Inspired by photos of our planet, like a beautiful jewel in the inky blackness of space, taken by Apollo astronauts on their way to the Moon or from its surface, the concept of Spaceship Earth has been with us for some time. Just like any spaceship, Earth too has limited resources and vulnerable life-support systems with a finite carrying capacity.

I remember when about 30 years ago an explosion on board Apollo13, on its way to the Moon, seriously damaged that spaceship's life-support systems and threatened the survival of its crew. Although on a very different scale (what took just a few seconds to become apparent on Apollo 13 is taking decades on Spaceship Earth) our situation is very similar; in fact, we are even more vulnerable - since, unlike the Apollo astronauts, we have nowhere to get back to. If we seriously overload or damage our planet's life-support systems, which, given current economic philosophy, our materialistic aspirations and lifestyles, and an expected world population of 8 - 10 billion, we are bound to do, we (or our children) will soon be in deadly serious trouble.

The immortal words of Apollo Commander, James Lovell, "Houston, we have a problem." apply equally well to our Spaceship Earth. Only we have to solve the problem (creating sustainable economies and lifestyles for 8 - 10 billion people) on board ship - or perish.

We have not yet faced up to it, but solving the problem will require radical changes to our economic system and materialistic lifestyles. The Kyoto protocol, even if it is ratified and implemented, barely scratches the surface of the problem. The solution requires us to question the values, attitudes and aspirations on which our non-sustainable economy and lifestyles are based, and to begin changing them in the direction of sustainability.

We need a sustainable economic philosophy and role models for sustainable lifestyles, perhaps a new religion, a set of beliefs and values that would bind together those of us prepared to do what is necessary to achieve sustainability; a religion that emphasises man's responsibility for what he does (particularly in respect to how he earns, spends and invests his money) rather than his guilt for having aspired to greater awareness and knowledge, and that focuses on creating a truly humane, democratic, just, and sustainable society here on Earth rather than on rewards in a supposed afterlife.