Guest Essay by Kip Hansen – 10 September 2022
A couple of new studies have come out that challenge the Jenna Jambeck widely accepted consensus view on Pelagic (Oceanic) Plastic. Jambeck has for many years produced study after study blaming the escaped plastic found in the world’s oceans on the discharge of plastics via the rivers of the world which then lead to the ill-named and mostly-nonexistent ocean gyre plastic-filled Garbage Patches.
[ Readers can background this essay by reading my several essays on this topic which have appeared here at WUWT ]
There have been two far less hysterical studies on floating plastics in the world’s oceans. The first one is a couple of years old now. The research was carried out by a group of South African and Canadian scientists. They studied floating plastic debris that washed ashore on a small island, Inaccessible Island, an uninhabited island in the Tristan da Cunha archipelago in the central South Atlantic Ocean:
The island is so tiny that it does not even show at that scale, nor does the group of islands it belongs to. The Wiki article has a photograph of the little beach researched by the study, on which they counted debris washed ashore and identified it by country of origin, and when possible, by manufacture date. The results:
Significance: Many oceanic islands suffer high levels of stranded debris, particularly those near subtropical gyres where floating debris accumulates. During the last 3 decades, plastic drink bottles have shown the fastest growth rate of all debris types on remote Inaccessible Island. During the 1980s, most bottles drifted to the island from South America, carried 3,000 km by the west wind drift. Currently, 75% of bottles are from Asia, with most from China. The recent manufacture dates indicate that few bottles could have drifted from Asia, and presumably are dumped from ships, in contravention of International Convention for the Prevention of Pollution from Ships regulations. Our results question the widely held assumption that most plastic debris at sea comes from land-based sources.
[Note: To drift from China, the bottles would have had to fight their way against prevailing currents around SE Asia, across the Indian Ocean, and around South Africa. — kh]
Note that there are a number of islands that serendipitously act as collection points for wind and current driven floating objects. Inaccessible Island is one, and in the Caribbean, Big Sand Key is another with its eastern-facing shore being famous among Caribbean cruisers for its beach combing opportunities. [ Our best finds were two 8-inch diameter antique metal fishing net floats all the way from Portugal and a small plastic brontosaurus. ]
The second and most recent paper is: “Industrialised fishing nations largely contribute to floating plastic pollution in the North Pacific subtropical gyre” by Lebreton et al. Lebreton is with The Ocean Cleanup, the NGO involved with an effort to rid the oceans of plastic.
The Ocean Cleanup website says; “Our new study published today in Scientific Reports reveals 75% to 86% of plastic debris in the Great Pacific Garbage Patch (GPGP) originates from fishing activities at sea.”
This study also found that a great deal of the rest of the debris in the North Pacific Gyre seems to have originated from the tsunami resulting from the 2011 Tohoku earthquake which also caused the Fukushima Daiichi nuclear disaster. That tsunami is believed to have washed as much as 5 million tonnes of waste into the sea, primarily plastics and styrofoam.
Their new study contradicts their long-standing belief that plastics found floating in the oceans comes from escaped plastic trash washing down rivers, though they still also stick to the claim: “Plastic emissions from rivers remain the main source of plastic pollution from a global ocean perspective.” The newest overall view is that riverine plastics end up back on the shores of the region of their origin or, if of higher density, sink in the local coastal area.
The study is well worth a read for those interested in the plastic pollution issue.
However, the evidence for the origins of pelagic plastic — plastic floating on the surface of the oceans — is shifting from “emissions from rivers” to a source far more likely – “originates from fishing activities at sea”. It is not only that the vast majority of the mass-by-weight of plastic debris found is as tangled masses of lost or abandoned fishing nets and ropes obviously is from fishing vessels, but the South Atlantic study finds that the other trash, floating drink bottles and other plastic containers also originate on ships and boats – either discarded intentionally as trash or thrown of washed overboard.
In my years in the merchant marine (Panamanian seaman’s papers, as a junior ship’s officer) in the 1970s, ship’s trash was stuffed into empty gunnysacks, weighted when possible with discarded ship’s engine and plumbing parts, and thrown overboard when we were on the open sea. Garbage from the galley and dining rooms, on the other hand, was simply dumped over the taffrail anywhere when out of sight of land, much to the delight of the sea birds, which would feast on the garbage itself or on the fish attracted by the food. Glass bottles and jars were often saved to be thrown overboard off the bow when we were underway and used by officers lined up along the prom deck railing for target practice with various firearms as the items floated by.
Since the late-1970s, all ships are required to post signage clearly laying out the requirements for disposal of trash and garbage at sea under international MARPOL treaties. Captains and owners are required to enforce these rules and can be held personally responsible for violations of them by their ship’s crew. Since 1988, MARPOL Annex V completely bans the dumping plastic into the ocean.
1. Human trash, and especially all types of plastics, should be properly contained, collected and disposed of in a responsible manner and not allowed to escape into the greater natural environment, including our rivers, lakes and oceans. Plastics should be recycled when possible. It is my opinion that non-recyclable plastics should be used as fuel in waste-to-energy plants, a concept with which some people disagree.
2. Plastics are possibly the most important, or at least the most useful, invention of materials science of the modern era, allowing the manufacture of “nearly everything”. Thus, while disposal of products made from plastics can be problematic, the present-day demonization of plastics is entirely wrongheaded.
4. The vast majority of pelagic plastic — plastic items floating at sea —comes from the fishing fleets of the world. This new emerging understanding simplifies the problem and allows development of new solutions. Even plastics washed ashore on remote islands apparently originates on fishing vessels.
5. The huge impact of the ubiquitous disposable PET drinking water bottle could be alleviated by a minor reworking the composition of the PET bottles so that they more rapidly breakdown under UV radiation (sunlight) or, even better, to be more easily broken down through consumption by already ubiquitous soil- or water-based bacteria. Most floating plastics in the sea are already being consumed by micro-organisms and once they have broken down into very small pieces, are entirely consumed.
6. Nature makes use of every possible resource. Those ugly masses of tangled floating fishing nets and lines become floating reefs supporting creatures and fishes of all sorts. It is only humans that think they are bad.
But before the lost and abandoned nets become tangled by the motion of the seas they can kill fish and marine mammals. Fishing fleets should be required to place now-inexpensive tracking devices on deployed nets and be held responsible for any failure to retrieve lost nets.
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I have written on this issue many times, but the crazies keep re-creating the false narrative that plastics themselves are bad and that all production of plastics should be stopped. That idea is misanthropic and anti-advancement.
Our societies do need to do a better job of dealing with our waste and trash. The developed nations should be tackling this problem internally and supplying foreign aid to nations still struggling with even the basic concepts of waste collection and proper land-filling. With land-filling being problematic for many nations that still need dependable electric supplies, new cleaner waste-to-energy plants might be a solution to both problems.
The Inaccessible Island study seems to implicate Asian nation’s fishing fleets for much of the floating debris at sea. Perhaps the Greenpeace-types and SeaKeepers could be effective in this regard.
If you live on or near the sea, you can do your part encouraging fellow boaters to be more careful with plastics onboard and volunteering to participate in riverside and beach cleanups.
Thanks for reading.
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via Watts Up With That?
September 11, 2022 at 01:03AM