What it tells me is that things die off. No legislation, no whining about carbon, no new taxc is going to stop natural processes from doing their thing, and that includes going extinct. Paleocene, Pliocene, Miocene, Oligocene, Eocene, all had megafaunas vastly different from those in N America today, each of which died off without any human help, and would have done so in spite of any.
If any species is to break that well established pattern (over 98% of all species which have existed are dead), we'd best get our asses off planet and establish a presence that is not dependent on any one world to continue.