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Human Population: Challenging the Balance
Jacques Cousteau, the famous explorer who opened the world's eyes to the wonder and splendor of our undersea world said it best: "Population growth is the primary source of environmental damage." Of course, this is not a comparison to natural catastrophes that eventually result in a natural change of life and ecosystems, but rather it is a statement about the challenges human population poses for nature. Yet, the human population challenge has really occurred only recently. Let's look at why. More people have been added to the Earth's population in the 20th century than at any other time in human history. In 1900, just 100 years ago, the world's human population numbered two billion people. Today, the total human population has grown three times as large and is now over six billion people. The rate of population growth has gone up rapidly in the past two centuries, from .0015% before 1800 to 1.2% today. At this rate, the Earth adds one billion more people every 14 years. If this continues, the world's population will double in the next century, nearing 12 billion in the year 2100. Our planet truly is becoming a more crowded place to live. What happened over the past 200 years to create such a rapid surge in the number of people living in the world? There are a few simple ideas that lie behind these trends.Before 1900, many children who were born did not reach adulthood so they never had their own children. In America and Europe, young children died of many diseases that we now immunize against such as diphtheria, tetanus, measles, pneumonia and whooping cough. In the 20th century, as these diseases became less common, more children lived to adulthood.The result was that more children than ever before were born and lived and had their own children, all of which increased the size of the world's population. And thus one predator ofhumans began to recede.
In the latter part of the 20th century, people in other parts of the world -- Africa, Asia, South America and the Middle East -- who had traditionally lost many children to disease, began to catch up with the developed world. People in these parts of the world began to adopt health practices such as immunizing children that also allowed more children to live. As these children grew to adulthood they too started their own families and this also has contributed to the world's current population growth. But here is the critical question: Will Earth's population continue to grow as fast as the last 100 years?
The United States will continue to grow. While birth rates in America have gone down -- primarily because of the migration of persons from other countries -- we will continue to have steady population growth. Today, the US has over 287 million people and is expected to grow to 400 million people by 2050.
The other issue is, even if people worldwide choose to have fewer children tomorrow, it will still take 50-60 years for the world's population to stabilize, as there are so many people currently in their childbearing years. Slowing the growth of the world's population, even though this is happening in many parts of the world, may not be happening quickly enough: The world's populations may still double again by the end of the this century to 12 billion persons. Is this too many people for the size and resources of the planet? Will our natural resources run out? Will natural habitat vanish? Will starvation increase? Will we all live in large cities? What are barriers to decreasing human population growth? And what are we doing and can we do to prevent overpopulation? We will explore these and other population issues in the next three parts of Human Population: Challenging the Balance here at ecology.com. (Mandy Shaivitz, MPH, UCLA, contributed to this article.) Did You Know?
Other Sources of InformationAbout the AuthorDr. Deborah Glik is a Professor, Community Health Sciences at the University of California at Los Angeles (UCLA) and serves as Director, UCLA Health and Media Research Group. |
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At the same time, people are also living longer. For example, in the U.S. the average life expectancy in 1950 was 57 years. Now people, on average, can expect to live 77 years. People living longer increase the population size, and this means that more people are living together on Earth at the same time.
There are signs that population growth rates in some parts of the world have started to slow down. In Europe, America, and in parts of Asia and Australia, most families are having less than two children. Some of these countries are actually experiencing negative population growth meaning that their populations are growing smaller. In Russia, Eastern Europe, Germany and Northern Europe populations may actually shrink in size because people are having fewer and fewer children.
However, there are many parts of the world where population growth is still very high and populations are expanding rapidly. Six countries account for one half of the population added every year: these are China, India, Pakistan, Bangladesh, Indonesia, and Nigeria. China alone has 1.3 billion people, and India has slightly over 1 billion people, or about one third of the total world population. In countries where the rate of natural increase is approximately 2%, their population will double ever 34 years. If population growth continues to be high in these and other countries, attempts to slow down the growth of the world human population in the twenty first century may well be futile.
