought, heightens the risk of wildfires, and creates complex compound impacts that endanger not only production but also the health of agricultural workers, who are on the frontlines of the growing threat. 

Most major crops species exhibit negative yield responses at temperatures exceeding 30 °C, while most livestock species show negative responses above 25 °C. 

The analysis of scientific evidence and case studies presented in this report confirms that heat is already driving significant productivity losses: 

Observed impacts of extreme heat:

  • A meta-analysis estimates average global impacts on annual crop yields per 1 °C of warming as -7.5 % (±5.3) for maize, -1.2 % (±5.2) for rice, -6.8 % (±5.9) for soybean and -6.0 % (±3.3) for wheat 

  • The overall loss in total factor productivity in agriculture due to heat stress since 1961 is estimated at 21%, equivalent to the elimination of seven years of global productivity gains 

  • Yield losses and the global reduction in total agricultural factor productivity due to heat have led to an estimated 88 million more hectares being brought into production between 1992–2020 than would have otherwise been expected. This generated 21.8 billion tonnes of additional GHG emission (CO2 equivalent) equivalent to 18.9 % of the total land-use emissions for the countries involved 

  • Livestock: a study examining 56 million monthly milking from 2012 to 2016 found a loss of 1% in average annual milk yields due to heat stress; losses in qualitative characteristics (protein and fat content) having greater financial impacts for farmers than quantity. A study in Israel, involving 320 million daily milk records spanning a 12-year period, found that average daily milk yields were 0.5 % lower for each hour dairy cows were exposure to temperatures > 26 °C 

  • A study on mortality in dairy and beef cattle due to heat waves found that rates increased to 10 and 24% respectively. A study examining the death of 46 000 dairy cows during 8 major heatwaves over a six-year period found that dairy cows had a 20% higher chance of dying during a heatwave, and up to 30% in the summer before cattle had become acclimated to heat exposure.

Projected impacts of extreme heat:

  • From recent global studies, projected yield impacts resulting from 1 °C of warming estimate losses of 4-10 % for maize; 1.1-5.6% for rice; 2.9-5.4% for soy; and 3.8-10% for wheat 

  • Under high-emission scenarios, almost 50% of world’s cattle could be exposed to dangerous heat by 2100, with annual losses nearing USD 40 billion (in 2005 dollars) or 9.8% of current milk value, although under a low-emission scenario (SSP1-2.6), impacts from livestock exposure to extreme heat are reduced by nearly 66%. 

  • Recent studies indicates a potential loss of 400,000 lambs in Australia due to 1 °C of additional warming, the figure rising to 1.2 million lambs with 3 °C of warming, and a 5.6% decline of pig production in China, with hotter areas experiencing losses of 10% 

  • Fruit and nut trees and natural forests are also subject to production losses and the growing risk of more frequent and intense wildfires. Together, these losses create a dangerous feedback loop, where shortfalls in production can lead to agricultural expansion to compensate, increasing GHG emissions that fuel further climate change. 

Building resilience through adaptation to damaging changes that have already occurred and that are imminent is imperative. The need for adaptation action is particularly acute for the most vulnerable communities in the tropics and subtropics. Because extreme heat is predictable, strengthening climate services and early warning systems linked to anticipatory actions is a key opportunity. It is also clear that there are profound limits to what adaptation can achieve. With global mean temperatures on the cusp of exceeding the 1.5 °C warming limit outlined in the Paris Agreement, the urgency for adaptation and mitigation action only grows. The only durable solution to protect the future of global agrifood systems from the escalating threat of extreme heat lies in ambitious, multilateral climate change mitigation.