Since 1950, industry has made more than 9.1 billions of tons of plastics. But plastic doesn’t degrade like other, more natural, materials, so now there’s enough of it left over to bury Manhattan in over 2 miles of plastic waste.

This news comes from an article in the journal Science Advances.

The researchers combined plastic production data with product lifetime distributions for eight different product categories, to model how long they are in use before they reach the end of their useful lifetimes and are discarded. In doing so, they were able to present the first global analysis of all mass-produced plastics ever made.

Plastic began to be produced in mass quantities after World War II. They’re used in everything from packaging to cell phones, cars to toys, and construction supplies to clothing.

In 2015, the world created 448 million tons of plastic. That’s more than twice the amount that was made 15 years ago.

“The growth is astonishing, and it doesn’t look like it’s slowing down soon,” said study lead author Roland Geyer of the University of California, Santa Barbara.

China makes the most plastic—not surprising, since so many things are manufactured in that country—followed by Europe and North America.

According to industry representatives, plastics manufacturers recognize the problem and are working to reduce waste and increase recycling.

“Plastics are used because they are efficient, they are cost-effective, and they do their jobs,” Steve Russell, vice president of plastics for the American Chemistry Council, told the Associated Press. “And if we didn’t have them, the impact on the environment would be worse.”

Plastic waste in water harms hundreds of species of marine life, including whales, dolphins, fish, sea birds, and sea turtles.

We’ve already written at great length about how plastic waste ends up in the world’s oceans, lakes, and rivers—and even in the world’s most remote islands. But that there’s so much of it left floating around and sitting in the world’s landfills is truly alarming.

“The fact that it becomes waste so quickly and that it’s persistent is why it’s piling up in the environment,” said University of Toronto ecology professor Chelsea Rochman. “At some point we will run out of room to put it. Some may argue we already have, and now it’s found in every nook and cranny of our oceans.”