Exponential Growth:
Plotting and Analogy
One reason that we have an energy problem is due to exponential
growth which creates a strongly non-equilbrium use of our resources.
(You wouldn't know we have an energy problem if you look at traffic
at 5:00 p.m.)
Its not to great of simplification to state that the failure to
understand the concept of exponential growth by planners and/or
legislators, is the single biggest problem in all of Environmental
Studies and/or Management.
The Two Principle Problems with Energy Management:
- Failure for policy makers to understand the
concept of exponential growth.
- Failure for legislation to be formulated and
passed to give us a long term energy strategy
Exponential growth drives resource usage for a very simple
reason:
Human population increases exponentially:
Accurate trend extrapolation is the most important part of future
planning. However, failure to assume exponential growth will always
lead to a disaster
so always assume exponential growth when planning anything!
In this example, one can clearly see that no matter what the
growth rate is, exponential growth starts out being in a period of
slow growth and then quickly changes over to rapid growth with a
characteristic doubling time of
Doubling Time (D.T.) = (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:
Anytime growth depends
upon a percentage on some amount that already exists we get
Exponential Growth.
Exercise I. The Data Below was plotted
in class using Excel Spreadsheet
Data Table
Number of Doubling
Times
|
Amount of Stuff
|
0
|
1
|
1
|
2
|
2
|
4
|
3
|
8
|
4
|
16
|
5
|
32
|
6
|
64
|
7
|
128
|
8
|
252
|
9
|
512
|
10
|
1024
|
Graph of above
Data:
Same Data Logarithmic Graph: Linear
Relationship
Exercise II.
Exponential Use: Analogy of the use of Natural Resources with
Exponential Growth.
(Not totally accurate but any similarity
between this analogy and reality is planned.)
- 500 unit Flask Represents Oil (
U.S. Reserves)
- Rate: Increase of consumption is
5%, 14 years doubling time.
- Start Date 1954: we used 200 units of Oil up to this time.
- Between 1954 - 1968, we used 400 units of oil. Note U.S. Reserves are decreasing. Find More Reserves: Middle East (Bigger 1000 unit Container)
- 1968 - 1982 another 800 units is used. This is more than the total 300 units used since we began using and 1968. A characteristic of Exponential Growth is: The amount used in
one doubling time exceeds the total amount previously
used.
- Mine oil in Alaska, mine in the
North Atlantic, have a war etc. Look at what we found!!! Big
Container. Lets make money!!! Keep the price down, sell it fast!!
We have to have growth to survive. Keep it at 5%!! No Problem.
Look How much oil we have!!
- 1982-1996: Another 1600 units is used ( Double the amount previously used) Looks like we may be running a bit low. (Is the flask half empty , half full, or just dirty.)
- How much do we need to make another 14 years? 3200 Units Again more than we used in all of history. (Pull out big container that has the stuff we have used so far). When do we think we are running out of oil??? This is a Big Container of stuff!! It looks like we have plenty but the rate of usage will use up the container that contains the same amount that we used in all of history in 14 years.
- We would probably wake up when over
half that big container is used up. Result: No more 4x4 vehicles
to drive to the grocery store. That's another
story.....
- Respectfully Submitted: Stan
Micklavzina