# "We used 10 times as much energy in the 20th century as inthe 1,000 previous years"

Charles Brown CharlesB at SPAMCNCL.ci.detroit.mi.us
Tue Jun 27 10:20:50 MDT 2000

```Mark,

Isn't this arithmetic of exponentiality pretty much the same as that of compounded
interest or compounded GDP growth ?

Charles

>>> jones118 at lineone.net 06/26/00 03:21PM >>>

TABLE  I
Lifetimes of non-renewable resources for different rates of growth of
consumption. Except for the left column, all numbers are lifetimes in years.

0 %    10   30  100  300  1000   3000   10,000

1 %    9.5  26   69  139   240    343      462

2 %    9.1  24   55   97   152    206      265

3 %    8.7  21   46   77   115    150      190

4 %    8.4  20   40   64    93    120      150

5 %    8.1  18   36   56    79    100      124

6 %    7.8  17   32   49    69     87      107

7 %    7.6  16   30   44    61     77       94

8 %    7.3  15   28   40    55     69       84

9 %    7.1  15   26   37    50     62       76

10 %   6.9  14   24   34    46     57       69

Example 1.  If a resource would last  300 years at present rates of
consumption, then it would last 49 years if the rate of consumption grew  6
% per year.
Example 2.  If a resource would last  18  years at  5 %  annual growth in
the rate of consumption, then it would last  30 years at present rates of
consumption. (0 % growth)

Example 3.  If a resource would last  55 years at  8 %  annual growth in the
rate of consumption, then it would last  115 years at 3 % annual growth
rate.

```