The garbage men of the sea

Have you ever wondered how you, as a seafarer, can help rid the world's oceans of plastic pollution? Helen Kelly spoke with Laurent Lebreton of The Ocean Cleanup to find the answers

When you picture the Great Pacific Garbage Patch, you might imagine a vast floating island of rubbish. The reality is far more insidious. Dispersed across 1.6 million square kilometres – an area larger than most countries – approximately 100,000 tonnes of plastic debris drifts in a 'plastic soup' halfway between Hawaii and California. And it's growing.

The Ocean Cleanup, a Netherlands-based nonprofit, is pioneering revolutionary technology to tackle this environmental crisis, and seafarers are playing a crucial role in their mission.

Understanding the scale of the problem

The Ocean Cleanup's head of research Laurent Lebreton has spent 15 years studying how plastic moves through our oceans. His work combines physical oceanography with cutting-edge modelling to map plastic pollution and design solutions.

'The Great Pacific Garbage Patch is not a floating island,’ Mr Lebreton explains. 'If it was, it would be much easier. We could go there with a boat and a crane and just pick up everything. But it is dispersed over a very, very wide surface area.'

The patch is one of five subtropical gyres worldwide where ocean currents converge, causing floating matter to accumulate. Fly over it, and you’ll see blue ocean. Sail through it, and the disturbing truth becomes apparent:countless fragments of plastic contaminate the water.

There are two metrics used to measure the plastics in the ocean: the number of pieces of plastic and the total mass. 'If you look at the number of pieces of plastic, the majority of these are microplastics – over 90% are tiny fragments. But if you look at the mass, essentially the total mass is carried by larger objects. So about three quarters of the mass in the Great Pacific Garbage Patch is objects several centimetres or even several metres in size,' Mr Lebreton explains.

Much of the larger objects come from the maritimeindustry: fishing nets, ropes,buoys, crates, and other debris.

The technology behind the cleanup

The Ocean Cleanup's solution is a 2.5km-wide barrier towed by two vessels at just 1.5 knots – half of walking speed. The C-shaped barrier concentrates plastic at its centre into a retention zone, which fills over two to three days before being hauled aboard for processing.

Environmental protection is built into the design. Observers monitor for marine mammals, whilst cameras inside the retention zone detect any trapped animals.
Sea turtles, which occasionally wander into the system, can escape through a safety hatch. Marine mammals, LeBreton notes, are 'smart enough to get away.'
Each extraction removes 8-12 tonnes of plastic, though the team knows they can do better. They’ve paused ocean operations to focus on detecting 'hotspots' – concentrated areas of plastic that could halve cleanup costs and time if targeted effectively.

The $7.5 billion question

The Ocean Cleanup estimates that removing the Great Pacific Garbage Patch entirely would cost approximately $7.5 billion (£5.9 billion) over 10 years – a figure that may sound astronomical until you consider what we spend on waste management on land, says Mr Lebreton. By improving hotspot detection, he believes they can cut that figure in half.

Until recently, the organisation partnered with Maersk for vessel access. Funding has come primarily from philanthropy, though Mr Lebreton is hopeful that international agreements on plastic pollution could unlock institutional government funding.

'The Great Pacific Garbage Patch is in international waters, so it's in no one's jurisdiction at the moment,' he explains. 'It's everyone's problem, but no one's problem.'

Yet when the team recover plastic, they can trace brands and markings back to source countries, creating accountability.

Intercepting plastic at source

The Ocean Cleanup operates approximately 20 river interception systems across nine countries, preventing plastic from ever reaching the ocean. Over 90% of plastic from rivers ends up on coastlines.

These river systems serve a dual purpose: removing plastic and gathering intelligence. By analysing what they collect – polymer types, uses, sources – the team provide data that can inform upstream policies and mitigation strategies.

'We take that pollution level and bring visibility to it, and then also report on the type of pollution,' Mr Lebreton says. 'Then upstream mitigation measures can be implemented and eventually we don't need to do our work.

'We always say we want to run out of business. We don't want to be garbage men of the ocean forever'.

The maritime industry's essential role

For Laurent Lebreton, who has spent considerable time at sea on research vessels collecting data, the maritime community's involvement is vital to success. The organisation has developed the Automated Debris Imaging System (ADIS) – a small, smart camera using artificial intelligence to automatically detect plastic debris.

These cameras, currently deployed onvessels operated by partners like Hyundai Glovis, continuously collect data as ships traverse the globe. The information helps calibrate numerical models and identify those crucial hotspots.

But there's a challenge: whilst cleanup operations remove plastic, they also generate CO2 emissions. The Ocean Cleanup is watching the maritime industry's decarbonisation efforts closely.

'If we could get decarbonised operations, that would be just ideal,' Mr Lebreton says.

Operating at just 1.5 knots presents unique opportunities for alternative fuels or propulsion systems. 'We don't have the capacity to develop those kinds of things. That's where I'm hoping we can get the industry to come up with solutions and offer us the opportunity to have a carbon neutral cleanup of the ocean.'