I agree that we do have trouble managing the environment properly. I sincerely hope, for the sake of my child and all the children of the world, that we will change our ways and be capable of living on our beautiful planet without destroying it and ourselves.
But, even if we do, we still have to find another home, lest we become the next dinosaurs when (not if) that rock comes blazing down.
The survival of our species demands that we colonize other worlds. We certainly can do it in a respectful manner as far as natural resources are concerned. We have the technology, and the tech that we're missing we will create - I am certain of that.
We are not that bad, it's just the news that makes us look like we are terrible. We should expand. Not like locusts, but like stewards - responsible and respectful of Mother Nature and her resources, and always in awe of the wonders of our Universe.