The first manmade plastic (Bakelite) was created in 1907 to replace shellac and keep up with demand. So more than a century, although it’s hard to figure out when the real curve of mass plastic waste began to start climbing. Can’t be too far from then, once it hit commercial products it was everywhere, and the idea of consumerism and throwaway products wasn’t too long after then (thanks, Bernays).
The big wave was after 1950. This when our energy use and associated growth went into overdrive.
I wonder if microplastics can be found in older samples as well. Do microplastics predate industrialization? Not saying this is likely, but maybe we’re seeing something that was always there.
What we know is that they easily migrate into older sediment layers, so being less useful as dating markers.
