[javajosh]

What do you mean? The expansion of the sun, or a meteor strike, or a caldera explosion, something like that? Well, yes of course those are all likely on some large time scale, but they are entirely out of our control. Meanwhile we have every likelihood of having a 1M year existence, as a species embedded in a biosphere, if we can "get on the same page" with respect to our behavior. I propose that we adopt the universal rule that we all act "consistent with our survival, and that of our species" in an exact analogue to Issac Asimov's Zeroeth law of robotics. It is a small jump from that to the protection of the biosphere in general, if you are willing to ignore the strong emotional pull of science fantasy narratives that imply that we can survive without it.