Page 192 - Encyclopedia Of World History Vol IV

population growth as engine of history 1493

of innovation have allowed humans to produce the food tion. Such migration, in its turn, has been one of the
and resources needed to support rapid population major causes of the spread of agricultural communities
growth. Death rates fell in many parts of the world in the throughout the world. The rough calculations of Rein
last two centuries, partly because of the spread of new Taagepera suggest that the area of the inhabited earth
crops and improved knowledge about basic sanitation. within agrarian civilizations (a very rough measure of the
In the twentieth century, scientific medicine, and the area dominated by farming) grew from 0.2 percent some
introduction of antibiotics, have reduced death rates five thousand years ago to about 13 percent two thou-
throughout the world. But despite such advances, popu- sand years ago, and perhaps 33 percent just three hun-
lations could not have continued to rise if it had not been dred years ago (Christian 2004, 305).While population
for the burst of innovation we associate with the indus- growth was often the primary trigger for migrations of
trial revolution, which provided the energy, the resources, farmers into new regions, states often backed such migra-
and the techniques needed to feed, clothe, and supply the tions because their own fortunes depended on the size of
rapidly increasing populations of the modern era. Some the tax-paying populations under their control. State-
of the most important new technologies included im- backed migrations of this kind have been particularly
proved forms of irrigation, the introduction of artificial spectacular in recent centuries as imperial states such as
fertilizers and pesticides, the use of fossil fuels in agricul- Russia, China, Spain, and Great Britain backed migra-
ture, and the breeding of new and more productive vari- tions of farmers into previously unfarmed lands in
eties of major food crops such as rice and maize. Equally Siberia, Asia, the Americas, and Australasia.
important was the huge increase in available energy sup- Population growth has been one of the main drivers of
plies made possible by the fossil fuels revolution. increasing social complexity. There is little evidence for
Today, we may be in the middle of a new transition, significant increases in the size or complexity of human
often referred to as the “demographic transition.” Evi- communities until very late in the Paleolithic era. But
dence has been accumulating, in some regions for more human societies began to change significantly as soon as
than a century or two, that as death rates fall and population densities started to rise with the appearance
humans become more affluent, more urbanized, and bet- of agriculture. Larger, denser communities could no
ter educated, they have fewer children. By 2000, there longer be organized through the informal kinship struc-
was no net population growth in more than thirty of the tures that worked well enough in foraging communities,
world’s more affluent countries. This trend seems to most of which consisted of just a handful of people.
mark a return to a regime of systematic population lim- Once hundreds or even thousands of people began to
itation, like that of the Paleolithic era. live together in villages and towns, new types of social
coordination became necessary to limit conflict, organize
Population Growth worship, and organize collective activities such as
as a Historical Force defense, or the maintenance of irrigation systems. Even-
Although population growth has been a consequence of tually larger communities, supported by more productive
innovation, it has also shaped human history in profound technologies, allowed for the beginnings of specializa-
ways.The size and density of populations can have a pro- tion. No longer was everyone a farmer; so specialists had
found effect on rates of innovation, as well as on the struc- to buy their food and other necessities through markets,
ture of society, the power of states, the spread of disease, which had to be regulated and protected. Cities required
the health of commerce, and the availability of labor.The even more sophisticated forms of coordination to man-
following are some of the major types of change in which age refuse collection and maintain water quality, and for
population growth plays a significant role. defense.The earliest states appeared, in part, to take over
We have seen already that population growth can the new organizational tasks that emerged within dense
stimulate migration by causing localized overpopula- communities; but their power also reflected the large