Environmental Engineering Reference
In-Depth Information
Reducing unwanted pregnancies by strengthening family planning programs
could reduce the population from 10.2 to 8.3 billion by the year 2100. Reducing the
demand for large families through investments in human development could lead
to a further reduction from 8.3 to 7.3 billion in the year 2100.
The population momentum could be slowed if the average childbearing age of
women was raised. By increasing the average age of childbearing by 5 years, we
could achieve a further reduction from 7.3 to 6.1 billion by the year 2100. All such
reductions are theoretical upper limits of what could be achieved, but they highlight
the possible actions that could bring about a real reduction in population growth in
the next century.
As is well known, the developed countries have experienced demographic trans-
itions that have led to the total fertility rate (TFR) falling to approximately two,
which is the replacement rate. The precise causes for the decline of TFR are very
complex and synergetic in nature, including those listed above. The developing
countries can be expected to follow a similar trend.
The growth in energy consumption is linked to the development of cities; in the
past, primitive agricultural societies used modest amounts of energy per capita for
food, home, commerce, and industrial agriculture. Energy was mainly obtained
through the use of domestic animals and slaves. As urban life developed, the in-
