48 THE SHADOW OF THE WORLD’S FUTURE
may be remitted to footnote! It will suffice here
to observe that had the human race started only
from a single pair, it could not increase at I per
cent. per annum for 10,000 years, for this would
require over 248 million million million of our earths
to provide material for their bodies. We see how
misleading popular conceptions are as to what is
¢ In order to estimate the exact population-effect of various annual
rates of increase, from one-half per cent. per annum to 4 per cent,
the following table is of service :—
Annual increase
LER “}os ro 1 20 25 30 35 40
Years to double 128-96 69-66 46°36 35-00 28-07 23°45 20°15 17-67
from this last table one sees at once the consequences of any par-
dcular rate. This, however, involves some calculation. It is more
simple to have a table showing, for various date-years, the populaton
to which the world will have attained should certain rates be char-
acteristic of its growth. For this table, given hereunder, we have
taken the population for 1928 as about 1950 millions. ‘The numbers
are millions.
DrveLopMENT oF PopuraTioN aT Various RATES oF
INCREASE PER CENT. PER YEAR
Year .
Rate . 0-5
» , 078
9 » IC
p «I?
3% 100
a
1930 1050
1970 2/77
1079 2298 I 0
909 2427 3+.
a 2563 24c0
J 2700 Gy20
8
2000
2025
2702 2163
339 4025
lg92 511g Bo
4770 607
c6gt 0265 i
r Iadoto]
3
32
2075 2100
4,059
4,598
2549 7,050
419 10,797
roa* 16,519
25,246
¢ The populations marked with asterisks are not possible for the earth.
The evidence of such a table as this is startling, for it will be noticed
that the rates in the table are well within those of the quinquennium
1906 to 1911. Increase, even at the average rate of 1-16 per cent. per
annum, cannot last for any length of time, or at the rates of England
and Wales, Japan, Ceylon, Switzerland, the Netherlands, Denmark,
or Germany, to say nothing of any greater rates. This fact is one that
is not commonly realised. It is very significant that the consequences
of increase at a continuous and even small rate, over quite moderate
periods of time, are not visualised in our everyday thinking. Prob-
ably no one, who has not given the matter quite special attention,
would be at all startled if he read somewhere that, during the his-
