science in the face of impossible ocean cleaning

In recent years, projects have multiplied, as awareness of the dangers of plastic waste in aquatic environments has grown. But while the production of this material continues to grow, actions remain minimal.

“There was a stone age, a bronze age… And today we are in the middle of the plastic age.” In 2012, the man who started his TEDx conference in Delft (Netherlands) was 18 years old, the age of dreams and nerve. An aspiring engineer, Boyan Slat then excited the world with his concept of“marine waste extraction”. “I think the North Pacific trash vortex can be cleaned up in five years,” he assures us in front of a sketch of floating barriers capable of catching surface waste carried by the current. A simple idea that appeals to the general public, already excited by the audacity and the age of the captain.

Large-scale floating dams, river dams, boats, wheels, detection aids, waste traps for waterways, drones and robots, sand filters, bubble walls, surface skimmers, vacuum cleaners… The number of promising devices to combat plastic pollution in aquatic environments has since exploded. In a report published in October 2023 (PDF)the Environmental Investigation Agency (EIA), a British NGO, lists 38, functional or under study. A multitude of more or less virtuous solutions which European Maritime Day, Monday May 20, provides the opportunity to look into.

“To attract media attention, you need something spectacular and innovative”, estimates Isabelle Poitou, marine biologist specializing in marine waste. The crazy project of Boyan Slat and his NGO, The Ocean Cleanup, “gave visibility to this problem. With this speech, delivered by someone young, it raised the hope of being able to do something about it”explains the ddirector of the MerTerre association. But at the time, it is “skeptical” in the face of the enthusiasm generated by the Dutch NGO. “Since 80% of the waste found at sea comes from land, wouldn’t all this money invested to collect plastic in the middle of the Pacific be better used on targeted actions at the source of this pollution? , she asks herself. But looking back, I say to myself: still, what they were able to extract from the ocean, it’s not bad!'”

Some 80,000 tonnes of plastic are floating in the North Pacific vortex, explains Laurent Lebreton. In 2018, with his team, the chief scientist of The Ocean Cleanup estimated the size of this “seventh continent” : almost three times France. For the moment, we have recovered around 500 tonnes of plastic waste, which represents around 0.5%. of what floats in the area, explains the oceanographer. “This is little”he admits, mais “This allowed us to test processes and collect valuable data.”

In 2024, The Ocean Cleanup, with its three waste capture devices operating in this vortex, no longer hopes to clean the North Pacific in five years. With ten of these systems operating continuously for around ten years, we can clean up more than 80% of what accumulates in the North Pacific, believes Laurent Lebreton. What we need now is to accelerate.” But, ten years after the media hype, there is hardly any trace at sea of ​​armadas eating floating waste.

Computer-generated image modeling of the hybrid boat project

The most spectacular projects are also the most expensive. THE Mantathe extraordinary factory boat from The Sea Cleaners, announced in 2016 by Franco-Swiss navigator Yvan Bourgnon, he also pays the price of this logic. The launch planned for 2022 was postponed to 2024, then to 2027…

Much fuss over nothing? “The best strategy remains to prevent waste from going into the water“, notes Isabelle Poitou. Failing to make his dream come true Manta, The Sea Cleaners is already fighting plastic waste in Indonesia, where the organization is developing sorting infrastructures. The Ocean Cleanup has also redirected part of its action towards less fanciful initiatives. Around ten more modest boats are posted in Jamaica or Guatemala, to clean up at the entrance to ports and river mouths, last stops with the open sea.

Has the solution finally been found? Without a rapid reduction in overconsumption of plastic, the quantity of waste produced worldwide could triple by 2060, underlines the OECD. “J“I fear that despite the beautiful images, we are several orders of magnitude short of the size of the problem”, comments philosopher and research director at CNRS Roberto Casati, specialist in representations linked to the ocean. A bit like using your hand vacuum cleaner to clean the Champs-Elysées after the July 14 parade.”

In its report, the EIA denounces cleaning technologies that are barely good enough “attract the public’s attention”, useless, even counterproductive. They are “a distraction”even deplores the British NGO, which insists on the urgency of reducing plastic production.

A sea of ​​plastic in the port city of Belawan, on the island of Sumatra (Indonesia), June 4, 2022. (SUTANTA ADITYA / SHUTTERSTOCK / SIPA)

In a world that is (slowly) moving towards low-carbon energies, oil and petrochemical companies have invested massively in the sector. Accused by NGOs and scientists of fighting any attempt at significant reduction, they are the all-out promotion of recycling initiatives and cleaning up the waste they produce. Tea Ocean Cleanup, which makes its living from philanthropy, has joined forces with Coca-Cola, the leading polluter in this area, according to the report by the NGO Break Free from Plastic.

As for the Pepsico group (fourth largest plastic polluter), it appears with the oil companies Exxon and Chevron or the chemist BASF among the members of theAlliance to End Plastic Waste (AEPW). In developing countries, this structure created in 2019 at the initiative of TotalEnergies ensures the fight against plastic waste, while praising the merits of this same industry. Dn a 2022 report, the NGO Planet Traker (PDF link) denounced a “sophisticated greenwashing”, while a representative of the AEPW delivered the following year to The new factory its 100% recycling strategy. A management of the “end of life” material which, for multinationals in the sector, “will itself slow down the creation of new virgin plastic production units”.

Simon Bernard, founder of Plastic Odyssey, also believes in a second life for plastic. “Pretending to be able to clean the ocean is a lie,” he says on the phone, from his laboratory boat, moored for a few days in New Caledonia. But the approach must “be accompanied by real political measures from the international community to stop the overproduction of plastic”.

Parti of Marseille in October 2022 for three years, its crew, made up of engineers and other biologists, is not intended to collect all trash. With a concept of a pocket factory that fits in a container, he explains their mission: “At each stopover, try to convince local actors, entrepreneurs, institutions, residents, etc., to set up local sectors for processing this marine plastic waste, which are economically viable.” There are endless possibilities for this plastic which can become boards for construction, furniture or, through pyrolysis, serve as fuel.

During a stopover in Dakar, Senegal, on February 22, 2023, Baptiste Lomenech (second from left), from the Plastic Odyssey project, presents the operation of the waste transformation laboratory used on board the boat, with a view to encouraging the deployment of this "low-tech" by local entrepreneurs.  (SEYLLOU / AFP)

Collect, sort, recycle… “It’s like Sisyphus pushing his rock up the mountain before starting again,” relieving Aurélien Strmsek, head ofwaste collections within the Surfrider Foundation. “Collection, not cleaning”, he insists. Inventorying waste collected on beaches and along rivers helps to “understand the sources of pollution to reduce these sources as a priority”, he explains. This approach pushed Isabelle Poitou to create the Observatory for Waste in Aquatic Environments in 2006.. It is also this objective that motivates The Ocean Cleanup or The Sea Cleaners. But at the Surfrider Foundation, “we consider that starting with cleaning“If we first stop the flow of single-use plastic, we’re looking at the problem in reverse.” REMARK Aurélien Strmsek.

For Laurent Lebreton, wanting the tap to close does not prohibit continuing to mop up. He defends useful work, which has made it possible to act on the question of fishing nets or to provide scientific arguments to States, which are currently negotiating the terms of a treaty on plastic. “It’s like a time bombestimates the scientist, The longer we wait, the more plastics degrade in the environment.”

To those who point out ineffective or even counterproductive missions, Laurent Lebreton responds : “It’s all large waste that will not become microplastics, then nanoplastics, from which we now know how difficult it is to extract.”

“Projects aimed at cleaning up marine plastic pollution still face a number of limitations,” estimates François Galgani, oceanographer at Ifremer. “Only, the locks are loosening little by little.” Waste collection and recycling, “it’s the gold rush”, he says, citing a Chinese example of collection and processing on an industrial scale.

“Until last year, no one imagined that we could have such a structured network, creating dozens of jobs,” enthuses the oceanographer. As for micro and nanoplastics, they are now the subject of abundant research. And new hopes.

For his “microplastic magnet”, the young Irishman Fionn Ferreira received the prize for “European inventors of the year” 2023, awarded by the European Patent Office. The student had already won the 2019 Google Science Fair competition, as well as $50,000 for this invention. His objective, he explained then, was to develop his start-up with a view to tackle ocean pollution on a large scale. The age of dreams and nerve still wants to believe in the end of “the age of plastic”.


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