What's the "proper" environmental impact?

An article on Slashdot about solar panels and the subsequent obvious comments arguing about the impact of these panels vs. fossil fuels got me to thinking: What's the "proper" environmental impact for a human being?

We can all agree on the negative extreme. Polluting groundwater with heavy metals or pumping enough pollution into Lake Erie to nearly sterilize it is bad. Hardly requires thought. But as you start getting back away from that, it gets a lot more complicated.

It seems to me that there are two major standards being applied, unexamined:

  1. A human should make no environmental impact; any difference from "the human never existed" is presumed bad.
  2. A human should never take from any other organism; anything that takes resources from another organism, be it land to live on, food to eat, etc. is bad.

Upon conscious examination, it should be obvious that both of these are as objectively absurd as you could ask for. Why? Because no other organism on Earth can meet either of these criteria. All organisms have impact, almost by definition. All organisms take from other organisms; life is nothing but a constant fight for survival and only the abundant resources we've found and even created for our species has shielded us from that reality. I reject any environmental impact standard so strict that it is unmeetable by any living organism.

On a similar note, I am suspicious of any standard which would declare that first photosynthetic organisms, which are arguably responsible for the single greatest life-caused mass extinction in Earth's history when they loaded the atmosphere with that incredibly toxic gas we call oxygen, should have been stopped at all costs. Stasis also falls down as a criterion when examined critically.

I've been pondering this in the back of my head for about half an hour now, and I don't have a clue as to how to even begin defining a "proper environmental footprint" in anything like traditional terms. This probably goes a long way towards explaining the effectively religious arguments on the topic.

It all comes down to a question of valuation; how do you value one ecosystem in relation to another ecosystem? That's mighty tricky, even when you don't view nature excessively romantically.

Making it even more complex is the fact that man is the biosphere's last, best hope to get off the planet. If Man spreads life abundant out into the vast desolate wastes of space, then from an economic viewpoint anything done to Earth can be forgiven, even total sterilization (after such massive space colonization). If some future event not caused by man is going to cause a mass extinction anyhow (asteroid strike or something), does any "damage" done really matter? Economic arguments are basically impossible to make because the future has effectively infinite uncertainty within the next two or three centuries, which is still a geological blink of an eye.

So... my conclusion is that we probably can't define "proper environmental impact", and in lieu of that, the best policy is probably to make reasonable efforts to minimize the impact, but one need not feel guilty about existing, or allow people to manipulate you on that basis. Which I suppose comes down to nothing more and nothing less than the Golden Rule.