The Dutch nonprofit Ocean Cleanup deployed a 609.60m-long, $US20 million unmanned boom designed to gather some of the Pacific Ocean’s massive amounts of plastic garbage from San Francisco Bay on Saturday. But it’s not clear the plan will work, the New York Times wrote.
According to the Times, the buoyant structure is currently being hauled out to a site where it will undergo testing—and if it passes, it will be brought to the Great Pacific Garbage Patch to begin the task of trapping some of the estimated 1.8 trillion pieces (80,000 tons by weight) of plastic garbage out there. Promotional materials show the structure is comprised of a long floater with a plastic skirt underneath, intended to move along with the current but at a slightly faster pace due to pressure from wind and waves. If it works as designed, it should form a U-shape that collects plastic as it drifts around and would be periodically cleaned by support vessels.
Ocean Cleanup says a fleet of dozens of identical booms could clear the garbage patch in as little as half a decade, and it could help fund itself by recycling the accumulated plastic. It also says future booms could be much cheaper, at $US5.8 ($8) million apiece.
If it works—great! However, the concept has only been tested with scale models and computer simulations. The Times wrote that environmental experts are wary that the booms might fail to catch much plastic, but simultaneously scoop up wildlife:
“There’s worry that you can’t remove the plastic without removing marine life at the same time,” said George Leonard, chief scientist at the Ocean Conservancy. “We know from the fishing industry if you put any sort of structure in the open ocean, it acts as a fish-aggregating device.”
... It is unclear how well the boom would fare on the open ocean, where it faces high winds, corrosive salt water and other environmental challenges. And then there’s the question of whether it is possible to clean half of the garbage patch in just five years.
“I think the big challenge here is not the long-term goal but the short-term goal,” Mr. Leonard said on Saturday. “Can it remove plastic at all?”
One purported issue with the design, per Business Insider, is that much of the plastic that is deposited into the ocean has already broken down and sunk much deeper than the 3.05m plastic skirt is capable of reaching. Another is that if marine life begins to accumulate on the surface (“biofouling”), it could be weighed down and plastic will just float over it. In addition to the risk of wildlife entanglement, there’s a “medium risk” acknowledged in an environmental assessment performed by Ocean Cleanup that sea turtles would be attracted to the boom and begin eating the collected plastic.
According to Wired, Ocean Cleanup said that they have designed the boom to have no risk of entanglement, though there is concern objects like rogue fishing nets could become ensnared on the structure and trap wildlife. Wired added that some experts wonder if it is a pollution risk in and of itself:
“I sort of wonder what kinds of microplastics this thing is going to be generating on its own, assuming that it’s even functioning exactly as designed,” says oceanographer Kara Lavender Law of the Sea Education Association. Worse yet, the thing could snap in a storm. “If it’s shedding nano-size particles and then gets smashed into 200-meter-long pieces, you’re really covering the whole size range there.”
Oceanographer Kim Martini, who worked on an external review of the project years ago, wrote in a blog post flagged by Business Insider that a better solution may be to deploy the booms near sources of plastic pollution, where they could trap garbage before it becomes an issue.
21-year-old Ocean Cleanup founder Boyan Slat told Sky News he agreed that the concept has not yet been proven to work, but “If we don’t clean it up now, all of it will become micro plastics and then we are in a much worse state than we are today. This is the best way we could figure out how to do it. If there are better ways, we’d love to know.”
California Coastal Commission marine debris program manager Eben Schwartz told shark researcher David Shiffman of Southern Fried Science that “To make the claim, as The Ocean Cleanup Project is, that they will ‘clean the oceans’ by 2040 or whenever is disingenuous and misleading, when it will, at best, clean a very small percentage of what’s found on the surface.”