Global warming is real - and possibly even worse than we've been told. Could it lead to the destruction of human civilization within just a few decades? For tonight's Conversations With Great Minds - I'm joined by Guy McPherson -Professor Emeritus of Natural Resources - Ecology - and Evolutionary Biology at the University Arizona. Guy is one of America's most influential experts on global warming - and writes about a variety of climate change-related issues for the Arctic News and his own website - Nature Bats Last. In the field of climate science - Guy is best known for his assertion that runaway global warming is already on a path to cause the extinction of the human race - an idea he has written about in his book - "Going Dark."