6.3 billion tonnes of plastic waste generated globally to 2015

A new report estimates that from 1950 through 2015 approximately 6.3 billion tonnes (6,300 Mt or metric tonnes) of plastic waste had been generated globally . In total the study estimates 8.3 billion tonnes (8,300 Mt) of plastics have been produced globally since 1950, which marks the beginning of mass production of plastics.  The report published in ScienceAdvances provides the first peer reviewed global analysis of all mass-produced plastics ever manufactured, along with data on the production, use and end-of-life management of polymer resins, synthetic fibers, and additives.
Of the approximately 6.3 billion tonnes of plastic waste, approximately 800 Mt (12%) have been incinerated and 600 Mt (9%) have been recycled, some 10% of which have been recycled more than once. Around 4,900 Mt (60%) have been discarded and are accumulating in landfills or in the natural environment. The authors note that the vast majority of monomers used to make plastics, such as ethylene and propylene, are derived from fossil hydrocarbons. None of the commonly used plastics are biodegradable. As a result, they accumulate, rather than decompose, in landfills or the natural environment. The only way to permanently eliminate plastic waste is by destructive thermal treatment. None of the mass-produced plastics biodegrade in any meaningful way, however sunlight weakens the materials, causing fragmentation into particles known to reach millimeters or micrometers in size.
The authors note that the vast majority of monomers used to make plastics, such as ethylene and propylene, are derived from fossil hydrocarbons. None of the commonly used plastics are biodegradable. As a result, the near-permanent contamination of the natural environment with plastic waste is a growing concern. Plastic debris has been found in all major ocean basins with an estimated 4 to 12 million metric tonnes of plastic waste generated on land entering the marine environment in 2010 alone.
Global production of resins and fibers increased from 2 Mt in 1950 to 380 Mt in 2015, a compound annual growth rate (CAGR) of 8.4% which is roughly 2.5 times the CAGR of the global gross domestic product during that period. The total amount of resins and fibers manufactured from 1950 through 2015 is 7800 Mt and half of this (or 3,900 t) was produced in just the past 13 years. Bio-based or biodegradable plastics currently have a global production capacity of only 4 Mt and were excluded from the analysis.
Global recycling and incineration rates have slowly increased to account for 18 and 24%, respectively, of nonfiber plastic waste generated in 2014.
The authors note the same properties that make plastics so versatile in innumerable applications (durability and resistance to degradation) make these materials difficult or impossible for nature to assimilate.

Production, use, and fate of all plastics ever made
Geyer, Jambeck and Law.  Science Advances 19 Jul 2017: Vol. 3, no. 7