"Cocos is literally drowning in plastic, which is really sad considering how incredibly remote these islands are," Lavers, the study's lead author, said in an interview released by the university. "Most of the beaches are inundated with plastic."
The study's findings come two years after Lavers discovered a similar problem on Henderson Island, a remote island in the South Pacific Ocean.
Data from both Cocos and Henderson not only reflect the global consumption patterns of disposable plastics, but also suggest previous surveys that focused only on visible surface waste may have "drastically underestimated the scale of debris accumulation," researchers wrote.
The scientists studied more than two-dozen beaches across seven of the 27 islands that make up the Australian atolls, a process that included digging about four inches into the sand, where they continued to find bits of plastic rubbish.
"The quantity of debris buried below the surface was so significant," Lavers told the Washington Post. "It ended up accounting for more than 90 per cent of the total debris on the island. That's really quite remarkable."
Researchers estimate that about 238 tonnes of plastic washed up on beaches that are exposed to ocean currents, wind and waves. Remote islands are "extremely valuable" to scientists because they can provide "a complete picture of how much is out there, where it's coming from and the types of problematic items," Lavers said.
In evaluating the garbage, Lavers and her team found 373,000 toothbrushes and 977,000 shoes. It would take the population of Cocos 4000 years to produce an equivalent amount of rubbish, the study said.
"They did not create this problem and they cannot undo it on their own," Lavers said.
In videos taken of the isolated beaches, hermit crabs could be seen scuttling among discarded flip-flops and crumpled bottles. Nearby, clumps of sun-bleached rope lay tangled in what appeared to be fishing nets.
"What the remote island data collection has shown us is that the quantity of plastics in the ocean is going up, and going up very rapidly," Lavers said.
According to a 2014 study, oceans contain an estimated 5.25 trillion pieces of plastic - an amount greater than the number of stars in the Milky Way. During the Ocean Conservancy's 2017 International Coastal Cleanup, the nonprofit environmental group reported that volunteers picked up enough plastic bottles to fill five standard swimming pools and enough straws to reach the height of more than 10,000 palm trees.
But those statistics aren't the full picture, Lavers said.
"What Cocos and Henderson show us is that however stunning those numbers are, how alarming they are, it's likely just the tip of the iceberg," she said. "None of those cleanups are digging below the surface."
Lavers added that the data gathered from the Cocos Islands also probably falls short of reality. During the trip, the researchers were unable to access two of the "known debris hot spots" and while the distance they dug was the standard, it was "not very deep," she said.
"The numbers I put forth . . . are undoubtedly underestimates of the true extent of the problem," she said.
Though the world may just be learning of the islands' plight, the Cocos Malay people have long been aware that formerly untouched parts of their home have gradually become dumping grounds, Lavers said. Rather than attempt to hide the pollution, they've been doing what they can to draw attention to it.
"They take their tourists directly to the accumulation zones, specifically so they can have meaningful and honest conversations," she said. "Every tourist leaves a better and changed person."
Residents have also attempted the Sisyphean task of trying to restore their beaches with cleanups. While the researchers were there, Lavers said 50 people "descended" on the islands, working with volunteers from the local school to tidy more than 20km of beach and remove tens of thousands of plastic items. Local artists have even taken some of the plastic and used it in their work, she said.
The buildup of garbage on islands like Cocos, however, is preventable if people are willing to change aspects of their daily life, Lavers said.
"I hope that these places provide them with the visual evidence that they need to be convinced to make better, more informed decisions," she said.
A number of these changes, which include shopping with reusable bags or no longer using plastic straws, are both easy and quick, Lavers said.
"They're not going to dig us out of this, but they're still worthwhile," she said. "So get the bamboo toothbrush and feel good about it."