Gallery: The Fallacy of Cleaning the Gyres of Plastic With a Floating “...


As the policy director of the ocean conservation nonprofit, I can tell you that the problem of ocean plastic pollution is massive. In case you didn’t know, an ocean gyre is a rotating current that circulates within one of the world’s oceans – and recent research has found that these massive systems are filled with plastic waste. There are no great estimates (at least scientific) on how much plastic is in the ocean, but I can say from firsthand knowledge (after sailing to four of the world’s five gyres) that it’s so pervasive it confounds the senses. Gyre cleanup has often been floated as a solution in the past, and recently Boyan Slat’s proposed ‘Ocean Cleanup Array’ went viral in a big way. The nineteen-year-old claims that the system can clean a gyre in 5 years with ‘unprecedented efficiency’ and then recycle the trash collected. The problem is that the barriers to gyre cleanup are so massive that the vast majority of the scientific and advocacy community believe it’s a fool’s errand – the ocean is big, the plastic harvested is near worthless, and sea life would be harmed. The solutions starts on land.

Editor’s Note: This piece was written in response to a story published in 2013. As of 2014, Boyan Slat has conducted a feasibility study for the Ocean Cleanup Array and published a 530-page report that addresses criticismcheck it out here.

If an outlier subset of the movement to end oceanic plastic pollution exists, it would be the proponents of gyre cleanup. These guys pop up now and again (make no mistake, Slat’s idea and drawings are not new), but for some reason his idea got big media attention. No serious scientist or policy advocate believes that microplastic gyre cleanup is a real strategy for ridding micro-plastics from the oceans—not even The National Oceanic and Atmospheric Administration (NOAA). Industry often backs ‘gyre cleanup’ concepts because they give the impression that we can continue to consume more and more and good old human ingenuity will figure out how to solve all the environmental problems. The public, for their part, loves the thought of a quick fix and wants to believe that a ‘boy genius’ can come along and solve a problem that all the old crusty PHDs can’t.

It’s a great story, but it’s just a story. I find debating with gyre cleanup advocates akin to trying to reason with someone who will argue with a signpost and take the wrong way home. Gyre cleanup is a false prophet hailing from La-La land that won’t work – and it’s dangerous and counter productive to a movement trying in earnest stop the flow of plastic into the oceans. Gyre cleanup plays into the hand of industry, but worse, it diverts attention and resources from viable, but unsexy, multi-pronged and critically vetted solutions.

Slat’s project as it stands is in the fairy tale phase, which is where all the other gyre cleanup schemes out there are, too. So far Slat’s is not a ‘design schematic’ nor is it ‘engineered’ nor is there a business plan attached to it—a fact that Slat all of the sudden underscores in an update to the website, saying he’s just conducting a ‘feasibility study,’ and that his intention was never to suggest that it was presently viable. But that certainly is not what his website suggested before the media attention—and this is precisely why it got so much media attention. From the website: “Extract 7,250,000,000KG of plastic from the oceans in just 5 years per gyre, Contribute Now!”

Well, if Slat’s intention is to funnel the money into a feasibility study, maybe I can save him some money. Let’s look at gyre cleanup schemes from a vantage governed not by dreams, passion and media preciousness, but from something a little more effective and a lot more boring—reason.

The sea is cruel and it’s really really really big

The nonprofit I work for, as part of its mission, takes people other than scientists on expeditions to the gyres. Why? It’s simple; we want regular people, like Slat, to understand the scale of the problem and the vectors that contribute to the difficulty of solving it by being informed by a firsthand vantage. So far, we’ve taken one gyre cleanup advocate across the South Atlantic, from Brazil to South Africa. We had 22 days of storms with seas in excess of 30 feet at times. By the time we got to the other side, some 30+ days later, he’d abandoned his hope of cleaning the gyres once he realized how big a ‘place’ we’re talking about. What I find astonishing is that out of all the gyre cleanup proponents I’ve met, none of them have ever been to the gyres.

The ocean surface is 315 million square kilometers; 70% of the earth’s surface. Plastic isn’t just contained within the borders of the gyres, it’s everywhere in the ocean. Half of it, like Coke bottles and PVC pipe, sinks. What does a garbage patch look like? Imagine the night sky on a cloudless, moonless night. Now replace the ocean surface with space, and the stars with plastic; it’s dispersed and it goes on infinitely. Yes, humans have managed to create a problem on a degree of scale that’s nearly incomprehensible and so overwhelming we’re predisposed to like ideas like Slat’s because it has the appearance of near divine simplicity. Every time a gyre cleanup proponent has shown me a design for addressing the problem, the first thing I ask is, ‘do you have the money to make 20 million of those doo-hickies?’ They look at me with a puzzled look, and I just mutter, ‘The ocean is really, really, really, big.”

But beyond the size of the ocean, the sea is one giant corrosive force. Even on just a month-long sail across The South Atlantic, we tore our sails twice, broke some rigging, and utterly destroyed a wind-powered generator—all due to the force of nature. Any blue water sailor will tell you about how destructive the sea is to anything with moving parts. That’s why sailors say, ‘a boat is a hole you fill with money.’ Heck, outer space is less corrosive to machines than the ocean is.

But let’s look at a practical example. My home state of Oregon has been trying to create North America’s first offshore wave energy farm. The first test buoy that was launched, just about 2.5 miles offshore, sank after just a few months. That buoy had a ‘100 year survivability’ rating, and wasn’t just an idea on an Ipad. That was the result of an incredible amount of engineering and venture capital. The company, Finavera Renewables, has since abandoned their wave energy ambitions. Is it because Finavera lacked vision? No. Whether you like it or not, Finavera, like all for-profit schemes, is governed by profit and loss. What’s interesting is that Finavera actually had a product (energy) that was worth money, and still it didn’t pencil out. Eventually, because energy IS so valuable and wave farms are near shore, the technology will become more viable. Which leads me to my next point.

The economics of gyre cleanup don’t work – and a few notes on recycling

The two most common types of plastic in the ocean are polyethylene (PE- plastic bags, dispensing bottles) and polypropylene (PP- bottle caps, fishing gear). So, it stands to reason that these types of plastic would be what Slat’s machine would ‘harvest’ to sell to recyclers. Well, if the economic viability of Slat’s ocean cleaning device rests on his assumption that it will produce a product that will be sold in the market, he needs to better understand the market landscape for his product.

Plastics, chemically speaking, are polymer chains of monomer hydrocarbon molecules. Ultraviolet light weakens the polymer chains until they break, which is why you have the confetti-like micro-plastics found in the ocean. The number one barrier to a closed loop, cradle-to-cradle scenario for plastic is that recycling weakens the polymer chains and thus, the structural integrity of what you can recycle them into. Ocean-borne plastics are so brittle you can break them apart with your fingers, and they’re also saturated with toxic chemicals present in seawater. Another issue is bio-fouling. Life adheres to plastic, and for the most part, plastic can only be recycled if it’s clean or cleaned. Another issue is that plastics have to be separated by type, i.e. PP, PE, etc. In an ocean plastic scenario where all these bits are crazy small, this requires spectroscopic analysis that identifies plastic by the frequency of light it reflects. This is very expensive, even in an automated scenario. Another issue is transportation—plastic bags are hardly ever recycled because in most places, it’s more expensive to transport them to a recycler then the recycler will pay for them. So, from the market analysis standpoint in a gyre cleanup business plan, ocean plastics are about the worst possible feedstock for recycling imaginable, putting the product at a severe competitive disadvantage. Put it this way: Hiring people to climb trees in New York City to gather all the plastic bags in their branches would be more efficient and cheaper than ocean harvesting. Wait, do I sound crazy? Or visionary?

One company, Envision Plastics, has successfully managed to use ocean plastics, working with a company called Method to create a bottle with 25% post-ocean High Density Polyethylene (HDPE). But the economic viability of the product is the issue. Out of 67 products listed on Method’s website, only one is packaged in this type of bottle and it costs a dollar more than other products of the same volume in other types of recycled bottles. Envision Plastics does not advertise ‘Ocean Plastic’ as a wholesale product available on their website. The fact that Method’s ‘Ocean Plastic’ didn’t take off should be noted in Boyan Slat’s feasibility study. Slat seems at least cognizant of this problem when he says:

“According to current estimations – due to the plan’s unprecedented efficiency—recycling benefits would significantly outweigh the costs of executing the project. Although the quality of the plastic is somewhat lower than ordinary recycled plastic it could for example be mixed with other plastics to produce high-quality products. PR through an Ocean Plastics brand can further increase the plastics’ value, and would create awareness with the consumer.”

First up, there is no “plan” so it’s really difficult to vet its “unprecedented efficiency.” And “quality of plastic somewhat lower?” The word “terrible” is a better description. Though cool and innovative, Envision’s Ocean Plastic hasn’t taken off – and do you remember the massive PR around it just months ago? It’s gone.

Like the size of the ocean, the amount of plastic we consume is an issue of scale. In North America, the annual per capita consumption of plastic is roughly 326 pounds as of 2010. That statistic is up nearly a 100 pounds per capita from 2001. Of course, the plastics industry doesn’t like the idea of us consuming less because it means less plastic sold. They keep saying all we need is ‘more recycling.’ But despite even nominal gains in recycling, the sum total of virgin plastics produced in the world annually is going up, not down, which means the sum total of plastics entering the ocean is going up, too. I’m not anti-recycling; recovery is part of the solution, albeit small.

The problem is that the economics of most recycling are terrible, especially in the case of Polyethylene and Polypropylene. A growing single-use input for a market that has a sustained-use durable goods output means the input is always going to be greater than the output – that is – the supply will always exceed demand. Most plastics are very difficult to recycle not because we lack infrastructure, but because they’re not worth enough in a commodities market to incentivize venture capitalists to invest in more infrastructure to process them. Let’s remember that recycling isn’t the work of little green altruistic elves and fairies, it’s a business.

But even when plastics do get recycled, in the vast majority of cases, recycling only kicks the can down the road one generation by creating a product that can’t or won’t (because of economic constraints) be recycled again. In short, the vast majority of the recycling industry isn’t doing anything to solve marine plastic pollution, and for the most part, recycling is just creating a secondary market for waste. Even if the economics of Slat’s Ocean Cleanup Array didn’t further impede its viability, more plastic would still be entering the ocean than his device would pull out. Placing fees on producers of virgin plastics, and giving breaks to those who use 100% recycled content or are actively working towards it, would help to balance this equation out and would be great news for the ocean.

What about the science?

In the simplest of terms, anything floating in the ocean tends to be a ‘party barge’ for life. What I’d like to see for Slat’s design is a time-lapse of his structure at sea predicting how fast it would be colonized by sea life—colonization happens very quickly. I can personally attest to this from recovering tsunami debris at sea, just a year after the devastating wave hit Japan. Anywhere you have seawater you’re going to have havoc wreaking barnacles. Anywhere where you have a platform, you’re going to have dead squid and flying fish stranding themselves, which will attract sea birds, and thus, guano. All of this stuff, coupled with salt, makes moving parts seize.

Little sea life attracts big sea life. Big sea life means entanglement issues. And unfortunately, sea life big or small is notorious for not doing what designers assume it will do. Slat’s design depicts massive booms sticking out of the sides in a ‘V’ pattern thus corralling the floating plastic into some mysterious filter that will separate plankton and plastic. First up, life would colonize the booms, weight it down, and create their own current and eddies around it which would affect the ‘flow’ of how the thing is supposed to work. Fish, attracted by the littler life and the protection from larger predators tend to be voracious ‘munchers’ and thus, really destructive. Oh and storms? You can’t imagine the ferocity we’re talking about until you’ve sailed in full gale. The wind itself becomes audible.

Slat claims that 24 of his devices are all that is needed to cleanup each gyre in 5 years. How massively long are the booms, and how do they stay in a ‘V’ shape that Slat assumes is needed to gather the plastic? Where on earth does the 24 number come from? Slat mentions that these would be anchored to the seabed. That’s great, but it’s not currently possible to anchor anything in 4,000 meters of water (the average depth of the open ocean). The deepest known mooring is 2,000 meters. Even if you could anchor it, one big storm and his device is going to be ripped from its mooring. Ask NOAA about how many data buoys they lose to storms, even in shallow water.

Another technicality is bycatch. Slat suggests that plankton wouldn’t be collected along with the plastic, though he admits more research is needed on this. The definition of plankton is an organism that can’t swim against a current; plankton have no control where they go and the assumption that they’ll somehow avoid the current that is taking the plastic into the processing thinga-ma-jiggy is a bad one. After conducting 50+ surface samples myself, at least half of the material we get from the surface is biomass. Zooplankton is really fragile, and trying to separate it from plastic in most cases is going to damage these critters beyond survivability, especially on an industrial scale. Plan B in Slat’s concept is to centrifuge the critters out—that would rip off their antennae and feeding apparatus. Scientists, when collecting zooplankton, use live catch nets and are very, very careful so as not to damage them. Plankton biologists, needless to say, are skeptical. Though zooplankton certainly isn’t the most charismatic fauna out there (and probably wouldn’t draw the ire of PETA if Slat’s device killed them), let’s remember that all life in the ocean depends on plankton at the base of the food chain. And if one endangered sea turtle was caught up? The fines that Slat would face would bankrupt his project in a second.

Perhaps one of the worst assumptions evident in this design is that the plastic will be on the sea surface. Researchers have shown that plastic suspends in the water column at 100-150 meters due to wave action and sea state. Not only does this mean that Slat’s design wouldn’t capture this plastic, it shows that his estimates of how much plastic is out there aren’t correct and thus, his five year timeframe to clean a gyre becomes even more unrealistic. For more analysis on what the premiere scientists working on the issue think, go here.

Why so bitter?

I absolutely love human creativity, especially when it’s channeled for a greater environmental good. But why I have such an adverse reaction to Slat’s concept is the naiveté with which he proposes it. And sure, maybe I’m a bit jealous that this tale of how solve the problem went viral when so many of my colleagues working on real solutions go unnoticed and uncelebrated by the media. But I also smell an arrogance here—an arrogance that flies in the face of everything we know about the ocean and the problems with recycling. If Slat were just simply floating a design concept, that would be one thing, but that’s not exactly how he portrays it–and all the ipso facto disclaimers working in concert with a fundraising scheme are really troubling. Slat’s facebook page feeds this in its tagline: “The first realistic ocean clean-up concept?” Seriously? Maybe he has the best intentions, but I find this gyre cleanup stuff to be a major distraction from the real solutions to the problem and as such, counter productive. To me, quite frankly, he’s selling snake oil even if he doesn’t know it yet. Remember what William Blake said about good intentions?

The good news

Here’s something that will blow your mind—to clean the ocean of floating plastic, you don’t need to go out and get it, it will come to you. Yep, that’s right. Oceanographer Curtis Ebbsmeyer, author of, Flotsametrics describes a rarely talked about phenomena that occurs naturally in the ocean called Gyre Memory. Gyre Memory demonstrates that upon each orbit of a gyre, the gyre will spit out about half its contents. These contents will then either enter another current or gyre or wash up on land. As this repeats, it means that eventually, all the plastic in the ocean will be spit – out which is why you find plastic fragments on every beach in the world. Beach cleanup is gyre cleanup.

The solution to this problem isn’t elegant, and there exists no silver bullet. The first step in solving the problem is to personally lower your plastic consumption. The next steps are to get involved in cleanups, get involved in campaigns to eliminate problem products, and demand that companies take responsibility for their products post consumer. There is a lot to be hopeful about, even if the real solutions don’t appear real sexy. But with engagement, en masse, there is light at the end of the sewer pipe. Unfortunately with Slat’s idea, I see only wasted resources and more ocean garbage in the making.

This article was written and submitted to Inhabitat by Stiv J. Wilson, Policy Director, The 5 Gyres Institute


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  1. dhyanmok July 7, 2014 at 7:03 am

    the single most telling error in Slat’s innocent (ignorant?) thinking is that if it were actually economically feasible to recycle these plastics on land, they would almost never get to the ocean in the first place. tiny case-in-point – as soon as bottle deposits were made on bottles when i was a kid, the landscape suddenly became clear of tossed litter bottles – and gave us kids pocket money— the problem here is of course – the sheer volume of plastics produced and their uneconomic recycling profile.

  2. Louise Mercier July 5, 2014 at 11:55 am

    Straw8cat: You missed the point of the article regarding the FORCE of the ocean itself. Having been a sailor – unless you have actually been out on the “Big wa-wa” (ocean) – you can’t possibly imagine how massive and powerful it is. And what about marine life, as noted in the article…these are valid points also that need to be considered. I will concur with the valid scientists that have been studying this problem for some time…they know whereof they speak. I thought Slat’s idea was brilliant – but had not thought it through, encompassing all the legitimate points in this article and I concur with its author. It MUST start on LAND and with plastic production/consumption reduction. Going directly to the source of the problem would be a more viable start.

  3. straw8cat July 5, 2014 at 10:28 am

    Boylan Slat has inspired a lot of people who are actively supporting him. Many are engineers and marine scientists, and only a few are on the payroll- what little there is of it- but the fundraising drive is going well, and just below the halfway mark to their $2 Million goal with 70 days left in the drive.

    This is the estimated cost of their first deep ocean cleanup experiment, which I believe will happen this summer.

    As for sorting out the plastics for recycling: no need to. Use a tuned microwave refinery to turn the plastics into a usable diesel fuel substitute. One machine already available on the market turns 1 kg of plastics into about 0.8litres (or was that 0.8kgs…?) of fuel or certain chemical feedstocks. I estimate the cost of that 1 litre of diesel substitute will cost about 45 cent to produce, but that might be a bit of an underestimate- it depends on the local or on-board price of electricity. Nonetheless, it should provide a profit for the operation, and eliminate the need to buy fuel if they have companion ships that can process the plastic.

    They won’t clean up everything, since the net openings will be of a certain size, and smaller bits will mostly pass through, but a lot of what is in the top meter of seawater will get scooped up. Most of the plastic turns out to be in the top 1 meter of water.

    So far, it looks like a viable project. And the project is funded by voluntary contributions, just as the experimental Solar Roadways thing is.

    Later on we will know more. Keep our fingers crossed, if you think that will help.

    You can help by donating here:Let’s see how much 5Gyres chips in.

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