How Biofouling Increases CO₂ Emissions in Global Shipping

BARNAGARD
15 hours ago
3 min read

Global shipping moves around 90% of the world’s trade, transporting everything from food and raw materials to electronics and vehicles. While ships are already a relatively efficient way to move goods, a hidden issue beneath the waterline can dramatically reduce their efficiency: biofouling.

Biofouling occurs when marine organisms such as barnacles, algae, mussels, and slime accumulate on submerged surfaces. For ships, this buildup happens primarily on the hull and underwater equipment. While it may seem like a small issue, biofouling has a significant impact on fuel consumption and global carbon emissions.

What Is Biofouling?

Biofouling is the process by which marine organisms attach and grow on surfaces in the water.

This growth typically develops in stages:

Slime layers of bacteria and microorganisms
Algae and soft growth
Hard fouling organisms like barnacles and mussels

Over time, these layers create a rough surface that disrupts smooth water flow along a ship’s hull.

Why Hull Smoothness Matters

Ships are designed with smooth hulls to reduce friction as they move through the water. Even small changes to the hull surface can dramatically affect how efficiently a vessel travels.

When biofouling develops, it increases hydrodynamic drag - the resistance created as the ship moves through the water.

More drag means the ship must use more engine power and more fuel to maintain the same speed.

The Fuel Penalty of Marine Growth

Studies in the shipping industry have shown that even minor fouling can reduce efficiency.

Typical impacts include:

Light slime: 5–10% increase in fuel consumption
Moderate fouling: 15–25% increase in fuel consumption
Heavy barnacle growth: up to 40% more fuel required in extreme cases

For large cargo vessels that burn massive amounts of fuel daily, even a small percentage increase can translate into millions of dollars in additional fuel costs each year.

The Carbon Emissions Impact

When ships burn more fuel, they also produce more greenhouse gases. Shipping currently contributes roughly 3% of global CO₂ emissions, according to international maritime studies. Biofouling increases this number by forcing vessels to burn additional fuel simply to overcome drag.

Across the global fleet, poorly maintained hulls can add millions of tons of unnecessary carbon emissions each year.

Reducing hull fouling is therefore one of the simplest ways to improve shipping efficiency and reduce environmental impact.

Maintenance and Cleaning Challenges

To combat biofouling, ships are periodically cleaned or repainted with anti-fouling coatings.

However, these solutions often require:

Dry-docking the vessel
Specialized underwater cleaning services
Reapplication of coatings every few years

Because global shipping fleets operate continuously across oceans, keeping hulls completely free of fouling can be difficult.

Prevention as a Sustainability Strategy

Many shipping companies are now focusing on preventing biofouling rather than constantly removing it.

Preventative technologies can help maintain smoother hull surfaces for longer periods, improving efficiency and reducing the fuel required for transportation.

Solutions from Barnagard are designed to help reduce marine organism attachment on submerged surfaces. By limiting the ability of barnacles and other organisms to attach, preventative approaches can help keep underwater surfaces cleaner and more efficient over time.

For shipping operators, this can contribute to:

Lower fuel consumption
Reduced maintenance downtime
Improved vessel performance
Lower overall emissions

The Bigger Picture

As the global shipping industry works toward sustainability goals and emissions reductions, improving vessel efficiency is a critical step.

Biofouling may occur beneath the waterline and out of sight, but its effects are felt across the entire shipping ecosystem, from fuel costs to environmental impact.

By addressing marine growth early and maintaining cleaner hull surfaces, shipping companies can reduce unnecessary fuel use and help move global trade more efficiently and sustainably.

Contact support@barnagard.com today to inquire about our premium, eco-friendly coatings.