The Earth is already a giant recycling center. We manufacture plastic from Earth materials, that plastic is eventually eaten, degraded naturally, on the land and in the water.
I remember when the Deepwater Horizon oil spill occurred. There were ‘scientists’ who tried to questimate the total amount of oil that was released into the Gulf. After they determined an amount, they set off to find the huge underwater and surface oil. There was much less than expected. What real scientists found were huuuuge plumes of microorganisms that eat, yes eat, oil. A massive (more than huuuuge) amount of oil naturally seeps into the oceans from the ocean floor every year. IT’S PART OF THE EARTH. It is food for some parts of the Earth.
A quick search finds much information on our little buddies that dine on petroleum and plastic.
“”Natural and synthetic plastics are degraded by the action of microorganisms including bacteria, actinomycetes, and fungi (Ishigaki et al., 2004; Alshehrei, 2017).””
Many plastics are degraded by sunlight.