The following is part of an article by Patrick Dery and Bart Anderson on Energybulletin.net
“Peak oil has made us aware that many of the resources on which civilization depends are limited.
“M. King Hubbert, a geophysicist for Shell Oil, found that oil production over time followed a curve that was roughly bell-shaped. He correctly predicted that oil production in the lower 48 states would peak in 1970. Other analysts following Hubbert’s methods are predicting a peak in oil production early this century.
“The depletion analysis pioneered by Hubbert can be applied to other non-renewable resources. Analysts have looked at peak production for resouces such as natural gas, coal and uranium.
“In this paper, Patrick Déry applies Hubbert’s methods to a very special non-renewable resource - phosphorus - a nutrient essential for agriculture.
“In the literature, estimates before we “run out” of phosphorus range from 50 to 130 years. This date is conveniently far enough in the future so that immediate action does not seem necessary. However, as we know from peak oil analysis, trouble begins not when we “run out” of a resource, but when production peaks. From that point onward, the resource becomes more difficult to extract and more expensive…”
This is just another example of the way that we have raised the carrying capacity of the Earth to a level that is not sustainable. We must look at ways to recycle phosphates and other nutrients instead of flushing them down the sewers of the big cities.