Like millions of other people around the world I've been fascinated to hear five eminent speakers share with us their thoughts hopes and fears about sustainable development based on their own experience. All five of those contributions have been immensely thoughtful and challenging. There have been clear differences of opinion and of emphasis between the speakers but there have also been some important common themes, both implicit and explicit. One of those themes has been the suggestion that sustainable development is a matter of enlightened self-interest. Two of the speakers used this phrase and I don't believe that the other three would dissent from it, and nor would I.

Self-interest is a powerful motivating force for all of us, and if we can somehow convince ourselves that sustainable development is in all our interests then we will have taken a valuable first step towards achieving it. But self-interest comes in many competing guises - not all of which I fear are likely to lead in the right direction for very long, nor to embrace the manifold needs of future generations. I am convinced we will need to dig rather deeper to find the inspiration, sense of urgency and moral purpose required...