The purpose of this board is to discuss the ascent, peak, and decline of natural resources. Decline implies depletion and can be defined as follows:
[From Wikipedia, the free encyclopedia]
"Resource depletion is an economic term referring to the exhaustion of raw materials within a region. Resources are commonly divided between renewable resources and non-renewable resources. Use of either of these forms of resources beyond their rate of replacement is considered to be resource depletion.
Resource depletion is most commonly used in reference to the farming, fishing, mining, and fossil fuels.
Normally, resources will not become totally exhausted at some particular moment, but rather will diminish until the price of continued exploitation becomes so high that it is no longer economical. According to Hubbert peak theory, the rate of exploitation follows a sort of bell-shaped curve. The Hubbert peak theory article discusses predictions for some resources.
Estimates for when various resources will run out if exploitation continues at present rates are somewhat controversial, but for some resources, the estimated time left is rather short."[1]
[1]"Earth's natural wealth: an audit" by David Cohen, New Scientist, 23 May, 2007, pp. 34-41.
Peak Everything: Eight Things We Are Running Out Of And Why
http://www.treehugger.com/files/2008/05/peak-everything-8-things-we-are-running-out-of.php