By 2015, the world had produced 6,300 million metric tons of plastic waste. Of that, the 2017 study notes that only about 9 percent has been recycled.
More than 90% of the plastic waste has been buried in landfills, burned in incinerators or ended up littering lands, rivers and oceans.
Researchers from the National Oceanic and Atmospheric Administration have found that it takes from about 10 to 600 years for plastic objects to biodegrade in the environment.