Extreme heat now poses one of the greatest threats to global food systems, according to a joint UN report from the FAO and WMO.
This blog post distills that assessment for researchers, policymakers, and practitioners.
It highlights who is affected, what the data show for crops and livestock, and what must change to build resilience.
The findings underscore how heat stress harms farmers’ ability to work, reduces yields, and disrupts marine life essential to fisheries and nutrition.
Escalating heat threatens livelihoods and food security
Across already hot regions—including much of India and South Asia, tropical Sub-Saharan Africa, and large parts of Central and South America—farmers could be unable to work safely for up to 250 days per year as temperatures rise.
Livestock begin to experience heat stress at about 25°C, with higher mortality, lower milk yields and quality, and, in pigs and chickens, digestive failure and organ stress as heat intensifies.
Most crops experience yield declines once temperatures exceed roughly 30°C, driven by weaker cell walls and toxin production.
In concrete terms, maize yields in some areas have fallen by around 10%, and wheat shows comparable declines.
Further losses are projected as temperatures surpass 1.5°C above preindustrial levels.
Ocean heatwaves lower dissolved oxygen and trigger mass die-offs of fish, intensifying food insecurity.
The report emphasizes that many heatwaves are predictable.
This underscores the need for better early warning systems to help farmers anticipate extremes and adapt in real time.
Impacts on people, crops and livestock
Farm labor safety, animal welfare, and crop health are central to the report’s warnings.
The convergence of heat stress, reduced yields, and degraded forage threatens livelihoods for more than a billion people who depend on farming and fisheries.
Livestock health and productivity decline as heat stress intensifies, while crops struggle with structural damage and toxin production.
This reduces both quality and quantity of harvests.
The cascading effects extend from rural households to urban food prices and national economies dependent on agriculture and export crops.
Adaptation as a necessity, and how warnings can help
The FAO-WMO analysis stresses that heatwaves are largely predictable and can be mitigated through proactive measures.
Warning systems that combine weather forecasts with mobile communications, extension services, and farmer-friendly advisories can empower producers to time irrigation, shading, rest periods, and harvest decisions.
Early warnings are not a substitute for adaptation.
They are a critical trigger for action that protects lives and livelihoods during extreme heat events.
Paths forward: policy responses and farming system reform
To build resilience, the report calls for robust adaptation, greater investment, and coordinated policy action.
Failure to adapt is likely to drive expansion of agricultural land into natural ecosystems and push higher emissions if the system remains locked into high-input, heat-vulnerable practices.
Stakeholder proposals for compensation, safety, and support
La Via Campesina’s Morgan Ody outlines concrete steps to shield workers and farms from heat impacts:
- Compensation and debt relief to ease the financial shock of climate-related losses.
- Public investment in adaptation—infrastructure, irrigation efficiency, and climate-resilient seeds and practices.
- Worker safety rules that limit exposure times during peak heat and ensure access to cooling, shade, and hydration.
- Enhanced shade, rest, and water provisions for field and boat workers to reduce heat-related risks.
Debate over farming models: diversity vs. monocultures
Critics argue that intensive, industrial monocultures and large-scale livestock systems magnify vulnerability to extreme heat and climate shocks.
They advocate a transition to diverse, nature-friendly farming that reintroduces trees, mixed crops, and integrated production systems.
Such systems can bolster resilience by spreading risk and enhancing soil health.
They also reduce dependency on external inputs.
Resilience is framed as a multi-layered effort—combining early warning, improved farming practices, and social protections for workers.
There is also a broader shift toward sustainable agricultural models that can thrive in a warming world.
Here is the source article for this story: World food systems ‘pushed to the brink’ by extreme heat, UN warns