When Boyan Slat observed more plastic bags than fish while diving in Greece as a teenager, it triggered a mission that would swell into one of the world’s most visible environmental cleanup campaigns.
The 31-year-old’s organisation, The Ocean Cleanup, has removed more than 50,000 tonnes of plastic from rivers and waterways since it evolved from the Ted Talk that went viral in 2012, and is now scaling up a plan that Slat claims could clean the ocean within a decade.
But as the group expands its river cleanup operation, questions remain over whether its approach targets the right part of a complex crisis.
Slat’s strategy rests on a simple premise: stop plastic before it reaches the ocean.
Using artificial intelligence-powered cameras mounted on bridges, The Ocean Cleanup has mapped waste flows across hundreds of rivers, concluding that just 1 per cent of the world’s rivers account for roughly 80 per cent of ocean plastic pollution.
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We’re now cleaning an area of ocean the size of a football field every five seconds.
Boyan Slat, founder, The Ocean Cleanup
That insight has driven its deployment of solar-powered “interceptors”, systems designed to capture waste in rivers before it spews into the sea.
The organisation is now active in more than 20 rivers across 10 countries and aims to expand to 30 cities by 2030 – through its flagship 30 Cities programme – backed in part by US$121 million from The Audacious Project, a funding initiative backed by TED Talks.
Slat argues that rivers offer the fastest and cheapest intervention point.
“If you work on rivers, you know that every piece of plastic that we take out would’ve gone into the ocean,” he told Eco-Business in an interview after an event hosted by consultancy The Matcha Initiative at the Singapore Sustainability Academy in April. “That’s the highest leverage.”
By contrast, upstream solutions are far more resource-intensive and slow-moving, he argued.
“Waste collection already costs about half a trillion dollars a year globally. That has to triple or quadruple,” Slat said. “What we’re doing is a rounding error compared to that.”
For about US$100 million a year, including the build-out costs of the river interceptors, systems and infrastructure, “we can get clean oceans,” said Slat, arguing that cleaning the oceans costs orders of magnitude less than the damage being caused by aquatic trash.
Crucially, the interceptor model now works, having been trialed many times across many different rivers. Early attempts to cleanup the Great Pacific Garbage patch, the largest accumulation of plastic in the open ocean, proved technically almost impossible – and drew derision from sceptics.
Slat recalls a news headline in the Washington Post from 2019 that read: ‘Experts warned this floating garbage collector wouldn’t work – the ocean proved them right’ after his trash collection device in the Pacific broke into two.
“For eight years we didn’t collect any plastic. The early years were about understanding the problem, doing the research, and going through failures,” Slat said.
An interceptor deployed on a river in Guatemala. Image: The Ocean Cleanup
A “quick fix” – or a distraction?
The aerospace engineering graduate is clear about how he sees The Ocean Cleanup’s role: not as a replacement for systemic reform, but as a stopgap.
“I wish our interceptors would not be necessary,” he said. “But fixing upstream systems will take decades.”
In the meantime, river interception offers what he calls a “quick fix”, one that could cut ocean plastic in years rather than decades.
The organisation estimates that deploying systems across the most polluting rivers could reduce global plastic flows by up to a third by 2030.
But critics argue that this framing risks oversimplifying a complex problem, and diverting attention from the root causes of plastic pollution, including rising production driven by the petrochemical industry.
According to a report by Pew Charitable Trust, plastic production is projected to double by 2040, from 2020 levels.
“I don’t see any other way in which we could have a material impact on the inflow in a matter of years,” he said. “If anyone has a better solution, I’d love to hear it.”
He frames the debate as a choice between idealism and pragmatism.
“There’s the root-cause philosophy – which is usually the most sustainable option long term – and then there’s the question of where you can have the biggest impact, fastest,” he said.
But global plastic production now exceeds 460 million tonnes annually, and is projected to grow. This raises questions about whether downstream interventions can keep pace with the damage being done by plastic pollution.
A smaller problem?
Another point of contention is the scale of the problem.
While widely cited estimates have suggested that up to 8 million tonnes of plastic enter the ocean each year, Slat argues that newer data – including The Ocean Cleanup’s own research – points to significantly lower figures.
“Our latest estimates are in the order of hundreds of thousands of tonnes, up to maybe one and a half million,” he said.
That revision reflects improved measurement of river flows, he added, after years of relying on broad modelling assumptions such as those in the landmark 2015 study led by Dr Jenna Jambeck, an American environmental engineer.
But lower estimates do not mean a smaller problem, Slat said.
“One tonne of plastic can cause tens of thousands of dollars in damage per year,” he said. “The impact is still enormous.”
Research published in The Lancet last year estimated that plastics are costing US$1.5 trillion in health-related costs annually worldwide, with those costs projected to increase by 75 per cent by 2040.
Slat argues that overstating the scale of pollution can backfire, making the progress being made to tackle the problem seem insignificant.
An Interceptor deployed on a river in Bangkok. Image: The Ocean Cleanup
Funding, partnerships – and accusations of greenwashing
As The Ocean Cleanup scales up, it must navigate a funding landscape compromised by geopolitical turmoil and climate policy reversals.
Slat acknowledged that corporate sustainability commitments have become more sensitive to political headwinds. But he said demand remains strong, provided that projects are framed as investments rather than charity.
“If you pitch it as a CSR [corporate social responsibility] check-the-box, it’s difficult,” he said. “But if you show real return on investment, it becomes a different conversation.”
That includes partnerships with companies linked to plastic production. Slat takes a pragmatic view. “If anyone should be involved, it’s precisely those companies,” he said. “It’s more fair if the polluter pays.”
The key, he added, is scale – companies investing small amounts risk tarnishing their credibility. “If it’s just token money, it doesn’t help anything,” he said.
Can the oceans really be cleaned?
Much of The Ocean Cleanup’s work takes place in middle-income countries where rapid consumption growth has outpaced waste management systems.
Slat says river trash interception is not just an environmental intervention but a social one – operations create jobs in waste collection, sorting, and system maintenance.
“There are hundreds of people whose livelihoods depend on this work,” Slat said, pushing back against critics who say his work should focus further upstream.
But once collected, the waste is difficult to manage – often contaminated and therefore hard to recyclable. So much of it is landfilled, incinerated or used as fuel.
“Our ethos is to always do the best possible thing with the waste – recycling what we can, recovering value where possible, and ensuring that whatever we collect never leaks back into the environment,” he said.
Boyan Slat speaking at the Singapore Sustainability Academy in April 2026. The Ocean Cleanup is aiming its expand operations to 30 cities by 2030, backed by US$121 million from The Audacious Project. The organisation says that 1 per cent of the world’s rivers carry 80 per cent of plastic pollution. Image: Robin Hicks / Eco-Business
But perhaps The Ocean Cleanup’s boldest ambition is how quickly it says it can have impact.
Slat suggests that “clean oceans” could be within reach in about a decade.
By his own estimates, The Ocean Cleanup is currently intercepting just 2 to 5 per cent of global plastic pollution flows. Scaling that up will require rapid expansion, sustained funding, and cooperation across dozens of cities and governments.
Slat acknowledges that the goal is ambitious, but insists it is grounded in reality. “We’ve already done up to 5 per cent,” he said. “Who else has done that?”
The Ocean Cleanup’s approach reflects a broader debate about whether to prioritise immediate, high-impact interventions or more systemic change.
Slat insists that the two are not mutually exclusive.
“We’re not against upstream solutions,” he said. “But we focus on where we can have the highest leverage.”
For now, the focus is on rivers – and the belief that stopping plastic at key choke points can buy time for more profound change.
Slat insists that for communities seeing cleaner waterways and recovering ecosystems, the impact is already tangible – and that is reason enough to keep the funding flowing towards his mission.
