Science Questions

We’re using the energy at the moment, per person, of three Earths. How much energy does the Earth produce for a person to use every single day? Matt

Chris: The Geo4 paper came out this month and this is a big, multi-national report where scientists get together from every country in the world. They look at the raw data and work out where the Earth’s going and how it’s ‘powering’ itself. Their current calculations show that the current environmental demand, or how much land it takes to power each person on Earth, is about 22ha of land surface per person. How much can the Earth sustainably supply in the long-term? The Earth can only support humans sustainably on 15.7ha of land per person. We’re already using the land space, per person, of two Earths just in terms of land space. If you look at fishing the amount of exploitation of the oceans is thought to be 250% of sustainable levels of fishing in the long-term.

Victoria: That really puts into perspective how much extra land we’re going to need for biofuels as well.

Chris: The other point they make is that in about forty years time they think the Third World will need land space equivalent to the entire of South Africa for producing enough food just to support the extra people that the planet is sustaining by then.

November 2007