Since the early 1800’s, the human population on Earth has been growing exponentially. The primary cause for the dramatic growth had little to do with an increase in birth rate. The main cause was a decrease in the death rate. Thanks to improved medicine, agriculture, and living conditions, people have begun to live longer and healthier lives. This also means that they produce more children that are more likely to survive to adulthood and produce even more children. Though it took over 10,000 years for human population to increase to 1 billion people, it took a little over a century to reach 2 billion and a mere 30 years to reach 3 billion.
Of course one of our main concerns is the carrying capacity of the Earth. Simply put, can the Earth sustain so many people? Unfortunately, we don’t know. Humans already have a tremendous impact on the environment and many countries, the United States in particular, are a great drain on resources. The rapidly growing human population will be a topic of great international debate and concern over the next 20 years.
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2002 McGraw-Hill Higher Education