The 60 to 80 percent reduction in carbon dioxide emissions from fossil fuels required to deal with global warming corresponds to a global ecological footprint of 92 percent and 79 percent of the total amount available. If in 2004 we had ten years to achieve these reductions, then starting at the end of 2007 we would need to reduce total annual consumption by between 5.9 and 7.8 percent per year.
These rates would carry a human cost of 1.3 billion and 0.4 billion people, respectively; as population peaked and then dropped (compare this to the loss of at least 5.7 billion people if we do nothing). The Gross World Product (GWP) would level off at 88.8 and 81.8 trillion dollars, respectively, if we continued reducing consumption and the economy was tied to consumption as it has been for the last 40 years or so.
As I’ve suggested before, a more aggressive reduction in annual consumption of 17 percent per year (again, starting at the end of 2007) would remove the human cost altogether, with a peak GWP of 70.1 trillion dollars.