> So the fact that we are having an unforeseen impact on the environment should be cause for concern, if not alarm.

The environment has never been stable, not once in the history of the environment. It is constantly changing. The only way we could avoid having an unforeseen impact is if we wipe the environment out.

As is stands, we're having a milder impact than one of the big ones like blue-green algae and the oxygen crisis. I'd go as far as saying the hermit crabs are pretty happy with how this situation is developing. Plastic shells sound like a pretty high tech option for the happening hermit.