Plastic concerns all of us. Here is an article, translated from German, about a positive approach towards cleaning up the oceans and rivers.
Christof Gertsch, and Sebastian Broschinski (Das Magazin)
Published: 28.03.2025, 16:00
Plastic threatens the oceans The great clean-up of the world’s oceans
A young Dutchman is pursuing a bold mission: to rid the oceans of plastic waste. Whether he will be successful also depends on an Appenzell scientist.
No one feels responsible because the catastrophe is taking place in a space that belongs to no one: the vast sea.
The Pacific garbage patch
On an area three times the size of France, 1.8 trillion pieces of plastic float in the Pacific.
On September 8, 2018, a ship belonging to the Maersk shipping company left San Francisco Bay with an unusual mission: to clean up the sea. The destination was a pile of garbage in the Pacific halfway between California and Hawaii.
The world’s oceans are full of plastic, but nowhere is there as much of it floating as in the Great Pacific Garbage Patch – the great Pacific garbage patch. On an area about three times the size of France, waste from North America, South America and Asia is floating there. It is driven together by the North Pacific Gyre, a sea surface current that runs clockwise across the North Pacific.
Exactly how much plastic circulates in the Great Pacific Garbage Patch can only be estimated. Rough calculations speak of at least 80,000 tonnes. Or 1.8 trillion pieces of plastic (one trillion is a thousand billion). If you look at all the oceans together, the numbers are even more inconceivable: 86 to 150 million tons of plastic have accumulated in the world’s oceans. Every year, 10 million tons are added. That’s one truckload per minute.
Number of plastic parts in the ocean
Parts per square kilometer
510100100010’000100’000
Microplastics
Larger pieces
Whole Products
0,33 – 1mm1mm – 4,75mm4,75 mm – 200mm>200mm
North Atlantic Garbage Patch
Great
Pesticides, pharmaceuticals, heavy metals: There are a wide variety of pollutants that end up in the sea. But plastic is the most common of all. And probably also the most devastating: this was the conclusion reached by UN experts. This is first and foremost due to the longevity of plastic. It takes an estimated four hundred and fifty years for a plastic bottle that we use once to decompose in the sea. So it’s not surprising that objects from the 1960s were already found in the Pacific garbage patch. And plastic doesn’t disappear when it breaks down. It becomes so-called microplastics. These are plastic parts with a diameter of less than five millimeters, possibly the most harmful form of existence of plastic.
Animals are the first victims: no one knows the exact numbers, but it is likely that one million seabirds and more than 100,000 marine mammals die every year from plastic pollution. They get caught in ropes, swallow microplastics, mistake supermarket bags, toothbrushes and mobile phone cases for food.
Plastic causes a false feeling of satiety, clogs the digestive system and leads to internal injuries. In 2019, a young beaked whale was found dead on the coast of the Philippines – with 40 kilos of plastic waste in its stomach. In 2018, it washed a sperm whale lifeless and emaciated onto the Spanish coast – with 29 kilos of plastic waste in its stomach. Turtles, dolphins, seals: all are affected. It is assumed that there is hardly a marine creature that does not yet have plastic in its stomach.
But humans are also suffering: microplastics have already been detected in drinking water, sea salt and our blood. In the liver, kidneys, lungs, intestines and even breast milk. A few weeks ago, a study showed that the human brain today contains about a disposable spoon amount of plastic – 50 percent more than eight years ago. One reason could be that plastic is preferably deposited in fat-rich organs and crosses the blood-brain barrier.
In the high mountains of the Pyrenees and the Rocky Mountains, tiny plastic particles were found, which had probably fallen down with the rain. Chemical pollutants are deposited in the sea on microplastics, but plastic itself often contains pollutants, such as plasticizers and flame retardants. Fish, mussels and crustaceans ingest all of this, and it reaches us via the food chain.
Plastic waste pollutes beaches and coastlines, affecting tourism, and reduces fish stocks, which not only threatens the livelihoods of fishermen, but also threatens the main source of protein for billions of people. Coral reefs and other marine ecosystems are being destroyed, negatively impacting biodiversity and climate stability.
One of the biggest concerns, however, is that the toxins in microplastics are washed out during digestion and accumulate in animal and human tissue. Science is only just beginning to deal with such dangers. If you talk to researchers, they say that when it comes to plastic, we are now at the point where we were twenty years ago with climate change: people are gradually becoming aware of the seriousness of the problem, but much is still unfathomable.
The thing about plastic pollution is this: It concerns us all because it affects us all and we are all responsible for it. But none of us feels responsible, because the catastrophe is taking place in a space that belongs to no one: the vast sea.
But one felt addressed, a slender Dutchman named Boyan Slat. When he appeared in front of the media in San Francisco in September 2018, he looked like a bachelor’s student at the graduation ceremony with his twenty-four years, long brown hair, mirrored sunglasses and freshly ironed blue shirt. Sending a ship to clean up the Great Pacific Garbage Patch had been his idea. Very few believed that it could work.
From the deck of an escort boat, Slat watched with journalists as the Maersk shipping company ship left the port. He was exhausted and nervous, but he didn’t want to let it show. He had been working towards this day for five years, nothing could go wrong. He casually leaned against the railing, let himself be interviewed and photographed.
His non-profit company The Ocean Cleanup had collected about forty million dollars by then. The funds came from charitable foundations, the Dutch government and Silicon Valley billionaires such as Peter Thiel and Marc Benioff, but also from small donors. At the media conference, Slat said: “For sixty years, humanity has been throwing plastic into the oceans – from today we are getting it out again.” A sentence made for the history books. Provided that Slat would succeed.
In the first few weeks, everything went according to plan. The ship reached the garbage patch, and the crew suspended the cleaning system. The engineers at The Ocean Cleanup had given it the simple name System 001, but the crew affectionately named it Wilson – in reference to the volleyball in the film Cast Awaystarring Tom Hanks, who is lost in a storm.
Wilson was a 600-meter-long, floating barrier in a U-shape. At its lower end was a kind of carpet that reached three meters into the depth. The system was designed in such a way that the plastic parts were directed to the middle of the barrier, where they only had to be collected. From above, Wilson looked like a giant Pac-Man eating its way through the garbage.
System 001 — Wilson
The first prototype, Wilson, was to capture the plastic by means of a passive drive: it was moved 
only by the wind and currents.
600m wide
3m deep
The ingenious thing – or: supposedly ingenious – was that Wilson did not have to be pulled or steered, but drifted through the seas on his own, carried by wind, waves and currents. Apart from the diesel consumption of the transport ship that brought the garbage back to shore, it seemed to be an ecologically sound and, despite the crazy dimension of the clean-up operation, perhaps even an affordable solution.
Because Boyan Slat gets seasick at the slightest wave, he did not make the journey to the garbage carpet. He followed Wilson’s progress from The Ocean Cleanup’s headquarters in the Dutch university city of Delft. The company had grown to eighty employees in the five years since it was founded and was about to move to the city centre of Rotterdam.
For four months, Wilson drifted undisturbed through the North Pacific. Then suddenly no more: Shortly before Christmas, the barrier broke apart, an 18-metre-long section came loose. But that wasn’t the only bad news. The calculations, according to which the current would flush the plastic waste into the Pac-Man’s mouth, had turned out to be wrong. Wilson was a trash can that contained no garbage at all. Or at least far too little to make the effort worthwhile.
And it was a broken trash can on top of that. On January 17, 2019, the crew aborted the attempt and went ashore in Hawaii. Slat was desperate, as he tells me during a long conversation in Rotterdam in the fall of 2024: “We really thought it would work.”
Everything was still good then: maiden voyage of System 001 in autumn 2018.
Foto: Guillaume Beaudoin (The Ocean Cleanup)
The media spoke of a failure. Before the start of the project, they had celebrated Boyan Slat as the Messiah, now they dropped him. A headline in the Washington Post hit him hardest: “Experts warned that this floating garbage collector would not work. The ocean proved them right.” He was irritated by how easy it was for some people to badmouth an idea just because the first attempt had failed. “Don’t they know that this is exactly how innovation works?” he asked himself. You try something, fail, learn from it, repeat it and thus arrive at something that works.
However, Boyan Slat also suspected that nothing less than corrections work in the media. And he didn’t want to justify himself, he wanted to continue working. In the meantime, however, not everyone at The Ocean Cleanup believed in the idea anymore. Cleaning up a garbage patch three times the size of France – how could anyone have dared to do that?!
Slat sensed the skepticism. He set himself and the team a new goal: In four months, he wanted to go out into the Pacific again with the further development of System 001. His name? System 001/B.
2
Boyan Slat: Problem solver, not environmentalist
A sixteen-year-old sees more plastic than fish while snorkeling and sets out to change the world.
Every story begins with a question. The story of Boyan Slat began with this:
Why can’t we keep the oceans clean?
We know the answer: Because we are human. We enjoy the benefits of plastic, but when it comes to the consequences, convenience wins. Instead of recycling consistently or using alternatives, we accept the pollution of the oceans.
The special thing about Boyan Slat is that he was not satisfied with this answer.
He was sixteen when he saw more plastic bags than fish while snorkeling off the Greek coast. Back at school, he began to read up on the problem of plastic pollution. Together with his mother, a city guide, he lived in Delft near the Dutch North Sea coast (his father, a painter by profession, lived in Croatia). Boyan Slat had always been an outsider, a child who stuck his head in books and acted older than he was. A loner, a tinkerer, a nerd. In a way, it still is today.
“I’m curious,” he tells me when we meet at The Ocean Cleanup’s headquarters in Rotterdam. “More than that, I’m obsessive. If I’m convinced of an idea, I want to implement it.”
His schedule is so tight that my interview with him was arranged months in advance. Now he’s slightly late – he’s coming back from a trip abroad – which is why his assistant makes me wait in the lounge of The Ocean Cleanup. In a faceless office building on a busy roundabout, the company occupies several floors. It now employs one hundred and sixty people.
When Boyan Slat arrives, I don’t even notice him at first, so much has a huge painting on the wall captivated me. It shows a sea in many colors. I have the impression that I can see not only the surface, but also many thousands of meters deep down to the seabed. Slat stands next to me and says: “You can lose yourself in it, can’t you?”
The painting, he explains to me, consists of twenty layers of acrylic paint and six layers of fine oils for sealing and solidification. It comes from a young Dutch artist named Joshua van Leader, who worked on it for a year. In November 2022, not long after completion, he committed suicide, after which the painting The Ocean Cleanup was bequeathed.
The artist has called it “thalassophile”, from the Greek thalassa, which means “sea”. “Thalassophile” can perhaps be described as “devotion to the sea”. Van Leader himself once said: “It’s the perfect word to describe me, someone who loves the ocean.”
“Inspiration is not found in the negative, it is found in the positive.”
Boyan Slat, Problemlöser
A lover of the seas is also Boyan Slat. But that’s not why he took on plastic pollution. The reason is that the challenge appeals to him. Boyan Slat is not an environmentalist, he is a problem solver.
We talk about Hans Rosling, the late Swedish physician and author of the bestseller “Factfulness”, who described himself as a “possibilist”, a word creation of optimist and possible. Slat can identify with that. “I’m not so naïve as to believe that things will be okay by themselves. But I believe that they can be good if we put in the effort.”
I ask him what message he would print on a poster if he could. He thinks for a long time. “Don’t protest against things you don’t agree with, but work towards a future you agree with,” he says. And he explains what he means by that: “If you look at environmental protection, there is a triple negative. Environmentalists are negative in the way they think about the future. Not all, but many believe that the earth is coming to an end. Second, they believe that fear is the way to move the masses. And thirdly, their methods are also negative. They are against fossil fuels. They focus on the things that are bad, not the things that are good.”
I look at the painting again and have to think of my own obsession with the sea. The peace it triggers in me, but also the joy it gives my children. The sea is for everyone, I think. Slat continues:
“I would never have started The Ocean Cleanup if I believed that everything was pointless and that we were lost anyway. And I wonder whether movements like Fridays for Future really bring more good than bad to the world – or whether they might not lead to more indifference to the problem. It’s not as if we don’t know how bad the climate is. It’s more like there’s a lack of inspiration. Young people need inspiration to make a difference. But inspiration is not found in the negative, it is found in the positive.”
18-year-old Boyan Slat explains how oceans can clean themselves.
Video: TEDx Talks (Youtube)
Slat was eighteen when he first presented his solution to plastic waste – or what he thought was the solution at the time – to a larger audience. That was in 2012, two years after the snorkeling trip in Greece. He had finished school and was now studying aerospace engineering. He gave his presentation at a TEDx conference. It was available all over the world, a platform for innovative and inspiring ideas. One of the conditions: get to the point quickly.
Das konnte Slat. And he could do even more. Here was someone who was not interested in naming, but in solving problems. The people were enthusiastic. Slat did not declare war on the plastics industry (although he later repeated often enough that of course a lot has to be done in this regard), but announced a clean-up campaign. That was his promise. It was a tempting promise. Tidying up means doing something. It gives you a good feeling. You make the world a better place without having to do without anything.
The 600-meter-long barrier, which was dragged into the Pacific garbage patch six years later – in September 2018 – as System 001, no longer had much in common with the initial idea in terms of technical details. Except for the basic idea: to take advantage of the ocean currents. But then it turned out that not even that worked properly. When the crew of The Ocean Cleanup went ashore in Hawaii with hanging heads, the company was almost bankrupt. But Slat knew that now was not the time to ask investors for new money. The hype had died down, the attempt failed.
How did he manage to make The Ocean Cleanup a success despite this history of failure?
In Rotterdam, we are now sitting in a meeting room. Slat’s assistant brings salad, vegetables and quinoa from the buffet. Shortly afterwards she stops by again and admonishes him to have something to eat (I already have half of my plate empty). Slat, however, continues to speak without a break. “The problem with innovation is that new ideas are very fragile,” he says. “Out of a thousand young people who try something, nine hundred and ninety-nine fail. Not because the idea is bad. But because they are discouraged by the critical voices after the first setback or no longer raise enough capital.”
“Boyan has the ability to think both very small and very big.”
Matthias Egger, scientist at The Ocean Cleanup
Boyan Slat is different. He stuck with it. He thinks of The Ocean Cleanup when he wakes up in the morning, and when he goes to bed at night, he still thinks of The Ocean Cleanup. He allows himself twenty minutes of distraction a day: to read a few pages in a book before going to sleep. The thing Boyan Slat is working on is too big for him to allow himself to spend time on anything else.
He broke off his studies in aerospace engineering after the first semester. He is the only member of his research team without an advanced degree. Some of the scientists he hires are initially skeptical as to whether he is up to the task. But the doubts quickly subside.
That’s what Matthias Egger from Switzerland, one of the chief scientists of The Ocean Cleanup since 2018, tells me. He says: “Boyan has the amazing ability to think both very small and very big. You can have detailed conversations with him about technical subtleties, he knows about everything, has read every scientific paper – but he can also convince politicians and businessmen of his vision.”
Egger appreciates something else about Slat: his pragmatism. “That’s typical of the Dutch,” he says. “They are always thinking of a solution. They are aware that their idea may not be perfect. But they say to themselves: If you don’t like something, you have to do something about it. Because if you don’t do anything about it, you can’t complain.”
This was also the case in January 2019, when Slat told his people to ignore the critics. He has an easy time talking, thought Matthias Egger. Most of the criticism came directly from the scientific community. He often knew those who expressed themselves negatively personally.
“The problem at the beginning of a project is that you can hardly distinguish an idea that will work from an idea that won’t,” Slat tells me in Rotterdam. “The idea that leads to a great success and the idea that ends in a complete failure basically sound the same. That’s what makes it so difficult to find out which one is the right one.”
He is not finished yet.
“I asked myself: Who is actually criticizing the critics? It was as if they had carte blanche. They could say what they wanted. They had no accountability. Nobody goes back to them today and asks them what they think about The Ocean Cleanup.”
In June 2019, another ship of the Maersk shipping company set course for the Pacific garbage patch. This time from Vancouver Island. In tow: System 001/B, the further development of System 001.
System 001/B
The second version of Wilson had a brake parachute that slowed down the system. This should make the plastic drift more quickly into the collection zone.
999m wide
3m deep
Quelle: The Ocean Cleanup
In July 2019, the crew managed to catch their first catch: they pulled two large bags full of garbage out of the water, including centimeter-sized plastic pieces, but also bulky canisters. It was a special moment far out in the void, two thousand nautical miles from the nearest coast. When the bags were on board, the crew gathered and began to rummage through the garbage almost reverently, men in mirrored sunglasses and glowing safety vests. Someone filmed everything. You could see the relief in the people’s eyes: it worked.
The first catch with System 001/B in the Pacific garbage patch.
Video: The Ocean Cleanup (Youtube)
Shortly afterwards, Boyan Slat also learned about it. And then it didn’t take long again until it was clear that this would not be enough. System 001/B was not a success, only a start. Because as slowly as it collected garbage, it would have taken seven hundred or even eight hundred such barriers to clean the Great Pacific Garbage Patch.
Slat wondered: “Why don’t we just pull the system ourselves with ships?” It was the moment when he said goodbye to the last detail of his original idea: the idea that garbage could be collected passively. But being right is not important to him. He doesn’t have to be right. He wants to do the right thing.
3
A brief history of sculpture
Cheap, practical, diabolical: The invention of plastic was first a blessing, then a curse.
Anyone who has been dealing with the pollution of the world’s oceans for a while can hardly see plastic as anything other than garbage. And yet there is a reason why we produce it in such quantities: plastic is ingenious. It is light, robust, waterproof, durable. It is inexpensive to manufacture and versatile. Plastic saves lives and makes life easier, we use it to build medical devices, airplanes, electric cars, make clothes, toys and cosmetics.
But it is precisely the properties that make plastic so valuable that are a problem when it comes to disposal. Worldwide, only 14 percent is recycled correctly. And a third, 32 percent, ends up directly in the environment.
The dimensions are gigantic: Every year we produce 400 million tons of plastic – 50 kilos per person, almost 40 percent more than ten years ago. And it’s getting more and more. Three-quarters of the plastic ever produced is now waste, often in the form of disposable packaging. If we continue like this, the amount of plastic waste will triple by 2060.
Global plastic waste
In tonnes per year
1248
TotalImproperly disposed of
Nile Delta
Jakarta
Jakarta
Tokyo
Los Angeles
Tokyo
New York
Tripoli
Manila
Quelle: Future scenarios of global plastic waste generation and disposal
There was a time when people looked at this material in a completely different way. Plastic was a promise. Not the beginning, but the end of all problems. After the Second World War, plastic marked the beginning of the consumer age, and the future was built on plastic. As early as 1941, two British chemists – Victor Yarsley and Edward Couzens – imagined how we would one day live in the “plastic age”. They wrote: “The ‘plastic man’ will come into a world full of colours and bright surfaces, a world in which man, like a magician, produces what he wants for almost every need.”
They imagined how this person would grow up, surrounded by unbreakable toys, rounded corners, indestructible walls, dirt-repellent fabrics and lightweight cars. The humiliations of old age are alleviated by plastic glasses and prostheses until he dies, whereupon he is buried “hygienically enclosed in a plastic coffin”.
I come across Yarsley, Couzens and their plastic people in the excellent book “Plastic: A Toxic Love Story” by author Susan Freinkel. I am amazed at how accurate the prophecy of the two chemists was. Except for one detail: the problems. They didn’t see them. They thought plastic would democratize the world. And in a cynical way, this was even true: plastic was soon everywhere – even in the poorest areas of the world.
But it is precisely these areas that account for the largest share of marine pollution today. It is true that rich countries produce much more plastic waste per person than poor countries. But in rich countries, the majority of this waste is incinerated, recycled or sent to well-managed landfills, while low- to middle-income countries struggle to do so.
The path of plastic
How plastic gets into nature
Production
Service life
Decomposition
Nature
Water
Ocean
Wind
Microplastics
Correct disposal
in landfills or recycling
Deposit
Larger plastic parts
Improper disposal
If you look at the incorrectly disposed of plastic waste per capita – this includes materials that are incinerated in open pits, dumped into seas or open waters, or disposed of in unsanitary landfills and landfills – Brazil is ahead of Gambia, India, China and Morocco. This was the result of a study published in 2021 in the journal Science Advances.
The following figures also come from there: At 65 percent, Asia is by far the largest cause of improperly discarded plastic waste of all continents, followed by Africa (22 percent) and South America (8 percent). Comparatively successful waste management is carried out in North America, Europe and Oceania, while the three continents together are responsible for just under 5 percent of the world’s incorrectly disposed plastic waste.
Asia and Africa as the largest polluters
Share of improperly disposed of plastic waste worldwide, 2019
Asia
64,6 %
Africa
22,2 %
South America
8,0 %
North America
3,1 %
Europe
1,9 %
Oceania
0,2 %
Quelle: Our World in Data
Maybe it’s a bit late to ask this now, but better late than never: What is plastic anyway?
When we talk about plastic, we actually mean plastic. This is a material that does not exist in nature, but which is artificially produced from substances that exist in nature. Above all, it has to be said, from one substance: crude oil.
Crude oil is a natural substance. It consists of organic material and has been stored deep in the earth for millions of years. When it is pumped out of the earth and heated, the precious gasoline is obtained. When further heated, this is called cracking, the gasoline splits into its components, and ethylene, propylene and other compounds are formed – the basic material of plastic.
The discovery of plastic was a little more than a hundred years ago. In 1907, the Belgian-American chemist Leo Baekeland experimented with the substances phenol and formaldehyde and found that they polymerize into a synthetic resin in an exothermic reaction – when more energy is released than has to be supplied. A dark-coloured, robust material was created: Bakelite. It was the first truly synthetic plastic and in certain areas replaced shellac, a resin secreted by scale insects and used for electrical insulation in the early 20th century.
However, plastic did not have its breakthrough until the middle of the last century. In the Second World War, the new plastics had been monopolized by the military, now the huge production potential had to go somewhere. A few months after the end of the war, thousands of people queued up at a plastics fair in New York to see the new promises. “Nothing can stop plastics!” the organizer shouted to the people. [You can read an article on the triumphal march of plastic here.]
That’s right!, Boyan Slat could have called back decades later, when he looked at images of the Great Pacific Garbage Patch more often between July and October 2021 because it tested the latest development of The Ocean Cleanup: System 002, called Jenny, like the boat in “Forrest Gump”, another Tom Hanks film.
At that time, Slat had been working on nothing else for eight years, a third of his life, and yet his garbage chute had only collected 7,300 kilos of garbage. This corresponds to 0.0091 percent of all garbage floating in the Great Pacific Garbage Patch. “Pretty depressing,” Slat said.
4
The Swiss at Boyan Slat’s side
An environmental scientist from Appenzellerland who not only wanted to understand environmental problems, but to solve them right away.
When Matthias Egger first went out for the Great Pacific Garbage Patch, he already knew that the claim that the garbage patch was even visible from space was not true. And yet he was amazed when he looked around him and at first saw nothing. He looked more closely. Then he recognized it too, even from the deck, ten meters above the water. Every few minutes something drifted by: an umbrella handle, a laundry basket, a toy gun. As soon as he saw the first object, he noticed more and more as far as the eye could see. He began to calculate. What would this mean for the entire area, which is three times the size of France? He felt dizzy.
We teach our children the polluter-pays principle: If you make garbage, you have to clear it away. In the sea, we have forgotten this rule.
Photo: Dan van der Kooy (The Ocean Cleanup)
The Great Pacific Garbage Patch is not a garbage patch in the literal sense. There is not litter across the board, but there is a lot of garbage there – more than anywhere else in the world’s oceans.
If you look at the weight of the waste (at least 80,000 tonnes), the large, clearly visible objects make up 92 per cent. When it comes to quantity, it’s the other way around: 97 percent of the 1.8 trillion pieces are microplastics, smaller than half a centimeter, only recognizable when you launch the dinghy, as Egger then did. When he got into the boat, he saw countless white dots around him. Like a starry sky, he thought.
The North Pacific Gyre
How the currents distribute the plastic in the sea
North Pacific
Gyre
WesternGarbagePatch
Great PacificGarbagePatch
North Equatorial Current
Equatorial countercurrent
Japanstrom
Nordpazifikstrom
California
Stream
Parent current
Quelle: Ocean Tracks
As an environmental scientist, Egger had often gone to sea before his time at The Ocean Cleanup. Week-long expeditions took him through the Baltic Sea, the North Sea, the North Atlantic and the Black Sea. He loved these journeys on the open sea, the sixteen to twenty-hour working days. He enjoyed being surrounded by water, accompanied by dolphins, whales, sharks and turtles.
But this was something else. In the Great Pacific Garbage Patch, he no longer studied marine ecosystems or climate phenomena. He researched garbage. He spent two months in the North Pacific at the end of 2018, followed by another month at the end of 2019. He collected data to help The Ocean Cleanup clean up the garbage patch. So far away from civilization that no one was closer to him and his crew than the astronauts of the ISS, hundreds of kilometers above them in orbit.
Researching marine litter: Swiss environmental scientist Matthias Egger.
Egger grew up in Appenzellerland, then lived in the Netherlands and Denmark for ten years, and now lives with his family in St. Gallen. Everything in his life indicated that he would have a stellar career at the university. But then he dropped out – shortly after completing his doctorate. On his research trips, he had to watch how the condition of the oceans deteriorated year after year. “It is of course important to continue to investigate the negative effects of our human actions on the oceans,” he tells me at a meeting in a St. Gallen café at the end of 2024. “But for me personally, that was no longer true, I wanted to understand the problems, but even more I wanted to contribute to a solution.”
The history of The Ocean Cleanup is also a history of the relationship between theory and practice. When Slat started, there were countless theoretical calculations and modelling on currents, wind speeds and plastic waste volumes. But Slat and Egger quickly realized that reality was more complicated than the models.
In Rotterdam, Boyan Slat tells me: “You often hear that ten million tons of plastic waste end up in the sea every year. And then you go out to sea and try to find this garbage. But you can’t find him. Or somewhere completely different than you thought.”
So there is a discrepancy between model and reality. Slat again: “When you’re trying to solve a problem, you can’t just pretend that the model is reality.” The model is not reality, it is an approximation of reality. The two may be similar, but they are never identical. And at the same time, both are needed: a theory to approach the problem at all, and a practice to test the theory. And, in the best case, to solve the problem.
And then came System 002. Jenny. That was in the summer of 2021. The biggest innovation was that an active instead of a passive propulsion system was now used. Jenny did not drift rudderless through the Great Pacific Garbage Patch like Wilson, but was pulled by a ship at each end of the barrier. This allowed the system to be moved faster than the plastic stream, and it was easier to maintain a stable speed difference to the plastic.
Nevertheless, it remained complicated. Critics were concerned that not only plastic would be caught, but also fish and other creatures. So Slat wanted to proceed particularly carefully. The first test was completed after just two hours, then the catch was examined: 100 kilos of plastic waste, hardly any bycatch. Slat did the math: If you worked around the clock, you would lose 1200 kilos or 1.2 tons per day. This is exactly what he had hoped for from a system of this size.
The criticism of those who fear that The Ocean Cleanup’s clean-up operations could cost the lives of countless animals has not completely died down to this day, even if the figures have long since disproved them.
- Firstly, according to Matthias Egger, it has been shown that the bycatch rate is much lower than that of fisheries, where often half of the creatures caught are unsuitable for consumption. In The Ocean Cleanup, 99.7 percent of the catch in the Great Pacific Garbage Patch is actually plastic.
- Secondly, 80 percent of the creatures collected are invasive species, i.e. those that don’t really belong there: crabs, soft corals, lichens.
- Third, the garbage patch poses a threat to one of the largest marine protected areas in the world – the Papahānaumokuākea Marine National Monument off Hawaii. On 1.5 million square kilometers, it provides a habitat for an incredible variety of corals, fish, birds, marine mammals and other plants and animals. The more plastic is removed from the Great Pacific Garbage Patch, the less of it enters the marine reserve.
- Fourth, the negative impact of plastic on marine life has been shown to be greater than the potential impact of cleanup.
Another test lasted two days. At home in Rotterdam, Slat woke up on the morning of the third day and looked at his cell phone. He had missed dozens of calls. He opened Whatsapp – and there was this photo. “I still get goosebumps when I think about it today,” he says. On the deck of the ship that collected the garbage was a huge pile of plastic. Many times more than 100 kilos – Slat recognized that immediately. It was not joy what he felt. It was relief: Jenny worked.
But Slat and Egger also realized that the garbage patch is not as homogeneous as the models have calculated. Even here, in this largest garbage dump in the world, there is not the same amount of garbage everywhere. If they wanted to work efficiently, they had to be able to react flexibly and follow the garbage. So they developed computers and models that helped them identify areas with particularly high plastic density – and guide Jenny there.
The first trip lasted six weeks in the summer of 2021, then they returned to Vancouver Island and a new crew took over. When Jenny was last used in the summer of 2023, 282,787 kilos or just over 282 tons of plastic waste had been fished out of the sea. That was already significantly more than the 7300 kilos with Wilson. But it was still far too little if you wanted to remove the whole garbage patch. More Jennys were needed. And bigger ones.
This idea is not garbage: Fish plastic out of the sea with the help of floating barriers.
Foto: The Ocean Cleanup
Jenny’s successor is called Josh, named after the boy in the Tom Hanks film “Big”, who suddenly lives in an adult body as a child. That fits. Because System 03 – with only one zero! – is larger than the previous ones. The barrier of System 001 was 600 meters long, that of System 002 was extended from 800 to 1600 meters over two years. The barrier of System 03 / Josh measures 2500 meters and reaches not three, but four meters into the depth.
System 03 — Josh
Computer models locate the densest waste zones and thus show where the cleaning systems are ideally used.
2200m wide
4m deep
Sammelndes Plastiks
Plastic Removing
Recycelndes Plastiks
The garbage enters the collection zone because the collection system and the plastic floating around have a different speed.
Once the containment zone is full, it is disconnected from the system and brought on board where it can be emptied. Then the collection zone is reopened and cleaning continues.
When the containers on board are filled with plastic, they are brought ashore for recycling. The sale of products made from the recycled material is part of The Ocean Cleanup’s financing.
Containment zone
Quelle: The Ocean Cleanup
Josh, it can already be said, is a success. When the system was brought to the port of the Canadian city of Victoria in October 2024 for a general overhaul, the total catch had almost doubled within a year – to just under 500 tonnes. Compared to the total amount of garbage floating in the Great Pacific Garbage Patch, this is still rather low: not even one percent. But you could also say that almost one percent of the problem has already been solved.
5
The Problem Behind the Problem
Rivers are the arteries that transport the plastic into the sea. How to clean them?
To understand how this initial (and years-long) story of failure could become one of the most inspiring environmental initiatives ever, we need to look back.
On October 27, 2019, Boyan Slat entered a floodlit workshop in the port of Rotterdam, addressed the audience and solemnly said: Two things are needed to clean the oceans. First, capture the plastic waste. And secondly, to ensure that no new plastic waste gets into it.
“We don’t want to be the garbage men of the oceans, although that would be a profitable business model,” Slat said. “Our goal is to put ourselves out of business. That’s why we started a secret side project four years ago to find a solution to the other side of the equation. They know how we want to approach the first part of the task. Now I’ll show you what our plan for the second part looks like.”
Behind him a curtain was lifted, and the gaze fell on the harbor basin, in which something that looked like a ship was floating. It was called “interceptor”, which can best be translated as “interceptor”, and was supposed to do just that: intercept plastic waste before it ends up in the oceans.
Rivers that flow into the sea are the number one plastic waste transporter, such as a tributary in Kingston, Jamaica.
Foto: The Ocean Cleanup
Five years later in the meeting room of The Ocean Cleanup: Boyan Slat still hasn’t touched his lunch (while I wonder if there might be dessert). He remembers the presentation of the Interceptor, of which you can find countless videos on YouTube today because it inspired so many people. And he tells how he feared that the credibility of The Ocean Cleanup would suffer if he made a new promise, while not even the system for cleaning up the Pacific garbage patch was working properly. Hence the secrecy.
But now he did everything he could to impress the audience. By five years, he announced, the Interceptors would be in use in a thousand rivers. Rivers “are the arteries that transport the garbage from the land to the sea”. A vacuum cleaner for the rivers – that’s what Slat called the Interceptor. And disposing of the garbage should be as easy as a vacuum cleaner, the only work step that still had to be done by human hands in the otherwise autonomous system powered by solar energy.
It doesn’t stay on land
All these rivers are washing plastic into the sea, in kilos/year
5025050010002500
Share of plastic washed into the sea worldwide, 2019
Slat asked the audience to take a closer look at the Interceptor in the workshop. The number 001 was not emblazoned on the side, as one might have expected. It said: 004. Slat smiled. “You know what that means, don’t you? That three systems are already in use.” Then three broadcasts were recorded – from Indonesia, Malaysia, Vietnam. Everywhere there was already an interceptor doing its work. You could see what Slat had previously demonstrated in the factory hall with thousands of small squeaky ducks: that the Interceptor also worked in nature. A barrier intercepted the washed up garbage and directed it to the interceptor, where it was lifted out of the water by a conveyor belt and then transported into one of six containers.
There is something deeply calming about watching garbage being collected that would otherwise simply be washed into the sea. Especially when you know what it looks like in these rivers. There, not every few minutes a larger plastic object drifts by, as in the Great Pacific Garbage Patch – in many places you can hardly see the water because of all the garbage.
Purification system in Ballona Creek in Los Angeles: After the first winter, the city government announced that plastic waste on the beaches had been reduced by 75 percent.
Foto: The Ocean Cleanup
The presentation met with great interest, so that further models of the “vacuum cleaner” were soon put into operation. Interceptor 007, for example, was shipped to Los Angeles. After the first winter, the city administration announced that plastic waste on the beaches had been reduced by 75 percent.
But then it got complicated again – for the same reason that it had become complicated in the Great Pacific Garbage Patch: because problems appeared in reality that had not been taken into account in the models.
For example, it was long assumed that the longest rivers also carry the most plastic waste into the sea – especially if they flow through large and densely populated areas with poor waste management. So Amazon, Nile, Mekong, Ganges or Yangtze. In 2017, a study claimed that only 5 rivers are responsible for 80 percent of marine pollution. Another study from the same year came to 162 rivers.
In fact, both studies were wrong. Not 5 and not 162 rivers are responsible for 80 percent of the pollution, but 1656 rivers. “We were wrong,” Slat tells me. “Most of the pollution comes from small rivers in coastal cities in middle-income countries. We concentrated on the big rivers, but now understood that the garbage often doesn’t even reach the sea there because it washes up on the shore on the way.”
In 2021, a study confirmed the findings. Apart from the quality of waste management, three factors in particular contribute to a river taking a lot of plastic with it:
Proximity to cities: Large amounts of plastic come from urban areas with many sealed surfaces that discharge water and garbage directly into the rivers. Especially small but heavily polluted rivers in metropolises such as Jakarta or Manila contribute significantly to pollution.
Short distance: Rivers that run close to a coast transport a lot of plastic into the sea.
High rainfall: Rain washes plastic into rivers and accelerates transport to the sea.
When Boyan Slat takes stock with me in the fall of 2024 – five years after the announcement on the factory floor – a thousand interceptors have not been installed as hoped. Not even five hundred. Not even a hundred. In these five years, only twenty-one interceptors have been put into operation.
It turned out that the interceptor concept is not applicable to all rivers. No two rivers are the same, each requiring individual adjustments. Sometimes the width of the river is a challenge, then the flow speed or the sheer amount of waste. Some rivers transport so much garbage that it is more efficient to erect a more robust barrier and take the waste out with shovel excavators instead of first transporting it into the containers of an interceptor.
Never sea garbage: An interceptor barricade in the Rio Las Vacas in Guatemala.
Foto: The Ocean Cleanup
There are two ways to look at these setbacks. You could say that Slat failed because he fell far short of his expectations. Or you could say that they are not setbacks, but insights. Slat has proven – albeit in a roundabout way – that it is possible to clean rivers. Just as he proved that it is possible to clean the Great Pacific Garbage Patch. It involves effort and great effort, but it is possible. We just have to want it.
The Ocean Cleanup keeps an exact record of the amount of waste collected. We already know the almost five hundred tons that have been fished out of the Pacific so far. But what about the rivers? In five years, says The Ocean Cleanup, more than twenty million tons of waste have been prevented from drifting into the oceans.
In these two ways, the rivers are freed from plastic
Barriers
The plastic floating in the river is stopped by barriers and collected in containers.
Interceptor
A tugboat brings the full containers to the shore, where they are unloaded and the plastic is sent for recycling.
By anchoring the barriers to the bank and never crossing the entire width of the river, a path is left free for shipping.
A conveyor belt lifts the garbage out of the water and transports it into the containers located on the Interceptor.
A tugboat picks up the full containers and brings them ashore.
Variants
The collection ship works autonomously and is powered by solar power.
Reinforced barriers have been developed for the annual “plastic tsunamis”, over which less plastic is washed away.
A solution has also been found for shallower waters: a shallower barrier that does not cause structural damage to the riverbed.
Quelle: The Ocean Cleanup
An incredible number. An incredible success story. Despite the relativization that Slat himself makes in our balance sheet discussion. “You have to know,” he says, “that you can’t compare a kilo removed from a river to a kilo removed from the Great Pacific Garbage Patch. Most of the waste that enters the sea via a river does not stay there for very long. On average, 97 percent of this waste is washed back to the coast within a year.”
In the Great Pacific Garbage Patch, clean-up work has been dormant since Josh was brought to the port of Victoria in the fall of 2024. The engineers at The Ocean Cleanup have some ideas for further developments – especially with regard to detecting plastic hotspots. Slat wants to give them until the end of 2025 to do so.
The company has now published an estimate of how long it would take and how much it would cost to remove between 80 and 90 percent of the garbage from the Great Pacific Garbage Patch (100 percent will never be achieved, that was always clear): ten years and just under seven billion Swiss francs.
Is that a lot? Is it little?
By comparison, Switzerland spends a good three billion francs annually on the disposal of all waste. If you look at it this way, the seven billion for the Great Pacific Garbage Patch would be rather little.
The criticism that Boyan Slat hears most often is that he fights symptoms instead of causes. That his clean-up campaign distracts from the real problem – namely that we produce too much plastic and do not dispose of the waste in an environmentally friendly way.
Slat does not deny this. He says: “If I could choose, I wouldn’t let the plastic waste get into the sea in the first place. But we are sixty years too late for that.” He thinks for a moment. “I don’t see what we do as a substitute for something else. I consider it a complement. And I don’t think that our work distracts people from the real thing. On the contrary, I believe that we are making people aware of it. Our experience is that wherever we install an Interceptor, awareness of the plastic problem increases.”
Boyan Slat is not a dreamer. Nor is he a moralist. He is a pragmatist. In contrast to the mission in the Great Pacific Garbage Patch out in the Pacific, where no one feels responsible for the garbage, he and his team never take action on their own with their river system. It needs the will and financial resources of the local authorities.
Depending on the model, the acquisition costs for an interceptor range from 600,000 to 700,000 francs. The Ocean Cleanup takes care of the installation and implementation, then the system is handed over to the local people, who take care of the maintenance and, above all, the regular emptying of the containers.
In Kingston, Jamaica, all urban tributaries to the Caribbean Sea were soon equipped with an interceptor. The hope is that this will massively reduce plastic waste in the water. In Guatemala, a solution seems to have been found for the Río Motagua, one of the most polluted rivers in the world. The goal is to get the Gulf of Honduras, which is bordered by the coasts of Belize, Honduras and Guatemala, completely free of plastic. And in the megacities of Jakarta and Mumbai, city governments are also expressing interest in clean-up campaigns with The Ocean Cleanup.
Panama City is even further along: The Bay of Panama is highly endangered by plastic pollution. To relieve them, the seven most important rivers will get an interceptor.
But the news that gives the most hope comes at the beginning of March. It shows how quickly things can suddenly move forward if you survive the time in which you fail, doubt, struggle. A record was recorded: 1,274,000 kilos of waste collected since the beginning of the year. This is almost three times as much as in January and February 2024.
Boyan Slat and The Ocean Cleanupour problem with plastic. There is a possibility that they will buy humanity some time in the next few years to look for a solution.
Bruno's point of view 