How do we clean plastics out of our oceans?

Check out this video posted recently by The Ocean Cleanup. It shows the latest haul of their ocean-cleaning system, called "Jenny," which is hard at work removing plastics from the Great Pacific Garbage Patch. The tweet explains:

We've just improved on our single largest System 002 catch record. On October 24, we extracted 10,755 kg of plastic from the Great Pacific Garbage Patch after less than five days.

The Ocean Cleanup, which deems itself "The Largest Cleanup in History," is a non-profit organization that is trying to clean plastics out of our oceans, specifically targeting ocean garbage patches like the Great Pacific Garbage Patch, through developing and scaling technologies that operate sort of like giant trawl nets. Their website explains how their system works:

To clean an area of this size, a strategic and energy-efficient solution is required. With a relative speed difference maintained between the cleanup system and the plastic, we create artificial coastlines, where there are none, to concentrate the plastic. The system is comprised of a long U-shaped barrier that guides the plastic into a retention zone at its far end. Through active propulsion, we maintain a slow forward speed  with the system.

The circulating currents in the garbage patch move the plastic around, creating natural ever-shifting hotspots of higher concentration. With the help of computational modeling, we predict where these hotspots are and place the cleanup systems in these areas.

Not everyone is a fan of such efforts to rid our oceans of plastics, however. Earlier this year Vox wrote a story documenting the skepticism of some marine biologists, who argue that projects like The Ocean Cleanup are ineffective at best and harmful at worst. Benji Jones of Vox explains:

On its face, The Ocean Cleanup's approach to solving one of the hardest environmental problems appears to be a worthy one. But the whole squabble raises a bigger question about cleaning up plastic in the open ocean: Is it even a good idea to begin with?

Everyone can agree that plastic waste is a scourge. Between 2000 and 2019, plastic production worldwide doubled, reaching 460 million metric tons — and only a small fraction of that gets recycled. The rest is burned, buried, or ends up in the environment, including the sea. Some estimates suggest that by 2050, there could be more plastic in the oceans, by weight, than fish.

But some scientists think that cleaning up the open ocean is a futile, and perhaps even harmful, endeavor. Several marine biologists told Vox that existing methods, including The Ocean Cleanup's strategy, are inefficient and often produce pollution themselves. Plus, this approach can kill sea creatures — the very animals these efforts are ultimately trying to protect. 

Other reasons marine scientists are wary of the effectiveness of ocean cleanup projects include that the plastics are too spread out to actually be collected, and much of the plastic is in such small particles that technologies like those used by The Ocean Cleanup don't work on them. Furthermore:

Only about 1 percent of the plastic we dump into our oceans ends up in these kinds of patches (it's still somewhat of a mystery where the rest goes). So even if ocean cleanups were more efficient, they wouldn't make a significant dent in the overall waste problem.

Instead of giant trawling technologies, many marine scientists believe that better solutions include reducing how much plastic is generated to begin with, and using tools that capture and remove plastics from rivers and coastal areas before they reach the ocean—like Mr. Trash Wheel, who works to collect waste in Baltimore's Inner Harbor.