The patch is created in the gyre of the North Pacific Subtropical Convergence Zone.
The Great Pacific garbage patch (also Pacific trash vortex) is a garbage patch, a gyre of marine debris particles, in the central North Pacific Ocean. It is located roughly from 135°W to 155°W and 35°N to 42°N. The collection of plastic and floating trash originates from the Pacific Rim, including countries in Asia, North America, and South America. The gyre is divided into two areas, the "Eastern Garbage Patch" from California to Hawaii, and the "Western Garbage Patch" extending from Hawaii to Japan.
Despite the common public perception of the patch existing as giant islands of floating garbage, its low density (4 particles per cubic metre (3.1/cu yd)) prevents detection by satellite imagery, or even by casual boaters or divers in the area. This is because the patch is a widely dispersed area consisting primarily of suspended "fingernail-sized or smaller"—often microscopic—particles in the upper water column known as microplastics. Researchers from The Ocean Cleanup project claimed that the patch covers 1.6 million square kilometres (620 thousand square miles). Some of the plastic in the patch is over 50 years old, and includes items (and fragments of items) such as "plastic lighters, toothbrushes, water bottles, pens, baby bottles, cell phones, plastic bags, and nurdles." The small fibers of wood pulp found throughout the patch are "believed to originate from the thousands of tons of toilet paper flushed into the oceans daily."
Research indicates that the patch is rapidly accumulating. The patch is believed to have increased "10-fold each decade" since 1945. Estimated to be double the size of Texas, the area contains more than 3 million short tons (2.7 million metric tons) of plastic. The gyre contains approximately six pounds of plastic for every pound of plankton. A similar patch of floating plastic debris is found in the Atlantic Ocean, called the North Atlantic garbage patch. This growing patch contributes to other environmental damage to marine ecosystems and species.
The patch was described in a 1988 paper published by the National Oceanic and Atmospheric Administration (NOAA). The description was based on research by several Alaska-based researchers in 1988 who measured neustonicplastic in the North Pacific Ocean.
Researchers found relatively high concentrations of marine debris accumulating in regions governed by ocean currents. Extrapolating from findings in the Sea of Japan, the researchers hypothesized that similar conditions would occur in other parts of the Pacific where prevailing currents were favorable to the creation of relatively stable waters. They specifically indicated the North Pacific Gyre.
In 2009, two project vessels from Project Kaisei/Ocean Voyages Institute; the New Horizon and the Kaisei, embarked on a voyage to research the patch and determine the feasibility of commercial scale collection and recycling. The Scripps Institute of Oceanography's 2009 SEAPLEX expedition in part funded by Ocean Voyages Institute/Project Kaisei also researched the patch. Researchers were also looking at the impact of plastic on mesopelagic fish, such as lanternfish.
In 2010, Ocean Voyages Institute conducted a 30-day expedition in the gyre which continued the science from the 2009 expeditions and tested prototype cleanup devices.
in July/August 2012 Ocean Voyages Institute conducted a voyage from San Francisco to the Eastern limits of the North Pacific Gyre north, (ultimately ending in Richmond British Columbia) and then made a return voyage which also visited the Gyre. The focus on this expedition was surveying the extent of tsunami debris from the Japanese earthquake-tsunami.
Sources of the plastic
In 2015, a study published in the journal Science sought to discover where exactly all of this garbage is coming from. According to the researchers, the discarded plastics and other debris floats eastward out of countries in Asia from six primary sources: China, Indonesia, the Philippines, Vietnam, Sri Lanka and Thailand. In fact, the Ocean Conservancy reported that China, Indonesia, Philippines, Thailand, and Vietnam dump more plastic in the sea than all other countries combined. China alone is responsible for 30% of worldwide plastic ocean pollution (China has approximately 18% of the world's population). Efforts to slow land generated debris and consequent marine debris accumulations have been undertaken by the Coastal Conservancy, Earth Day, and World Cleanup Day.
According to National Geographic, "80 percent of plastic in the ocean is estimated to come from land-based sources, with the remaining 20 percent coming from boats and other marine sources. These percentages vary by region, however. A 2018 study found that synthetic fishing nets made up nearly half the mass of the Great Pacific Garbage Patch, largely due to ocean current dynamics and increased fishing activity in the Pacific Ocean."
In September 2019, when research revealed that much ocean plastic pollution comes from Chinese cargo ships, an Ocean Cleanup spokesperson said: "Everyone talks about saving the oceans by stopping using plastic bags, straws and single-use packaging. That's important, but when we head out on the ocean, that's not necessarily what we find."
The north Pacific Garbage Patch on a continuous ocean map
The Great Pacific garbage patch formed gradually as a result of ocean or marine pollution gathered by ocean currents. It occupies a relatively stationary region of the North Pacific Ocean bounded by the North Pacific Gyre in the horse latitudes. The gyre's rotational pattern draws in waste material from across the North Pacific, incorporating coastal waters off North America and Japan. As the material is captured in the currents, wind-driven surface currents gradually move debris toward the center, trapping it.
In a 2014 study researchers sampled 1571 locations throughout the world's oceans and determined that discarded fishing gear such as buoys, lines and nets accounted for more than 60% of the mass of plastic marine debris. According to a 2011 EPA report, "The primary source of marine debris is the improper waste disposal or management of trash and manufacturing products, including plastics (e.g., littering, illegal dumping) ... Debris is generated on land at marinas, ports, rivers, harbors, docks, and storm drains. Debris is generated at sea from fishing vessels, stationary platforms, and cargo ships." Constituents range in size from miles-long abandoned fishing nets to micro-pellets used in cosmetics and abrasive cleaners. A computer model predicts that a hypothetical piece of debris from the U.S. west coast would head for Asia, and return to the U.S. in six years; debris from the east coast of Asia would reach the U.S. in a year or less. While microplastics make up 94% of the estimated 1.8 trillion plastic pieces, they amount to only 8% of the 79,000 metric tons of plastic there, with most of the rest coming from the fishing industry.
A 2017 study concluded that of the 9.1 billion tons of plastic produced since 1950, close to 7 billion tons are no longer in use. The authors estimate that 9% was recycled, 12% was incinerated, and the remaining 5.5 billion tons are in the oceans and land.
Visualisation showing how mass accumulates in gyres.
The size of the patch is indefinite, as is the precise distribution of debris because large items are uncommon. Most debris consists of small plastic particles suspended at or just below the surface, evading detection by aircraft or satellite. Instead, the size of the patch is determined by sampling. The estimated size of the garbage patch is 1,600,000 square kilometres (620,000 sq mi) (about twice the size of Texas or three times the size of France). Such estimates, however, are conjectural given the complexities of sampling and the need to assess findings against other areas. Further, although the size of the patch is determined by a higher-than-normal degree of concentration of pelagic debris, there is no standard for determining the boundary between "normal" and "elevated" levels of pollutants to provide a firm estimate of the affected area.
Net-based surveys are less subjective than direct observations but are limited regarding the area that can be sampled (net apertures 1–2 m and ships typically have to slow down to deploy nets, requiring dedicated ship's time). The plastic debris sampled is determined by net mesh size, with similar mesh sizes required to make meaningful comparisons among studies. Floating debris typically is sampled with a neuston or manta trawl net lined with 0.33 mm mesh. Given the very high level of spatial clumping in marine litter, large numbers of net tows are required to adequately characterize the average abundance of litter at sea. Long-term changes in plastic meso-litter have been reported using surface net tows: in the North Pacific Subtropical Gyre in 1999, plastic abundance was 335,000 items/km2 and 5.1 kg/km2, roughly an order of magnitude greater than samples collected in the 1980s. Similar dramatic increases in plastic debris have been reported off Japan. However, caution is needed in interpreting such findings, because of the problems of extreme spatial heterogeneity, and the need to compare samples from equivalent water masses, which is to say that, if an examination of the same parcel of water a week apart is conducted, an order of magnitude change in plastic concentration could be observed.
— Ryan et al
Pacific Ocean currents have created three "islands" of debris.
In August 2009, the Scripps Institution of Oceanography/Project Kaisei SEAPLEX survey mission of the Gyre found that plastic debris was present in 100 consecutive samples taken at varying depths and net sizes along a path of 1,700 miles (2,700 km) through the patch. The survey found that, although the patch contains large pieces, it is on the whole made up of smaller items that increase in concentration toward the gyre's centre, and these 'confetti-like' pieces that are visible just beneath the surface suggests the affected area may be much smaller. 2009 data collected from Pacific albatross populations suggest the presence of two distinct debris zones.
In March 2018, The Ocean Cleanup published a paper summarizing their findings from the Mega- (2015) and Aerial Expedition (2016). In 2015, the organization crossed the Great Pacific garbage patch with 30 vessels, to make observations and take samples with 652 survey nets. They collected a total of 1.2 million pieces, which they counted and categorized into their respective size classes. In order to also account for the larger, but more rare debris, they also overflew the patch in 2016 with a C-130 Hercules aircraft, equipped with LiDAR sensors. The findings from the two expeditions, found that the patch covers 1.6 million square kilometers with a concentration of 10–100 kilograms per square kilometer. They estimate an 80,000 metric tons in the patch, with 1.8 trillion plastic pieces, out of which 92% of the mass is to be found in objects larger than 0.5 centimeters.
While "Great Pacific Garbage Patch" is a term often used by the media, it does not paint an accurate picture of the marine debris problem in the North Pacific Ocean. The name "Pacific Garbage Patch" has led many to believe that this area is a large and continuous patch of easily visible marine debris items such as bottles and other litter – akin to a literal island of trash that should be visible with satellite or aerial photographs. This is not the case.
In a 2001 study, researchers found concentrations of plastic particles at 334,721 pieces per km2 with a mean mass of 5.1 kg (11.3 lbs) per km2, in the neuston. The overall concentration of plastics was seven times greater than the concentration of zooplankton in many of the sampled areas. Samples collected deeper in the water column found much lower concentrations of plastic particles (primarily monofilament fishing line pieces).
In 2009 Ocean Voyages Institute removed over 5 tons of plastic during the initial Project Kaisei cleanup initiative while testing a variety of cleanup prototype devices.
The 2012 Algalita/5 Gyres Asia Pacific Expedition began in the Marshall Islands on 1 May, investigated the patch, collecting samples for the 5 Gyres Institute, Algalita Marine Research Foundation, and several other institutions, including NOAA, Scripps, IPRC and Woods Hole Oceanographic Institute. In 2012, the Sea Education Association (SEA) conducted research expeditions in the gyre. One hundred and eighteen net tows were conducted and nearly 70,000 pieces of plastic were counted.
In 2012, researchers Goldstein, Rosenberg and Cheng found that microplastic concentrations in the gyre had increased by two orders of magnitude in the prior four decades.
On 9 September 2018, the first collection system was deployed to the gyre to begin the collection task. This initial trial run of the Ocean Cleanup Project started towing its "Ocean Cleanup System 001" from San Francisco to a trial site some 240 nautical miles (260 miles) away. The initial trial of the "Ocean Cleanup System 001" ran for four months and provided the research team with valuable information relevant to the designing of the "System 001/B".
In 2019 over a 25 day expedition, Ocean Voyages Institute set the record for largest cleanup in the "Garbage Patch" removing over 40 tons (80,000 pounds) of plastic from the ocean.
In 2020 over the course of 2 expeditions, Ocean Voyages Institute again set the record for largest cleanup in the "Garbage Patch" removing over 170 tons (340,000 pounds) of plastic from the ocean. The first 45 day expedition removed 103 tons of plastic  and the second expedition removed over 67 tons of plastic from the Garbage Patch.
In 2021, The Ocean Cleanup collected 63,182 pounds (28,658 kg) of plastic using their "System 002". The mission started in July 2021 and concluded on October 14, 2021.
Discovery of a thriving ecosystem of life at the Great Pacific garbage patch in 2022 suggested that cleaning up garbage here may adversely remove this plastisphere.
In July of 2022, The Ocean Cleanup announced that they had reached a milestone of removing the first 100,000 kg of plastic from the Great Pacific Garbage Patch using "System 002" and announced their transition to "System 03", which is claimed to be 10 times as effective as its predecessor.
^See the relevant sections below for specific references concerning the discovery and history of the patch. A general overview is provided in Dautel, Susan L. "Transoceanic Trash: International and United States Strategies for the Great Pacific Garbage Patch", 3 Golden Gate U. Envtl. L.J. 181 (2007).
^"After entering the ocean, however, neuston plastic is redistributed by currents and winds. For example, plastic entering the ocean in Korea is moved eastward by the Subarctic Current (in Subarctic Water) and the Kuroshio (in Transitional Water, Kawai 1972; Favorite et al. 1976; Nagata et al. 1986). In this way, the plastic is transported from high-density areas to low-density areas. In addition to this eastward movement, Ekman stress from winds tends to move surface waters from the subarctic and the subtropics toward the Transitional Water mass as a whole (see Roden 1970: fig. 5). Because of the convergent nature of this Ekman flow, densities tend to be high in Transitional Water. Also, the generally convergent nature of water in the North Pacific Central Gyre (Masuzawa 1972) should result in high densities there also." (Day, et al. 1988, p. 261) (Emphasis added)
^Will Dunham (12 February 2019). "World's Oceans Clogged by Millions of Tons of Plastic Trash". Scientific American. Archived from the original on 16 November 2019. Retrieved 31 July 2019. China was responsible for the most ocean plastic pollution per year with an estimated 2.4 million tons, about 30 percent of the global total, followed by Indonesia, the Philippines, Vietnam, Sri Lanka, Thailand, Egypt, Malaysia, Nigeria and Bangladesh.
^For this and what follows, see Karl, David M. (May–June 1999). "A Sea of Change: Biogeochemical Variability in the North Pacific Subtropical Gyre". Ecosystems. 2 (3): 181–214. doi:10.1007/s100219900068. S2CID46309501. For gyres generally, see Sverdrup HU, Johnson MW, Fleming RH (1946). The oceans, their physics, chemistry, and general biology. New York: Prentice-Hall.
^Ferris, David (May–June 2009). "Message in a bottle". Sierra. San Francisco: Sierra Club. Archived from the original on 2 September 2019. Retrieved 13 August 2009.
^Faris, J.; Hart, K. (1994). "Seas of Debris: A Summary of the Third International Conference on Marine Debris". N.C. Sea Grant College Program and NOAA. ((cite journal)): Cite journal requires |journal= (help)
^Moore, C.J; Moore, S.L; Leecaster, M.K; Weisberg, S.B (2001). "A Comparison of Plastic and Plankton in the North Pacific Central Gyre". Marine Pollution Bulletin. 42 (12): 1297–300. doi:10.1016/S0025-326X(01)00114-X. PMID11827116.
^Emelia DeForce (9 November 2012). "The Final Science Report". Plastics at SEA North Pacific Expedition. Sea Education Association. Archived from the original on 2 March 2020. Retrieved 11 September 2019.
Oliver J. Dameron; Michael Parke; Mark A. Albins; Russell Brainard (April 2007). "Marine debris accumulation in the Northwestern Hawaiian Islands: An examination of rates and processes". Marine Pollution Bulletin. 54 (4): 423–33. doi:10.1016/j.marpolbul.2006.11.019. PMID17217968.
Gregory, M.R.; Ryan, P.G. (1997). "Pelagic plastics and other seaborne persistent synthetic debris: a review of Southern Hemisphere perspectives". In Coe, J.M.; Rogers, D.B. (eds.). Marine Debris: Sources, Impacts, Solutions. New York: Springer-Verlag. pp. 49–66.