The Great Pacific Garbage Patch, an enormous area of floating garbage halfway between California and Hawaii, is already recognized as the largest accumulation zone of ocean plastic on Earth. Now, it turns out that researchers may have been vastly underestimating its scale.
The results of a three year mapping effort by international scientists, published Thursday in the journal Scientific Reports, reveals that the amount of plastic this garbage patch contains is up to 16 times greater than initially thought.
According to the study, the patch takes up 1.6 million square kilometers (618,000 square miles), an area more than twice the size of France. It contains 1.8 trillion pieces of plastic weighing in at 80,000 metric tons – equivalent to 500 jumbo jets.
Previous attempts to measure the Great Pacific Garbage Patch have mostly been done by single boats with trawls.
“We wanted to paint the entire picture,” said Joost Dubois, communications director of The Ocean Cleanup, the Dutch foundation which led the study. Their analysis was undertaken by a fleet of 30 boats crossing the patch and two planes fitted with sensors to measure larger items the vessels were unable to capture.
Around 8 million tons of plastic enter the oceans each year – the equivalent of dumping a garbage truck’s worth into the seas every minute for a year. Once in the ocean, much of this waste is pulled into huge areas known as the five “gyres” – one of which is the Great Pacific Garbage Patch – where circular currents allow the trash to accumulate, circulate and slowly break down.
As well as containing larger items, the garbage patch is also made up of microplastics (pieces of plastic smaller than 5 millimeters in size) that comprise around 8 percent of its total mass. Microplastics have increasingly come under the spotlight as these tiny fragments are thought to damage sea life. They are also entering the human food chain through fish and water ― impacting both tap water and bottled water. While the health implications aren’t fully understood, studies suggest that consuming microplastics could introduce toxic chemicals into the body.
Laurent Lebreton, lead author of the new study, said that while it wasn’t possible to draw firm conclusions on the persistency of the plastic problem in the Great Pacific Garbage Patch, the plastic accumulation rate “indicates that the inflow of plastic into the patch continues to exceed the outflow.”
George Leonard, chief scientist at Ocean Conservancy, an environmental nonprofit in Washington D.C. which wasn’t involved in the study, said that he was impressed with the extensive sampling and use of new techniques to try to quantify the problem.
“The one thing that really jumps out at me here is the fact that fishing gear makes up about half of the macro debris in the Pacific gyre,” he said. While microplastics pollution has been known for a while, bigger material in the ocean has been difficult to quantify, he said.
The debate about the global use of plastics is currently “largely focused on aspects of consumer plastic ― plastic bags and plastic straws and that kind of stuff,” Leonard added. “It’s pretty clear that if we really want to tackle this problem writ large, a focused effort on fishing gear and the loss of fishing gear in the global ocean has got to be a critical part of that strategy.”
The Ocean Cleanup has a bold plan to tackle plastic waste. “People expect [the garbage patch] to be like an island, or islands, of trash floating in this big area,” said Dubois. “The plastic is still spread out quite a lot over this big area so there is a lot of material but it’s also a very large surface.”
In an attempt to make collection economically feasible, The Ocean Cleanup is trying out a new technology involving autonomous booms like giant horseshoes, which float around the oceans powered by wind and currents.
“They basically follow the same pattern as the plastic does,” said Dubois, “but at a different speed, and because of the shape of the booms the plastic is being concentrated.” The plastic accumulates to a level “that it becomes economic to sail out, pick it up, bring it back to shore for recycling,” he added.
The first trial for the booms will happen in the next few weeks near San Francisco, before a planned trial in deeper water in May. The Ocean Cleanup hopes the system will be towed out to the Great Pacific Garbage Patch in the summer.
The organization estimates it can remove half of the area’s trash in five years, but admits microplastics will be too small for the new method to catch. “Although we won’t be able to collect the really bad stuff, we will collect an enormous amount of the stuff that will turn into bad stuff over time,” said Dubois.
The new study came out the day after another report predicted the amount of plastic in the ocean could triple by 2025.
That report, produced for the U.K. government, stressed that there are opportunities to be gained from the “ocean economy” if the seas are managed properly.
“The ocean is critical to our economic future,” Prof. Edward Hill, from the U.K. National Oceanography Center, told the BBC. “Nine billion people will be looking to the ocean for more food. Yet we know so little of what’s down there.”