What a waste.

Humans have produced 18.2 trillion pounds of plastics since large-scale production began in the early 1950s and we've put most of it in the trash.

That weight is equivalent to 1 billion elephants or 25,000 Empire State Buildings. Nearly 80% of that plastic now resides in landfills or the natural environment, according to a study published Wednesday.

And we’re just getting started: Scientists say that by 2050, another 26.5 trillion pounds will be produced worldwide.

"Most plastics don't biodegrade in any meaningful sense, so the plastic waste humans have generated could be with us for hundreds or even thousands of years," said Jenna Jambeck, study co-author and associate professor of engineering at the University of Georgia.

"You can’t go anywhere without finding plastic waste in our environment, including our oceans,” she said.

A separate, recent study by the British research firm Eunomia said there may be as much as 70 million tons of plastic waste on the sea floor alone.

The study is the first global analysis of the production, use and fate of all plastics ever made. It found only about 9% of plastic has been recycled. Another 12% is incinerated.

Researchers said plastic is also one of the most produced man-made materials, behind only steel and concrete.

The difference is that "roughly half of all the steel we make goes into construction, so it will have decades of use. Plastic is the opposite," said study lead author Roland Geyer of the University of California, Santa Barbara. "Half of all plastics become waste after four or fewer years of use."

China, the U.S. and Europe produce the most plastic, Geyer said. "The best recyclers are Europe and China, but sadly, not the U.S.," he added.

The largest market for plastic is packaging, which increased worldwide as consumers shifted from reusable to single-use containers.

Overall, the share of plastics in municipal solid waste increased from less than 1% in 1960 to more than 10% by 2005 in middle- and high-income countries. Plastic debris has been found in all major ocean basins in the world.

The scientists say they know that plastic production isn't going to stop or even slow down.

"There are areas where plastics are indispensable, especially in products designed for durability," said paper co-author Kara Lavender Law, a research professor of the Sea Education Association. "But I think we need to take a careful look at our expansive use of plastics and ask when the use of these materials does or does not make sense."

The study was published in the peer-reviewed journal Science Advances, a publication of the American Association for the Advancement of Science.