Geography Reference
In-Depth Information
But why are the rates dropping and the gap widening? Basically, birth rates drop because of a tem-
pering of the last bulleted items of Stage 1, but death rates are declining much faster because of the
following:
Basic and widespread improvement in water supply and sanitation are having a very posit-
ive effect on public health.
Medicines and vaccines are becoming accessible to more and more people.
Infant mortality is dropping and life expectancy is rising. More people are reaching repro-
ductive age and are reproducing. People are living longer in their reproductive years and are
reproducing more.
Death rates are dropping faster than birth rates, so population grows — slowly at first, and
more dramatically more recently.
The widening gap between birth rates and death rates results in growing rates of natural increase.
Thus, looking again at the global map of natural increase (see Figure 11-4), most countries in the
“high” category are in the early expanding stage.
Stage 3: Late expanding
Birth rates exceed death rates by a narrowing margin in this stage (see Figure 11-5). When that
happens, population grows but at rates that are progressively slowing. Look once at Figure
11-3 and its S-shaped curve of population growth. The conditions just described correspond
to the top — that is,
late
— half of the curve, when population was
expanding
at slower and
slower rates after years of skyrocketing. Hence the name of this stage is
late expanding.
Be-
cause birth rates exceed death rates by a
decreasing
margin, the result is a lowering of the
rate of natural increase. On the map of natural increase (see Figure 11-4), most countries in
the “medium” category are experiencing this stage and its attendant social conditions, which
include the following:
Improvements continue to be made in public health, resulting in lower infant mortality and
longer life spans. Thus, the death rate continues to decline.
As the economy develops, machines perform increasing amounts of work that used to be
done manually. Thus, the incentive to produce children strictly for their labor potential drops.
