Is the World Population Explosion Really
Over?
Many journalists now assume that the "population bomb" has been
"defused." But the assumption isn't supported by hard facts. Here are a few
essential points to consider:
Growth rates in the industrialized world should not be confused with population
growth rates in developing countries.
Birth rates are quite low in the developed countries, particularly in Europe,
where women average only 1.4 children, but these countries were never part of the postwar
population "explosion."
90 percent of world population growth since 1950 has been in the developing
countries.
Today, 98 percent of population growth occurs in the developing countries. This
situation will continue for the foreseeable future.
A basic demographic measure is the total fertility rate
(TFR),
the average number of children a woman has during her lifetime. For population size to
stabilize in the future, women must average about two children each, a fertility rate
demographers call the replacement level.
In all developing countries except China, women average four children, twice the
level needed for a stabilized population size. In Africa, the TFR is six.
It is likely that growth in world population over the next 50 years will equal
or exceed that of the last 50 years.
All population projections are performed the same way. Demographers must make
assumptions about fertility (the birth rate) and mortality (life expectancy) to project
future population size.
Small differences in the assumptions about fertility from one projection to
another can make large differences in projected population sizes.
For example, long-range UN projections for Africa show that the continent's
population size would increase from the present 0.8 billion to anywhere from 1.2 billion
to 7.8 billion by 2150. The low figure assumes women in Africa will have only 1.7 children
in their lifetimes (the same as France's current TFR) and the high figure assumes they
will have 2.5 children (the same as Brazil's current TFR).
The mathematics of population projections demonstrate that the outcome of the
"population explosion" is very much in doubt.
© 1998 Population Reference Bureau, Inc
See also: The
People Bomb
