Slaar and I were talking about ecological footprints on another thread. Here's some
footprint data from Rio (ie it's a few years old)
Let's take the UK as an example, leaving the global stuff above to one side for the moment. According to the Rio figures, the UK is -3.5 overshot. That is, it has three and a half ha per person less land than it needs to actually feed in the abscence of any plentiful supplies of cheap oil for transport, and the chemical manufacture of pesticides and fertiliser. Most importantly, phosphorus needs to be mined in a distant part of the world, industrially processed and applied to depleted soil.
If you look at the figures from Pimentel above, who is assuming in effect some variation of business as usual only with biofuels and all that kind of stuff. I.e. pretty much the estalishment account of how we are likely to deal with these issues in the future. Use those numbers, and the situation looks far worse than a threefold overshoot. Please feel free to check my calculation here.
Area of UK = 94,525 Square Miles
Arable Area = 24,964 Square Miles
Actual UK Pop = 60,000,000 People
Pimentel makes the following assumptions:
Land needed per cap for growing food = 0.5ha
Land needed per cap for energy/biomass = 1.5ha
Land needed per cap for biodiversity/pasture = 1ha
Total = 3ha = 7.41 acres = 0.011578125 Square Miles, therefore:
694,687 arable Square Miles needed to support the present UK pop. We divide by the actual number of arable sq miles to get the overshoot and discover we're about
27 to 28 times overshot.
Not good. We can get some better numbers if we use Folke Gunther's assumptions above. He's actively re-designing how we live, so as to cut as much as possible of the energy requirement.
He comes up with a requirement of about 0.25ha per person, which means an overshoot of 2 to 3 times, but he does this by making very radical assumptions, involving massive changes to reduce the energy burden, in effect by putting everybody within a few miles of where their food is grown and doing away with
all public sewage systems to replace them with sustainable ones.
Conclusions suggested? The business as usual with ecofuels option doesn't look terribly viable for the UK at least, unless you also assume that the US is going to share nicely the remaining reserves, should it end up controlling them in a decade or two.
The radical option looks a lot better, but still pretty desperate. The difficulty with that option is trying to imagine any set of circumstances where it could end up be applied on a UK scale.