Guardian: Every crisis, Sigmund Freud said, is potentially a stimulus to the positive side of the personality and an opportunity to start afresh. Today we are facing two global crises in tandem – the economic recession and climate change. Both are deeply worrying, but what is their relationship likely to be? Freud’s point has not gone unnoticed by the scientists gathering in Copenhagen this week, nor by political leaders. Following the example of Barack Obama, many have signed up to the idea of …