Extreme Heat and Agriculture: Global Risks to Crops, Livestock, Fisheries and Farm Workers

Extreme heat is rapidly changing the conditions under which the world produces food.

Its effects are no longer limited to visibly damaged crops or temporary reductions in farm productivity. Prolonged high temperatures can disrupt plant development, increase livestock stress, reduce oxygen in aquatic environments, intensify water scarcity and make outdoor agricultural work dangerous.

This means extreme heat must be understood not simply as a weather event, but as a global food-system risk.
 

Extreme heat affects agriculture by pushing crops, animals, aquatic species and agricultural workers beyond the temperatures at which they can function safely and productively.

It can reduce crop yields, lower livestock productivity, increase water demand, weaken disease resistance, affect fish survival and reduce the number of hours during which agricultural workers can operate safely.

The greatest risk emerges when heat combines with drought, water scarcity, humidity, wildfires, pests, diseases or weak agricultural infrastructure.
 

• Extreme heat affects every major component of agrifood systems.

• Crops can experience reduced pollination, impaired growth and lower yields.

• Livestock may eat less, produce less and face greater health and reproductive risks.

• Warmer aquatic environments can reduce dissolved oxygen and increase disease pressure.

• Farm workers face serious occupational-health and productivity risks.

• Early warnings, climate services, heat-resilient genetics and adapted management can reduce losses.

• Long-term resilience requires research, investment, insurance and coordinated public policy.

Agricultural production depends on biological processes that operate within particular temperature ranges.

When temperatures move beyond those ranges, plants and animals must use additional energy simply to survive. If the exposure continues, growth, reproduction, immunity and productivity begin to decline.

Extreme heat can also increase evaporation, intensify irrigation demand and accelerate moisture loss from soil. When heat occurs alongside drought or limited water availability, the damage becomes significantly more difficult to manage.

The result is a chain of connected risks affecting farms, food prices, rural employment, supply chains and national food security.
 

Crops are especially vulnerable during germination, flowering, pollination and grain or fruit development.

High temperatures can:

• Reduce photosynthesis
• Damage pollen and lower fertilization
• Shorten crop-growth periods
• Accelerate soil-moisture loss
• Increase plant respiration
• Reduce grain, fruit or vegetable quality
• Increase susceptibility to pests and diseases
• Cause premature crop maturity
• Reduce overall yield stability

The impact differs between crops, varieties, locations and stages of growth. A short heat event during a sensitive reproductive stage may cause greater damage than a longer event during a more tolerant stage.

This is why agricultural research must move beyond studying average seasonal temperatures. Researchers increasingly need to examine the timing, duration, night-time temperatures and interaction of heat with humidity, soil moisture and crop development.
 

Livestock generate body heat through metabolism, movement and digestion. Under normal conditions, animals release this heat into their environment.
During periods of high temperature and humidity, that process becomes less effective.

Heat-stressed animals may:

• Seek shade more frequently
• Increase water consumption
• Reduce feed intake
• Move less
• Produce less milk, meat or eggs
• Experience reduced fertility
• Become more vulnerable to disease
• Face organ stress under prolonged exposure

Poultry and pigs can be particularly vulnerable because their ability to regulate body temperature through sweating is limited.

The effects are not restricted to large commercial farms. Small livestock producers may face even greater risks when access to shade, ventilation, cooling systems, reliable water or veterinary services is limited.

Heat adaptation in livestock therefore requires a combination of housing design, water management, nutrition, genetics, health surveillance and early-warning information.

Aquatic systems are sometimes overlooked in discussions about agricultural heat stress.
However, warmer water contains less dissolved oxygen. Fish must then increase respiration while having less oxygen available to support it.

Extreme water temperatures can:

• Reduce feeding and growth
• Increase physiological stress
• Affect reproduction
• Raise the risk of disease outbreaks
• Increase mortality
• Alter the distribution of aquatic species
• Disrupt pond, lake, river and coastal ecosystems

Aquaculture producers may need real-time water-quality monitoring, aeration systems, adjusted feeding schedules, appropriate stocking densities and temperature-based early-warning services.

Climate-resilient aquaculture will increasingly depend on integrating environmental monitoring with fish-health management.

Agriculture remains heavily dependent on outdoor labour.
Farm workers, livestock handlers, fishers, forestry workers and food-chain labourers may be exposed to direct sunlight, humidity and physically demanding work for extended periods.

Heat exposure can cause:

• Dehydration
• Heat exhaustion
• Heatstroke
• Reduced concentration
• Lower physical capacity
• Greater risk of workplace accidents
• Lost working hours
• Long-term health consequences

Protecting agricultural workers requires access to drinking water, shaded rest areas, adapted work schedules, heat alerts, appropriate clothing and clear emergency procedures.

Worker protection should be treated as an essential part of climate-resilient agriculture rather than as a separate labour issue.

Extreme heat rarely acts alone.

It can combine with:

• Drought and water scarcity
• Wildfire risk
• Soil degradation
• Pest expansion
• Animal and plant diseases
• Power disruptions
• High irrigation demand
• Feed shortages
• Market instability
• Rural poverty

For example, a livestock producer may face high animal water demand at the same time that local water availability is declining. A crop farmer may experience heat-related yield losses while also paying more for irrigation and pest management.

These overlapping pressures can turn a climatic hazard into a financial and food-security crisis.

Extreme heat is a global challenge, but exposure and adaptive capacity are uneven.
South Asia faces major risks related to outdoor labour, densely populated farming regions and high night-time temperatures.

Parts of Africa face the combined pressure of rising temperatures, water scarcity, limited climate services and dependence on rain-fed agriculture.
The Middle East and North Africa must manage extreme heat alongside severe water constraints.

Europe is experiencing increasing risks to crops, livestock and rural landscapes during prolonged heatwaves.

Latin America and the Caribbean face changing heat, rainfall, wildfire and ecosystem conditions across highly diverse production systems.
Regional adaptation must therefore reflect local crops, livestock species, water systems, farm sizes and economic conditions. A single universal solution will not be sufficient.
 

1. Improve Early-Warning Systems
Farmers need forecasts that translate temperature data into practical agricultural decisions. Warnings should indicate when to irrigate, change feeding schedules, move livestock, activate cooling, adjust working hours or prepare aquaculture systems.

2. Develop Heat-Resilient Crops and Animals
Selective breeding, genomic research and biotechnology can support varieties and breeds that maintain productivity under higher temperatures.Resilience should be evaluated across real farming environments rather than only under controlled conditions.

3. Adjust Agricultural Calendars
Changing planting dates, harvesting periods and livestock-management schedules can reduce exposure during the most dangerous temperature periods.

4. Improve Water and Soil Management
Efficient irrigation, mulching, soil organic matter, rainwater storage and moisture conservation can help protect crops and reduce heat-related water stress.

5. Redesign Livestock Housing
Shade, ventilation, cooling, reflective roofing and reliable access to water can lower animal exposure.

6. Strengthen Aquaculture Monitoring
Temperature, dissolved oxygen, pH and other water-quality parameters should be monitored together. Alerts must be connected to clear action protocols.

7. Protect Agricultural Workers
Heat-safety standards should include rest breaks, hydration, shaded areas, flexible working hours and emergency-response training.

8. Expand Financial Protection
Insurance, emergency finance, social protection and risk-sharing mechanisms can help producers recover without abandoning productive assets.

The next generation of extreme-heat research should focus on:

• Crop and livestock thresholds under local conditions

• Combined heat and humidity effects

• Night-time heat exposure

• Heat interactions with pests and disease

• Water and energy demand during heat events

• Low-cost cooling for small farms

• Climate-resilient aquaculture

• Occupational heat protection

• Economic losses across agricultural value chains

• Adaptation solutions suitable for smallholders

Researchers must also communicate results in formats that farmers, extension officers and policymakers can use quickly.
 

Extreme heat is becoming one of the defining agricultural risks of the present decade.

Its effects extend from crop fields and livestock farms to ponds, fisheries, forests, labour systems and food markets.

Agricultural resilience will depend on how successfully climate science, biological research, farm management, early-warning systems, worker protection and public policy are connected.

The question is no longer whether agriculture will need to adapt to extreme heat.
The question is whether research, institutions and investment can move quickly enough to protect the people and biological systems responsible for feeding the world.