We are conditioned to think humanity is something sacred and extra special. But nature has dealt with plagues -like humans are these days, whether we admit it or not- before. And nature doesn't need us to debate and waste our breath. When and if necessary, it'll respond and deal out new cards. Whoever thinks the history of our planet is a story of perfect harmony and balance can stay in their idealistic ivory castle, and hopefully not witness inevitable change.
I think it is funny we think *WE* hold the destiny of earth in our hands. Like Douglas Adams put it, we're basically just primates wielding ever more sophisticated twig technology.
One thing is for sure: whether we believe in saving the environment or not, whether we believe in global warming or not... we humans do NOT control the fate of the planet. Volcanoes and earthquakes and hurricanes try to tell us to stay humble.
Personally, I'd like us to do more for the environment, because it seems the cautious smart approach. We do preventive maintenance in many areas *before* something breaks. It seems weird we are stil divided when it comes to tis issue, but hey, give it a few million years at most and whatever we do won't make a damn difference.