Boyan Slat wants to clean the world’s oceans of plastic, and he’s come up with a technological fix — a system of floating barriers in the middle of the ocean he hopes to deploy next year.

The plan is to scrub the Pacific garbage patch — a huge area between Hawaii and California where litter, mainly plastic, has concentrated because of marine currents forming what scientists call gyres — within five years.

The idea has made the young Dutch entrepreneur a star. What started as a high school project has now raised $31.5 million from various philanthropists, including Silicon Valley mogul Peter Thiel. He’s received vast amounts of media coverage, held the obligatory TED talk, and last week wowed a ballroom filled with selfie-taking enthusiasts.

The United Nations named him a Champion of the Earth.

The problem?

Many experts question the project backed by Slat’s Ocean CleanUp foundation. Some are doubtful about its ability to fulfill its basic premise — scooping up plastic — as the project has yet to deploy an operational prototype.

“Cleaning up debris in gyres is nonsense,” Francois Galgani, an expert on marine litter at French research institute Ifremer, warned at a recent workshop on marine litter in the European Parliament.

Sailing to the middle of the ocean to clean up debris represents a very expensive and technology intensive solution to a very small part of the problem, experts say.

Under the surface

Contrary to common misconceptions, most of the debris in “plastic islands” is in the form of tiny bits that can’t be seen from a boat. Only 1 percent of marine plastic is found at or near the ocean surface, while most of it sinks to the sea floor, according to a report by consulting firm Eunomia, which works for the European Commission on the issue.

Beaches, for instance, present much higher concentrations of plastic litter, at 2,000 kilograms per square kilometer, compared to 18 kilograms per square kilometer in the North Pacific patch.

But Slat defends his idea.

“It may be just a small percentage of the total plastic, but it is the percentage of plastic that does all the harm,” Slat told POLITICO. “Most life is at the surface. When it is at the surface the plastic imitates other life,” leading to marine species ingesting massive amounts of plastic.

The shaggy-haired 22-year-old, who favors Silicon Valley-style entrepreneur chic of black narrow-cut jeans and leather high-tops, insists his scheme will work. Ocean CleanUp plans to catch plastics by using U-shaped buoys with plastic skirts that will channel the debris toward a collecting system.

“What we are about to show you looks like nothing you have seen before,” he told his fans on May 11.

Ibrahim Thiaw, the United Nations Environment Program’s deputy executive director, called Slat “such an inspiration,” adding: “About the technology, I don’t know as of yet. We hope it will work.”

That’s what worries skeptics.

“They haven’t showed in any real-world test that this will actually work,” Kim Martini, a physical oceanographer at the University of Washington in Seattle, told POLITICO. Martini published a critical review of the project’s feasibility study in 2014 on Deep Sea News, a marine science blog.

While the Ocean CleanUp changed the design of its system since then, Martini said it still hasn’t properly answered the core question: “Will it actually clean up the plastic or just create another giant floating marine debris?”

Scientists also worry whether the system risks endangering marine life. “The most stinging argument [against it] and he will have to solve it, is that if he collects plastic he will collect everything that goes with it: algae, tiny turtles … this is all going to accumulate,” Galgani said.

Slat acknowledges his project is still experimental, but is confident that his team — which critics agree includes many renowned professionals — will be able to overcome technical challenges.

“Until we actually do it, it is guess work,” he said. “For the critical side it is a guess work. For our side that it wouldn’t do damage, it would also be guess work. The first operational system that we will be deploying within 12 months, it is really a test case.”

Many experts don’t question Slat’s good intentions, but they say he is over-promising. “The way they communicate to the public is pretty overblown,” Martini said.

A global problem

Their issue is that it’s sexy to offer a quick-fix solution to the problem of ocean plastics. The scale of the challenge was underscored this week when researchers reported back from Henderson Island, an uninhabited coral atoll in the remote South Pacific. They found 38 million pieces of plastic — 18 tons — the highest concentration of such trash in the world, thanks to ocean currents which spit the garbage up on land.

But the solution proposed by scientists and NGOs is actually pretty boring and bureaucratic — preventing plastic litter through better waste policies and product design. That’s something the EU hopes to do through its upcoming Strategy on Plastics.

The idea of cleaning up is “extremely catchy,” said Dustin Benton, policy director at environmental think tank Green Alliance, but risks being “a distraction” from the real solution.

Slat dismissed this. “When I started the Ocean CleanUp everyone told me ‘there is no way you can clean it up and the best thing you can do is not making it worse,’” he said. “I just thought this was a very uninspiring message.”

“It is not either or,” Slat said. “Saying that we should use less plastic or stop consumption” is like “trying to swim against the current.” Instead, Slat thinks, people should try to “funnel the human entrepreneurial spirit.”

“It is very much aligned with how the system works: not trying to fight the ocean but moving with it.”