Plastic is durable—very, very durable—which is why we like it. Since it started being mass-produced in the 1950s, annual production has increased 300-fold. Because plastic is so durable, when our kids grow up and we purge our toy chests, or even just when we finish a bottle of laundry detergent or shampoo, it doesn’t actually go away. While we're recycling increasing amounts of plastic, a lot of it still ends up in the oceans.

Floating garbage patches have brought some attention to the issue of our contamination of the seas. But it's not just the waters themselves that have ended up cluttered with plastic. A recent survey shows that a staggering amount of our stuff is coming ashore on the extremely remote Henderson Island.

Henderson Island is a UNESCO World Heritage site in the Pitcairn Group of Islands in the South Pacific, roughly half way between New Zealand and Peru. According to UNESCO, Henderson is one of the best examples we have of an elevated coral atoll ecosystem. It was colonized by Polynesians between the 12th and 15th centuries but has been uninhabited by humans since then. It is of interest to evolutionary biologists because it has 10 plant species and four bird species that are only found there.

Despite its uninhabited status and its extremely remote location, a recent survey of beach plastic on Henderson Island revealed that the island has the highest density of debris reported anywhere in the world: an estimated minimum of 37.7 million items weighing 17.6 tons. This represents the total amount of plastic that is produced in the world every 1.98… seconds.

This is a conservative estimate of the debris accumulated on the island, since it includes only items that were at least two millimeters in size and were within the top 10 centimeters of sand. Up to 26 new items wash up every day per meter of beach.

There is no major land mass within a 5,000km radius of Henderson, so all of the plastic that ended up there originated from elsewhere on the globe. Plastic ends up in places like this because it is buoyant and can persist for decades as it is degraded into ever smaller particles by waves and sunlight. And global plastic production is still increasing, so this problem isn't going to go away. This plastic debris is bad for turtles, bad for shoreline invertebrates, bad for seabirds—and is also just gross.

The researchers who conducted the survey hope that this information will somehow help motivate us to limit plastic pollution. Once our plastic garbage is out of our sight, it tends to be out of our minds; but in fact, it congregates on isolated islands that, thanks to us, are now anything but pristine.

PNAS, 2017. DOI: 10.1073/pnas.1619818114 (About DOIs).