Famed conservationist E.O. Wilson says climate change is a threat. But he also worries about the Republican nominee and people with nuclear codes.

Maybe it's because the word refers to the ultimate oblivion, or maybe it's because most of us think of polar bears stranded on melting icebergs when we hear about "extinction," but many of us assume the curtailing of life forever is a remote phenomenon.

We're focusing on the nonliving, physical environment. "But Earth's living environment, including all its species and all the ecosystems they compose," is receiving little attention.