predict that by around 2040, global TFR will be 2.1, which represents the replace-
ment rate for the existing population, or “zero population growth.”
As of 2010, there are almost 7 billion people onEarth. This total is larger than at
any other time in history, and each day brings a new global record for human popu-
lation, since our numbers continue to increase, although the rate of increase, as
shown above, is slowing. There are, however, some rather stark regional differences
in population dynamics. Although the TFR for the developed world is now below
the replacement value of 2.1, the TFR for the developing world currently
approaches 4, meaning that virtually all current population growth is occurring in
the developing countries. It is highly probable that this trend will continue for at
least another generation. TheInfant Mortality Rate(IMR) is also much lower
among developed countries than in Africa, South Asia, and other lesser developed
regions. The IMR for a country is calculated by counting the deaths of all infants
in the first year of life in a given year, divided by every 1,000 live births. This figure
again is reported as a decimal number. Infant Mortality Rates today range from 2 to 3
for Japan and some European countries, to above 100 for many countries in Africa.
The IMR is not only useful for understanding various aspects of population struc-
ture and growth, but also serves as a general comparative measure of quality of life.
For the most part, the IMR has been declining along with the general mortality rate
in the developing world for the past 50 years, and this has resulted in continued
expansion of the population despite a drop in birth rates in many regions.
The scientific study of population and the forces behind how it changes was ini-
tiated by Thomas Malthus at the end of the 1700s, and population growth has been
a controversial subject ever since. Malthus developed hisMalthusian Theory
regarding the dynamics of human population growth, which suggested that
humans reproduce in such a manner as to induce a recurring cycle of “feast and
famine” in which periods of adequate food supplies are alternated with periods
of shortages, because of a natural inclination for humans to over reproduce and
exceed their ability to produce food. Offered at the beginning of theagricultural
revolution, Malthusian theory has to date appeared to have little validity, but in
the 1960s the neo-Malthusian school revised the theory, arguing that in fact the
longer term trends in human population growth did follow the pattern described
by Malthus. Most of the predictions of this school also have failed to come to fru-
ition, but the basic question regarding how many people the planet can support has
not been answered. Some scholars and policymakers hold that the “human family”
has already reached its optimum size, and that only the approach ofsustainable
developmentwill ensure that humanity will continue to have access to sufficient
natural resourcesand food and maintain a reasonable quality of life for the great
majority of people. Others believe that the planet has the capacity, and human
beings the ability, to maintain a much larger population than even the nearly
Population 261