Study after study has illustrated the insane amount of plastic clogging up our planet. But a new one focusing on Australia's Cocos Islands suggests we still may have greatly underestimated the problem. Researchers surveyed 88% of the total landmass of the remote islands considered "Australia's last unspoilt paradise" and found an estimated 414 million pieces of plastic debris—including an estimated 373,000 toothbrushes and 977,000 shoes—weighing 262 tons, per CNN. Some 93% of that debris, mostly microplastics, was buried up to 4 inches below the surface, which is as far as researchers dug. "This suggests global debris surveys, the majority of which are focused solely on surface debris, have drastically underestimated the scale of debris accumulation," reads the study published Thursday in the journal Scientific Reports.
Study author Jennifer Lavers of the University of Tasmania says even her figures are "conservative." Researchers only scratched the surface of the islands home to 500 people—finding 25% of the debris came from single-use consumer items, per NBC News—and "couldn't access some beaches that are known debris 'hotspots,'" she says in a statement, describing such islands as "canaries in a coal mine." As there are now thought to be more plastic pieces in the ocean than there are stars in the Milky Way—5.25 trillion—"cleaning up our oceans is currently not possible," says co-author Annett Finger. "The only viable solution is to reduce plastic production and consumption while improving waste management to stop this material entering our oceans in the first place." (The team previously identified an uninhabited island as among the world's most polluted.)