New trends in physics teaching, v.4; The ... - unesdoc - Unesco

New Trends in Physics Teaching IV
the annual coal production goals of the United States government were 1.2 X 10' tonnes for
1980 and 2.1 X lo' tonnes for 1985. Consumption during 1976 was reported to be 0.60 X lo9
tonnes and the administration of President Carter set the goal of raising annual coal production
to 1 X 1 O9 tonnes by 1985 [ 91. From these data we can see that these goals called for an annual
increase in United States coal production of over 5 per cent per year.
r
1
L
m
ar
>.
a,
C
0
10:
10'
[D
P 10:
2
m
L
C
0
U
0
I)
U 0
a'
IO"
0'
E x p i r a t i on of ' tot a I re source i nc I u d in g -*
hypothetical' in the year 2000
4
/
-i
Expiration of 'total identified
resource' in the year 1987
/
/
/
/
I
Expiration of 'reserve base
in the year 1966
/
/
/
/
/
/
/
/
f
/-E,69 per cent per year
i
/
/
I I I 1 I I I
1870 1890 1910 1930 1950 1970 1990
Figure 3. History of United States coal production (redrawn from Hubbert [6a] 1. From the close of the American Civil War to
about the year 1910, coal production grew steadily at a rate that averaged 6.69 per cent per year. Production then levelled off
(with wide fluctuations) for 60 years and has now started to climb again. The crosses in the steep dashed curve at the right show
the coal production targets set by the Ford administration while the circle in the lower dashed line represents the production
goals of the Carter administration. The long dotted straight line shows what would have happened if the growth of consumption
had not stopped or slowed in 1910. The three triangles mark the expiry times (EETs) of Averitt's three estimates of United States
coal resources. Coal is an energy option for the United States in 1980 only because coal production had zero growth for 60 years
following 1910.
28