As far as modern science can ascertain the first organisms to appear on this planet were bacteria. And although bacteria are prone to mutation very little 'evolution' has occurred for as long as such things have been recorded. This is phenominal given they multiply exponentially. This means if you have one organism and it divides into two, and those two divide into two each. every generation you have double the number of the previous generation. Statistically the more times a living organism creates a new generation the chances of mutation increase, This mutation will then be passed on to all subsequent generations. These mutations are in some respects what we call 'evolution'. Given the speed at which bacteria create new generations in the space of a year we have ample time to study the changes over hundreds, thousands, millions and even billions of generations. We are quite confident very little 'evoltion' occurrs. This may be due to a key factor in evolution. If you have no hindering attributes there is is nothing to dilute out.
When we grow bacteria in agar (a gel of nutrients optimised for bacterial growth) and apply optimal heat. There are several phases the colony goes through.
1.Lag Phase, this is where the bacteria have just been introduced to the new conditions and take a little time to start dividing.
2.Log(arithmic) Phase. This is where the bacteria are dividing optimally and will reach peak rate of division.
3.Stationary Phase. This is where the toxins the bacteria produce have built up and are killing off the bacteria at an equal rate to the generation time.
4.Death phase. The toxins have mounted and are now killing the bacteria at a greater rate than generation time.
This assumes unlimited nutrition for the bacteria, however given the limitations on space the colony eventually eradicates itself. Now lets try and apply this to humans. Our population may not be exponentially increasing but it is certainly increasing at a steady and uncontrolled rate. We have limited space and nutrition available for our numbers. Eventually our waste will consume us. This is the greatest argument I can think of for going 'green'. It wont avert this fate but it stands a good chance of buying time.
Additionally if we assume as many do that the reason bacteria have changed little since the dawn of recordable time(we know this from ice samples extracted from the arctic and antarctic) is because they have little need to evolve past their current optimal state. This is directly related to how hardy they are. Humans however are still evolving, at an incredibly retarded rate. Modern medicine and technological advances eliminate 'survival of the fittest'. We have no preditors, and we have medicines for most ailments that would have eliminated the more vulnerable members of our species. This would suggest that we are far less able to survive our own fate.
Downsides to everything I've just said -
bacteria can survive with just one organism, Humans require two organisms short term, but a more diverse gene pool long term.
I make no apologies for my species. A random genetic mutation (or a series of) left us with aposable thumbs, I dont feel bad for eatting species that didnt develop this trait. Thats just nature.
I have had to simplify the science here greatly in order to make it digestible.
I will be posting more on this at a later time. I've just spent the day reading journals and my brain is fried. I hope this doesnt show too much in my writing.