[svnt]

Your definition involves setting humanity apart from nature and then inverting the implicit superiority in doing that. Once you’ve taken those steps you can say anything people make that isn’t made by other animals is worse because it is unnatural.

To me the essential idea is we have the scale and capacity to move global homeostasis in ways that few animals (at least since dinosaurs) have.

Plastics are not unnatural. They are produced by animals. Humans are animals. Just more dangerous than others on a global scale.

Wax moths and bacteria both have already naturally mutated and evolved to consume plastics. Evolution and life are perhaps less fragile than you think.

None of this is to say we shouldn’t behave responsibly, only to say we also shouldn’t panic every time someone creates something that kills some stuff. That too is natural, and drives evolution.

[alexvoda]

Exactly as parent stated, there already are organisms evolving to consume plastic. The same is probable to happen for PFAS. It has carbon therefore it contains useful energy that some creature will eventually evolve to digest and outcompete other organisms.

That of course is to the detriment of the very properties we desire in these materials. Just as flooding the environment with antibiotics made them less effective, so will flooding the world with plastic will make plastic lose it's advantages. Just more slowly. This is another reason to not contaminate the environment with our externalities.

[grog454]

It's useful to distinguish things that are made with human influence and things that aren't, and it can be done without value judgments (one is superior or inferior). It's useful because of the disproportionate effect of synthetic things vs. natural things. No species prior to humans had the ability to obliterate all life on earth.

[alexvoda]

On the contrary, some species have already obliterated most other life on earth namely cyanobacteria during the great oxigenation event. Possibly others have done the same. They certainly did not care at all about the destruction they caused. All of this was perfectly "natural".

That of course does not mean we should follow their example. It just means that "natural" is not a useful term.

[grog454]

This is still a far cry from a global nuclear winter or a deliberately redirected asteroid, or any other number of things that only humans are capable of.

[alexvoda]

The Great Oxigenation Event is a terraforming level event. We are not yet capable of such a large scale manipulation. Nuclear winter is at most comparable to a supervolcano or an asteroid impact.

Also, if you consider asteroids to be natural and their orbits to be natural then "nature" is already plenty capable of playing cosmic billiards. Or do you want to restrict nature to just biology?

[dcow]

Is life natural?

[LesZedCB]

insufficient data for meaningful answer