Page 153 - ABCTE Study Guide_Neat

connected to how many humans live on the planet. The graph below is a projection by the US Census
Bureau; it tracks and predicts world human population growth.

Migration and Distribution

Migration refers to large-scale movement of human populations; migration can have many causes,
including wars, famine, or a shift in climate. For example, the climate change in northern Africa birthed the
Sahara Desert, which caused people to move east to the fertile Nile Valley. If it had not been for this
dramatic change, the early civilizations of the Nile might have taken a radically different shape. A less
extreme example would be groups of people that move due to the seasons or due to agriculture.

Birth Rate

This figure is usually based on the number of live births per one thousand people. The countries with the
highest birth rate include Niger, Afghanistan, and Mali. Economic and political factors affect birth rates
around the globe; for example, in highly developed regions like Europe, having a large family is now an
economic liability, so the birth rate slows. Or consider China, where the political forces in that country
have slowed the birth rate to .87%.