The Pandora’s Box of Heatwaves and the Shipping Market

New York bulker owner Genco Shipping & Trading this week after the company presented a slide on the potential impact of an El Nino weather pattern on water levels.

The presentation noted expert forecasts of an 81% chance of a strong El Nino event from October to December, and a 97% chance that it persists through early spring.

The El Nino pattern would make some regions wetter and others drier. It notably reduced water levels in the canal in 2023, causing a major reduction in transits and boosting hire rates for some operating sectors.

Rivers Become Less Navigable

For inland waterways such as the Rhine River in Europe, Mississippi River in the United States, Yangtze River in China and parts of South America, lower water levels mean vessels cannot safely sail fully loaded.

The consequences include:

• Reduced cargo per voyage
• More voyages required to transport the same cargo volume
• Higher inland transportation costs
• Delays in cargo reaching export terminals

When inland logistics slow, seaborne shipping schedules may also be affected.

Energy Demand Surges

During severe heatwaves, electricity consumption often rises sharply as households and industries increase air-conditioning usage.

Power utilities respond by increasing fuel consumption, including:

• LNG
• Fuel oil
• Coal
• Diesel
• Natural gas

For tanker and gas shipping markets, this may generate additional cargo movements, particularly where countries rely on imported energy.

Refineries Face Operational Stress

Extreme temperatures may reduce refinery efficiency.

High ambient temperatures can:

• Lower cooling efficiency
• Increase maintenance requirements
• Reduce operational flexibility

Unexpected refinery outages may alter regional product balances, leading to:

• Increased imports
• Emergency cargoes
• Longer trading routes

These changes may create additional opportunities for clean petroleum product tankers.

Agricultural Trade Patterns Shift

Heatwaves can reduce crop yields through drought and water shortages.

When domestic agricultural production falls, countries may increase imports of:

• Vegetable oils
• Grains
• Feedstocks
• Biofuel feedstocks

Conversely, exporting nations suffering poor harvests may reduce exports altogether.

These shifts affect demand for both tanker and dry bulk segments, particularly where edible oils and biofuel feedstocks such as palm oil, PFAD and used cooking oil are involved.

Higher Vessel Operating Costs

Heat also affects vessels directly.

Higher temperatures may result in:

• Greater air-conditioning load onboard
• Increased auxiliary engine usage
• Higher fuel consumption
• Faster deterioration of equipment exposed to extreme temperatures

Although these cost increases are relatively modest per voyage, they become meaningful over large fleets operating continuously.

Port Productivity Can Decline

Many ports around the world increasingly implement worker safety measures during extreme heat.

This may include:

• Reduced outdoor working hours
• Additional rest periods
• Temporary work stoppages

Cargo operations may therefore proceed more slowly, particularly where manual labour remains significant.

Longer port stays effectively reduce available vessel supply, which can contribute to firmer freight markets if delays become widespread.

Crew Welfare Becomes Increasingly Important

Perhaps the least discussed consequence is human performance.

Crew members working on deck under temperatures exceeding 40°C face:

• Heat exhaustion
• Fatigue
• Reduced concentration
• Increased accident risk

Protecting seafarer welfare is not merely a humanitarian responsibility—it also contributes directly to operational reliability and safety.

Cargo Deterioration During Voyage due to Heat

Possible consequences include:

• Changes in cargo viscosity or physical characteristics
• Accelerated oxidation or chemical degradation
• Increased vapour generation and pressure management requirements
• Greater risk of off-specification cargo upon arrival
• Additional cooling, ventilation or temperature-monitoring requirements
• Increased potential for quality disputes and cargo claims

Looking Ahead

Heatwaves should therefore be viewed not simply as weather events, but as another strategic market indicator.El Niño and La Niña can amplify or redistribute drought, rainfall, heat and storm risks, with consequences for waterways, ports, cargo flows, energy demand and vessel availability. A drought at a strategic canal, flooding at an export hub or a weather-driven change in commodity production can alter voyage distances, effective tonnage supply and freight rates well before the impact is visible in headline trade data.