This is clearly a matter humans should be concerned with, as a matter of self-interest. The environment damages itself periodically, wiping out millions if not billions of species. Humans, however, wipe out species at a far greater rate. I think it is highly unlikely that humans are even capable at this point of destroying all life on this planet. From a global point of view, then, it seems arguable that humans can't to anything to truly destroy the environment.
Life seems simply too darned resilient, in some form or another.
In the evening, there was a variety show featuring various fannish talents singing and performing. It was entertaining, particularly the musical acts. And I bid on a couple of photographs in the art show - nice framed prints of some colorful mesa formations. They'd be nice to have on my wall, assuming I don't get out-bid. On the way home, I ran into a local fan who was going into the convention, and he said that for him the con starts when the programming is over.