By 1998, humanity was using the biological equivalent of one-fourth of Earth’s surface area, four percent more than the area taken up by land and three percent more than the amount that was ecologically productive.
By 2020, the amount of ecologically productive land will have grown to 24 percent of the planet’s surface area, while the amount used by humanity will have grown to 47 percent. In that year, like what happened to other species in 1975, our population will begin to decrease.
If our use of resources continues to increase after that, our population will continue dropping, approaching zero in 2048, when we would be annually using twice the amount we were at our peak, or nearly the entire surface of the Earth.
In an ideal world, we all would recognize these facts, and be taking appropriate action both further increase the amount of bio-productive land and shrink our consumption so that we and other species can live on that amount.
The rate of growth of resource use (including rendering unusable by waste) is falling, but not fast enough to avoid disaster. We are now using 167 percent of the bio-productive land we should be using to live sustainably with other species, which means that today we should be using 60 percent of the natural resources that we are. Each year we wait, if current trends continue, that fraction will decrease by about one percent, falling to 50 percent by 2014.