Exponential growth drives resource usage for a very simple reason:
Human population increases exponentially:
At the moment there seems to be very little that can be done about this and hence, this represents our fundamental problem. That is, you can't really stop it, only slow it down and plan accordingly.
Intelligent planning for exponential resource usage is directly related to environmental problem solving as follows:
The ability to discern amoung
the least bad alternatives is extremely difficult. Politics and
pseudo-experts come into play. Science can help, but still the
process is quite inexact. The New Carissa accident is a good
example of this.
"Math, formulas and other things that don't apply to real life"
(--anonymous comment from student evaluation of Physics 161 course
as the part they liked least about the course)
This again is a recipe for disaster as it means the public can be sold most anything
A survey of Boulder Colorado residents about the optimal size for growth returned a result that most residents thought that a growth in population at the rate of 10% per year was desirable.
Well 10% a year may not seem innocuous but let's see how these numbers would add up?
So in 7 years (year 2--7) the population has doubled and by then 10,000 new residents per year are moving to Boulder!
Clearly, Exponential growth, in general, is not understood by the lay public. If exponential use of a resource is not accounted for in planning - disaster can happen.
The difference between linear growth and exponential growth is astonishing.
In this example, one can clearly see that no matter what the growth rate is, exponential growth stars out being in a period of slow growth and then quickly changes over to rapid growth with a characteristic doubling time of
70/n years; n =% growth rate
Its important to recognize that even in the slow growth period, the use of the resource is exponential. If you fail to realize that, you will run out of the resource pretty fast:
|Aluminum||6.4%||2007 -- 2023||Coal||4.1%||2092 -- 2106||Cooper||4.6%||2001 -- 2020||Petroleum||3.9%||1997 -- 2017||Silver||2.7%||1989 -- 1997|
Exponential growth means that some quantity grows by a fixed percentage rate from one year to the next. A handy formula for calculating the doubling time for exponential growth is:
Doubling Time = 70/n years
where n is the percentage growth rate. Thus, if the growth rate is say 5%, the doubling time would be 14 years.
Try the Salmon Sustainability Applet
More Global Warming
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