The earth's ability to assimilate atmospheric carbon constitutes less than half our demand on our already over-exploited natural systems. Even If we could reduce carbon emissions to zero, true sustainability and ecological justice would still be distant ideals.

If we do accept the idea of biophysical constraints on the existence of humans on earth, some important questions arise - such as.
- What is my share of the ecological commons?
- If I don't know, should I find out?
- Can I live a meaningful, moral life by knowingly taking more than my share?
- What will my life be like if I live truthfully and take only what is due to me?

These are challenging questions that tap into needs deep within every human person - the need to be of service to others, to play our role well, to leave things as good as, or better than we found them and, most importantly, not take more than our share. I believe the answers will come naturally to us in the same way a child at a birthday party knows and accepts, that if there are eight pieces of cake and seven other children, the fair share is one piece each.

I believe individuals, when made aware of their ecological entitlement, are capable of this quantum shift in thinking. The shift will be driven by a recognition of our humanity and an awareness that every consumption decision we make will impact on someone else, some time, somewhere on our finite Earth.

We don't need an increased supply of energy and resources, these are not a supply side problems. They're demand side problems. We need to do as the ancient Greek philosopher Socrates said, that is: to live an examined life. To be aware of our ecological entitlement and our common humanity. If we do this, we will see answers such as P.V. panels on our roofs and smaller more energy efficient cars and houses as a source of pleasure to us rather than sacrifices we have to make under sufferance.