Viral videos show whales ensnared and sea turtles choking. Studies find some 70 percent of seabirds have ingested the waste. And a photo recently revealed that plastic has found its way to even the deepest reaches of the ocean. Straws, forks, shopping bags, nets and all manner of human detritus seems to be everywhere in what was once the endless, unspoiled sea.

The world has signaled its alarm with a wave of countermeasures: Several American cities have banned plastic straws. Chile this spring joined a growing list of nations forbidding single-use plastic bags. In late May, the European Commission directed its 28 member nations to outlaw throwaway plastics, in what one official called a “global race” to slow the synthetic tide.

And now, an audacious young Dutch inventor named Boyan Slat and his 70-member team have entered the final preparations for a mission to deploy an experimental device they say can capture much of the plastic that fouls the world’s oceans.

A model of Slat’s unique plastics dam passed a crucial trial run in the Pacific Ocean last week and returned to its home base in San Francisco Bay. Days later, the Ocean Cleanup Project said it had won a green light from the Dutch government to conduct operations in international waters. And this week, Slat plans to unveil progress on the first prototype of his invention to reporters in Alameda, California, showing off the ungainly, 2,000-foot-long floating screen that is scheduled to be towed into the ocean before Labor Day.

Its target? The Great Pacific Garbage Patch, the largest of multiple rotating ocean “gyres” that attract waste like giant drains. The Pacific gyre is a sprawling witches’ brew of man-made flotsam, lost fishing gear and invisible plastic particles, stretching across an area three times the size of France.

If the Ocean Cleanup’s floating screen survives the fierce north Pacific weather and successfully traps plastic, its creators plan to deploy 60 similar devices in a remote area between Hawaii and California. Slat’s team calculates that, within five years, the floating arrays can clean up half of the debris in the garbage patch. The Netherlands-based organization promotes it as “The Largest Cleanup in History.”

The Ocean Cleanup seemed big, brazen and bound to struggle when it was introduced in 2016 to Rick Spinrad, an oceanographer who was chief scientist at the National Oceanographic and Atmospheric Administration.

“But the more I dove in and got more and more detail, the more I changed my mind,” said Spinrad, now a professor at Oregon State University. “They are doing a very thoughtful well-designed process to get to where they want to go. That is why I am convinced they are going to have some success.” Just how much success, he said, remains to be seen.

An Ocean Cleanup prototype after its unveiling to the press on June 22, 2016 in The Hague, Netherlands. Michel Porro / Getty Images file

The Ocean Cleanup’s profile has been elevated by its media-genic founder and leader. Uncannily confident, Slat used a TEDx talk in 2012 in his native Netherlands to announce that a solution to one of the world’s most intractable environmental problems was within grasp. He would solve the problem. He was 18 years old.

Now, six weeks shy of his 24th birthday, Slat still thinks he has the answer. And he has been persuasive enough to win praise from kings and prime ministers, rock stars and the United Nations. He also has drawn a cadre of persistent critics, who say his plan is directed at the wrong end of the plastics life cycle and could harm the very sea life it is meant to protect.

Slat rejects the notion that the amount of trash is already too immense, and too widely dispersed, to capture. “We can do this,” he has said. “We must do this. And we will do this.”

‘Working with nature instead of trying to fight it’

Slat’s TEDx talk, delivered in his hometown, Delft, won him growing acclaim. In the video, he described how he believed plastic could be collected by harnessing the ocean’s most powerful forces — currents and waves.

“I thought, ‘Why don’t you use those forces of the ocean to your advantage?’” Slat said in a recent interview, posing the idea of letting the trash wash itself into a slow-moving barrier. “Working with nature instead of trying to fight it.”

The TED video drew more than 2 million views. In its immediate aftermath, Slat got thousands of emails urging him on. Then a freshman studying aerospace engineering at the Delft University of Technology, he felt he couldn’t continue in academia and pursue ocean cleanup at the same time.

“I asked him what his heart told him,” his mother recalled in a recent interview with a Dutch publication, AmbitiousMama.com. “He was silent for 10 seconds, swallowed and said, ‘I have to do this.’”

A little more than five years later, Slat has raised more than $40 million for his startup, assembled an engineering-heavy staff of 70 and worked through multiple design iterations, leading to the one now being assembled at the former Naval Air Station Alameda in California.The trajectory that seems so outlandish to strangers is slightly less so to those who have known Slat from childhood.

His father was a Croatian artist and his mother, who raised him, a Dutch-British consultant for foreigners relocating to Holland. Boyan’s tinkering began at age 2 and he was soon building treehouses and ziplines and experimenting with explosives. In his early teens he tried to remove moisture from ammonium nitrate, using the family stove. He triggered an explosion and a caustic fog.

At 14, he knew enough about water-propelled rockets to launch his own and enough about organizing to rally 250 people to a mass firing of the devices from a soccer field. The feat earned him a notation in the Guinness Book of World Records for “most water rockets launched simultaneously.”

At 16, Slat was on a family vacation to the Greek island of Lefkas when a scuba diving excursion delivered an unwelcome surprise. “I looked forward to seeing so many beautiful things,” he said, “but under the water it was basically a garbage dump, with more plastic bags than fish.”

He asked himself why such pollution couldn’t be cleaned up. “I couldn’t really stop thinking about that,” he said. The question became a school science project, which launched a mission.

Slat originally envisioned one massive boom, more than 60 miles long, blocking trash in the middle of the gyre, with ships arriving occasionally to haul away the mess.

That has evolved into a plan for multiple “arrays,” each consisting of a pipe-shaped float — sixth tenths of a mile to a mile in length — with a 10-foot-tall screen of impermeable synthetic textile hanging beneath the surface. The crescent-shaped screens are supposed to allow sealife to swim under or around. A drift anchor, dragging in deeper and slower sub-surface currents, is intended to slow the screen enough for it to trap plastic forced into the crescent by the faster currents along the surface. A ship would then be dispatched every few weeks to scoop up the waste and deliver it to a recycling center.

“We must do this. And we will do this.”

If the initial operation succeeds, Slat envisions corporations and individuals sponsoring future screens. With an estimated cost of nearly $6 million per screen, a total of $360 million would be needed to sprinkle the Pacific garbage patch with 60 strainers. The price tag is forecast to pay for construction and three years of operations, with planners hoping the sale of recycled plastic will finance the project beyond that.

Silicon Valley venture capitalist Peter Thiel’s foundation found Slat online and made him a “Thiel Fellow,” which begins with a $100,000 grant to help young entrepreneurs pursue their dreams. Another tech magnate, Salesforce.com CEO Marc Benioff, tweeted his interest in the cleanup and later became one of its biggest backers.

Slat said fundraising has become easier. “I think the first round of 90,000 [Euros] was harder than the last round of 20 million,” he said. An added bonus for those who pay to install a single, elongated system: “There’s plenty of room for logos.”

‘We are not at all convinced this is going to work’

Slat is well aware that skeptics are circling his brainchild. But the greater sin, he suggests, would be not to try. “Human history,” he has said, “is a long list of things that were impossible and then that were done.”

Some scientists and environmentalists are not so sure.

George Leonard, chief scientist for the Ocean Conservancy, an environmental advocacy group, said he admires the energy and enthusiasm that the Ocean Cleanup proposal has brought to the issue of plastic pollution. “At the same time,” Leonard said, “we are not at all convinced this is going to work.”

"This has got to be resolved on land, rather than in the water."

The conservancy is focused on solutions that cut plastics off at the source, banning single-use items or blocking plastics “upstream” on rivers and other points where trash spills into the ocean at an estimated rate of 8 million metric tons a year. “This has got to be resolved on land, rather than in the water,” Leonard said, otherwise cleanup crews will face the “Sisyphean task” of removing ever-greater volumes of new plastic.

The Ocean Cleanup researchers said their aerial and shipboard studies in the Pacific have shown the majority of the plastic pollution lies near the surface, where the device can scoop it up. But the National Oceanographic and Atmospheric Administration’s Marine Debris Program emphasizes that the pollution “is not only located on the water’s surface, but throughout the water column and all the way down to the ocean floor” — out of reach of Slat’s device.

Slat’s team also faces questions about whether organisms — from plankton to whales — will be captured or disturbed by the giant scrims. The same with ships: Will they be able to steer clear of the lumbering screens? And if storms break up the giant collection booms will that “just create another giant floating marine debris?” asked Kim Martini, a physical oceanographer trained at the University of Washington.

Engineers at Ocean Cleanup headquarters in Delft think they have the answers. A ship with independent monitors will be stationed for six months beside the first installation, scheduled for September, to monitor the impact on sea life. And the screens will be outfitted with night lights, radar reflectors, electronic-identifying signals and GPS — all of which Slat’s team believes will make the systems easily detectable in an area they say is fairly light on shipping, anyway. And, as to potential mechanical collapses, the giant pipe is broken up by bulkheads, to prevent one flooded section from dragging down the whole apparatus.

Slat calls many of the concerns “outdated” — based on earlier designs that he said have been tossed aside, after “hundreds of scale model tests and prototypes.”

‘Savior of the Oceans’

Once the first full-size screen has been assembled in a couple of months, it will be ready to be eased into San Francisco Bay, towed under the Golden Gate Bridge and into the Pacific. The Ocean Cleanup crew will unleash what Slat calls an “entirely new machine” about 250 miles offshore, to check its performance. Then it will be an 800-mile voyage to the heart of the Great Pacific Garbage Patch.

Slat will not be along for the ride. “I get seasick quite badly,” he explained, “so I'll leave that to other people to go out.”

“He works on it whenever he is not sleeping."

Still, Slat is nothing if not dogged. He spends half his nights with his girlfriend and half at home with his mother, riding his bike to work. He is more likely to be found in the Ocean Cleanup’s offices in Delft, though he also travels worldwide to promote the project. He has lunched with the king and queen of Holland, hobnobbed with French President Emmanuel Macron and been interviewed for a short documentary on his quest by the actor and singer Jared Leto. Among his sea-loving countrymen, he is a symbol of visionary striving. The news magazine Elsevier Weekblad last year named him Dutchman of the Year and “Savior of the Oceans.”

“He works on it whenever he is not sleeping,” said Arjen Tjallema, the project’s technology manager. “And maybe he even dreams about it, but I don’t know that.”