As population soars in a rapidly deteriorating global environment, it's hard to remain optimistic. We ask ourselves, what does it mean to have hope? Do we give up and fall into despair?

This is the question our two guests touch on in these interviews. Clive Hamilton is a the well-known author of books such as Requiem for a Species and Earthmasters. Robyn Williams is the renowned presenter of the ABC Science Show.

Interviews by Rod.