Lecture 6: Modern demographics
The next two lectures will concern modern demographics and migration in the era of
globalization. This lecture will be about modern birth and death rates and population growth, and
the next lecture will be about the history of migration, migration economics and policy
considerations. It may seem odd to start with modern demography and then revert to the history
next time, but the reason is that I need the demographic theory to help explain the history.
As we’ll see, these two lectures are related to each other in other than theoretical ways.
Modern demographics began with the transition from traditional to modern society, which we
described in the first lecture, and in fact the T to M transition is the driving force behind all
aspects of modern demographics; if you joined the class late, you may want to review the Lecture
1 notes in the Globalgroup. At the same time, we can understand migration for the past 150 or so
years as part of globalization, the final phase of the T to M transition, most obviously because the
transportation revolution of the nineteenth century was the basic precondition for mass migration,
and also because globalization created economic opportunities that motivated large-scale
migrations. Finally, there are direct connections between modern demographics and modern
migration; for example, the falling birth rates and contracting populations create economic
problems that immigration, perhaps, can solve.
The conventional wisdom concerning population is rapidly being revised. Forty years
ago, it was believed that world population was expanding at unprecedented rates and would
continue to do so until the human race ran out of food, clean water or some other necessary
resource, leading to massive famines and possibly to a social collapse.
This picture was half right. The population was expanding at rates never experienced
before, rates that would cause the population of the world to double between 1960 and 1999,
from three billion to six billion. However, this pattern did not continue. In the past few years,
there has arisen another phenomenon, completely different from the first but also completely
unprecedented: in half the countries of the world, birth rates have fallen so low that the number
of births are no longer sufficient to replace the existing population, which will therefore not
merely not continue to increase but instead will fall. There is no earlier period in history during
which the population fell, not because of famine or disease, but simply because babies were not