As climate change accelerates global temperature rises and a new El Niño event approaches to strain underprepared food systems, international experts are sounding the alarm: extreme heat has already pushed global food production past critical thermal thresholds, and urgent action to build long-term heat readiness is required to avoid widespread shortages and harm.
Every component of the global food system – from staple grain crops to livestock to wild fisheries – has a specific thermal limit: a temperature point where heat stops being benign weather and becomes destructive. For most key agricultural species, this critical threshold arrives far earlier than public awareness suggests, with most growth and reproductive processes failing between 25°C and 35°C during sensitive growth stages such as flowering. Today, increasingly frequent heatwaves pushing temperatures into the mid-40s°C across the world’s major breadbasket regions have already pushed these systems past their safe limits. The consequences stretch across every link of the food supply chain: shrunken crop yields, weakened and dying livestock, stressed collapsing fisheries, elevated wildfire risk, and dangerous working conditions that threaten the farmworkers who form the foundation of global food production.
A joint report from the Food and Agriculture Organization (FAO) and the World Meteorological Organization (WMO), published April 22, quantifies the already tangible damage of rising heat to food systems. Documented extreme heat events have pushed beef cattle mortality as high as 24% in affected regions. Marine heatwaves have caused an estimated $6.6 billion in lost fisheries output. Projections show the situation will worsen as warming continues: for every 1°C of global temperature increase, average maize and wheat yields are expected to decline by 4 to 10%.
Adapting global food production to a hotter future requires sustained long-term investment in agricultural science, innovation, and infrastructure to match growing global food demand. This includes developing and deploying more heat-tolerant crop varieties and livestock breeds, updating conventional farming practices to account for rising temperatures, and making deliberate strategic choices about what crops and livestock can be sustainably raised in changing climates. But experts emphasize preparation cannot wait for mid-century or end-of-century targets – action is needed immediately to protect coming growing seasons.
With more intense heat forecast for the next several years and a new El Niño event on track to test systems that have not been updated to handle extreme heat, the top priority is shifting the global approach from reactive crisis response to proactive heat readiness. This transformation begins with accessible, actionable early warning systems and targeted practical interventions to help farmers protect their harvests, maintain stable supply chains, and safeguard their own health.
The United Nations’ Early Warnings for All initiative, coordinated by WMO with support from FAO and other partners, is built on the core idea that advance warning gives farmers time to protect their crops before heat causes irreversible loss. But early warnings only deliver value when they translate raw climate and weather data into specific, usable guidance for local producers, which requires robust observational infrastructure and localized modeling.
In Cambodia, the FAO-supported PEARL project, funded by the Green Climate Fund, has upgraded existing weather stations and installed new monitoring equipment to feed data to a mobile application that delivers crop-specific, region-tailored heat forecasts and guidance. When forecasts predict temperatures exceeding 38°C, the app sends targeted alerts recommending practical interventions: maintaining soil moisture through mulching, adding shade for sensitive vegetable crops, delaying rice sowing, and shifting irrigation to the cooler early morning and evening hours.
This guidance is part of a growing toolkit of low-cost, evidence-based interventions that cut producer losses before extreme heat escalates into a full-blown crisis. Other proven measures include shading crops with protective cloth or dual-purpose solar panels, expanding on-farm water storage capacity, installing low-cost cooling misters for livestock and high-value crops, and adjusting planting windows to avoid the hottest peak growth periods. For cattle, which generate excess metabolic heat during digestion, shifting feeding to cooler overnight hours reduces heat stress. Poultry, which lack the ability to sweat, require consistent shade to avoid mortality; in regions where extreme heat has become the new normal, many producers are shifting from heat-sensitive cattle to more tolerant goats and sheep as a viable adaptation.
Field trials in Pakistan demonstrate that these small adjustments deliver strong returns on investment. A FAO-GCF project tested a combined package of heat- and drought-tolerant cotton and wheat varieties paired with mulching and adjusted planting schedules over six growing seasons. The result: producers saw returns as high as $8 for every $1 invested in the adaptation package.
Extreme heat does not only damage food while it is still growing – it also accelerates post-harvest spoilage, turning crop stress into direct income loss for smallholders and reduced nutritional access for consumers. An estimated 526 million tonnes of global food production – roughly 12% of total annual output – is lost or wasted each year due to lack of adequate cold storage. In Jamaica, a GCF-funded, FAO-supported adaptation project has positioned cold chain infrastructure as a core climate adaptation measure, rolling out solar-powered cold storage units that let smallholders keep produce fresh and marketable during extreme heat events.
Even with cold chains and crop protection tools in place, the people who grow the world’s food remain at severe risk. Extreme heat is one of the deadliest workplace hazards for agricultural workers, causing acute dehydration, permanent kidney damage, chronic illness, and increased strain on already overburdened public health systems. More than one-third of the global workforce – around 1.2 billion people – face dangerous workplace heat exposure every year, and agriculture ranks among the hardest-hit economic sectors.
Proven basic protections for workers are already being implemented alongside crop guidance in Cambodia, where heat advisories also include recommendations for producers to shift heavy labor to cooler hours of the day and guarantee access to clean drinking water, shade, and regular rest breaks. The World Health Organization (WHO) and WMO are calling for this scaled-up integrated approach across all agricultural regions: adjusted work-rest schedules, guaranteed access to shade and safe water, training for workers and supervisors to recognize early signs of heat illness, and integration of climate forecasts into routine workplace heat risk management.
The tools and knowledge to prepare for increasing extreme heat already exist globally. The key gap holding back action is inadequate funding – far too little investment is allocated to agrifood system adaptation, and rural communities are often overlooked in climate planning that incorrectly frames extreme heat as primarily an urban problem. In 2023, just 4% of total global climate-related development finance went to agrifood system adaptation. Without a rapid increase in investment, early warnings will not reach the smallholder producers who need them most, agricultural extension services will remain underfunded, and basic protections for crops, livestock, and workers will remain out of reach for most vulnerable communities.
Experts emphasize that advance preparation is far more cost-effective than absorbing repeated annual losses from extreme heat events. Proactive planning stabilizes food production and consumer prices in the near term, while also creating space for the larger scientific and structural transformations that global agriculture will need to adapt to long-term warming.
This op-ed was contributed by Kaveh Zahedi, Assistant Director-General of the UN Food and Agriculture Organization and Director of FAO’s Office of Climate Change, Biodiversity and Environment, and Ko Barrett, Deputy Secretary-General of the World Meteorological Organization. “We don’t need a new playbook,” they write. “We need to use the one we already have. The FAO-WMO report lays out the risks of extreme heat. Now is the time to use that evidence to protect food systems and the people who sustain them.”