Migration from rural to urban areas is largely a result of a desire for greater access to sources of education, health care and improved job opportunities. In the early 1800s less than 3.5 percent of the world’s people were living in cities of 20,000 or more and less than 2 percent in cities of 100,000 or more today more than 40 percent of the world’s people are urbanites, and the trend is acceleration. Once in the city, perhaps three out of four migrants achieve some economic gains. The family income of a manual worker in urban Brazil, for example is almost five times that of a farm laborer in a rural area.
By 2030, estimates indicate that more than 61 percent of the world’s population will live in urban areas and at least 27 cities will have populations of 10 million or more, 23 of which will be in the less developed regions. Tokyo has already overtaken Mexico City as the largest city on Earth, with a population of 26 million, a jump of almost 8 million since 1990.
Although migrants experience some relative improvement in their living standards, intense urban growth without investment in services eventually leads to serious problems. Slums populated with unskilled workers living hand to mouth put excessive pressure on sanitation system, water supplies and other social services. At some points, the disadvantages of unregulated urban growth begin to outweigh the advantages for all concerned.
Consider the conditions that exist in Mexico City today. Besides smog, garbage and pollution brought about by the increased population, Mexico City faces a severe water shortage. Local water suppli0es are nearly exhausted and in some cases unhealthy. Water consumption from all sources is about 16,000 gallons per second, but the underground aquifers are producing only 2,640 gallons per second. Water comes for hundreds of miles away and has to be pumped up to an elevation of 7,444 feet to reach Mexico City. This is a grim picture of one of the most beautiful and sophisticated cities in Latin America. Such problems are not unique to Mexico; throughout the developing world, poor sanitation and inadequate water supplies are consequences of runaway population growth. An estimated 1.1 billion people are currently without access to clean drinking water and 2.8 billion have access to sanitation services. Estimates are that 40 percent of the world’s population 2.5 billion people will be without clean water if more is not invested in water resources. Prospects for improvements are not encouraging because most of the world’s urban growth will take place in the already economically strained developing countries.
Population Decline and Aging:
While the developing world faces a rapidly growing population, the industrialized world’s population is in decline and rapidly aging. Birthrates in Western Europe and Japan have been decreasing since the early or mid 1960s more women are closing are choosing careers instead of children, and many working couples are electing o remain childless. As a result of these and other contemporary factors, population growth in many countries has dropped below the rate necessary to maintain present levels. Just to keep the population from falling a nation needs a fertility rate of about 2.1 children per woman. Not one major country has sufficient internal population growth to maintain itself, and this trend is expected to continue for the next 50 years. Europe’s population could decline by as much as 88 million (from 375 million to 287 million) people if present tr6ends continue to 2015.
At the same time that population growth is declining in the industrialized world, there are more aging people, today than ever before. Global life expectancy has grown more in the last 50 years than over the previous 5,000 years. Until the industrial Revolution, no more than 2 or 3 percent of the total population was over the age of 65. Today in the developed world, the over age 65 group will amount to 14 percent and by 2030 this group will reach 25 percent in some 30 different countries.