[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