CHAPTER 31

Demographic and Environmental Developments

IN THIS CHAPTER

Summary: Although the Industrial Revolution generated overall improvements in living standards, it
also caused atmospheric pollution in industrialized cities. Environmental challenges of the twentieth
and twenty-first centuries included efforts to resolve poor environmental quality from industrial and
automobile emissions. Potential threats to the environment also resulted from oil spills, the
devastation of warfare, and the danger of meltdowns from nuclear plants.
Since 1914, warfare, famine, disease, and migration have affected global population distribution.
Most migrants moved from developing to developed nations in search of improved economic
opportunities.

Key Terms

Green Revolution
guest workers
ozone depletion
xenophobia

War Years

World War I resulted in the deaths of 10 million Europeans and eliminated nearly a generation of
young European men. The lack of potential husbands forced many European women to remain
unmarried. The drastic decline in marriages lowered the European birth rate and population growth
in future generations. Bombs and troop movements destroyed cities, factories, and agricultural land.
Another 35 million people lost their lives in World War II. Because of postwar boundary changes,
hundreds of thousands of displaced persons were forced to relocate.