2.3 Trends in human population growth  (Page 4/10)

Current population trends

As mentioned earlier, the earth’s population is seven billion. That number might not seem particularly jarring on its own; after all, we all know there are lots of people around. But consider the fact that human population grew very slowly for most of our existence, then doubled in the span of half a century to reach six billion in 1999. And now, just over ten years later, we have added another billion. A look at the graph of projected population indicates that growth is not only going to continue, but it will continue at a rapid rate.

The United Nations Population Fund (2008) categorizes nations as high fertility, intermediate fertility, or low fertility. They anticipate the population growth to triple between 2011 and 2100 in high-fertility countries, which are currently concentrated in sub-Saharan Africa. For countries with intermediate fertility rates (the U.S., India, and Mexico all fall into this category), growth is expected to be about 26 percent. And low-fertility countries like China, Australia, and most of Europe will actually see population declines of approximately 20 percent. The graphs below illustrate this trend.

Projected population in africa

Projected population in the united states

Projected population in europe

It would be impossible to discuss population growth and trends without addressing access to family planning resources and birth control. As the stages of population growth indicate, more industrialized countries see birthrates decline as families limit the number of children they have. Today, many people—over 200 million—still lack access to safe family planning, according to USAID (2010). By their report, this need is growing, with demand projected to increase by 40 percent in the next 15 years. Many social scholars would assert that until women are able to have only the children they want and can care for, the poorest countries will always bear the worst burden of overpopulation.

Further research

To learn more about population concerns, from the new-era ZPG advocates to the United Nations reports, check out these links: (External Link) and (External Link)

Long-term consequences of exponential human population growth

Many dire predictions have been made about the world’s population leading to a major crisis called the “population explosion.” In the 1968 book The Population Bomb , biologist Dr. Paul R. Ehrlich wrote, “The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.” ^{Paul R. Erlich, prologue to The Population Bomb , (1968; repr., New York: Ballantine, 1970).} While many critics view this statement as an exaggeration, the laws of exponential population growth are still in effect, and unchecked human population growth cannot continue indefinitely.

Efforts to control population growth led to the one-child policy    in China, which used to include more severe consequences, but now imposes fines on urban couples who have more than one child. Due to the fact that some couples wish to have a male heir, many Chinese couples continue to have more than one child. The policy itself, its social impacts, and the effectiveness of limiting overall population growth are controversial. In spite of population control policies, the human population continues to grow. At some point the food supply may run out because of the subsequent need to produce more and more food to feed our population. The United Nations estimates that future world population growth may vary from 6 billion (a decrease) to 16 billion people by the year 2100. There is no way to know whether human population growth will moderate to the point where the crisis described by Dr. Ehrlich will be averted.

Another result of population growth is the endangerment of the natural environment. Many countries have attempted to reduce the human impact on climate change by reducing their emission of the greenhouse gas carbon dioxide. However, these treaties have not been ratified by every country, and many underdeveloped countries trying to improve their economic condition may be less likely to agree with such provisions if it means slower economic development. Furthermore, the role of human activity in causing climate change has become a hotly debated socio-political issue in some developed countries, including the United States. Thus, we enter the future with considerable uncertainty about our ability to curb human population growth and protect our environment.

Section summary

The world’s human population is growing at an exponential rate. Humans have increased the world’s carrying capacity through migration, agriculture, medical advances, and communication. The age structure of a population allows us to predict population growth. Unchecked human population growth could have dire long-term effects on our environment.

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