Population - Environmental Science - page 66

The human population is unique compared to other species due to our ability to alter our environment effect-
ively and efficiently with the use of technology and invention. Although population growth has begun to stabil-
ize or decline in some countries, it continues to soar in others. Overall, the human population continues to
grow exponentially, and since we can alter our environment to suit our needs, we have extended the carrying
capacity of our planet for ourselves, while reducing the carrying capacity for other species.
Human Population Dynamics
Historical Considerations
Through most of human history, the Earth was not overpopulated and held only a few million people at any
given time. As humans became more advanced and began to invent more efficient ways of doing day-to-day
tasks and a safer way of life evolved, the population gradually and steadily increased. Two key events are re-
sponsible for this change:
• The Agricultural Revolution began about 10,000 years ago, and people started to grow crops and raise
livestock. This meant that a nomadic lifestyle was no longer necessary, and it was easier to get essential
nutrients to survive. People began to have more children and live longer lives.
• In the 1700s, the Industrial Revolution began. Life started to become more urban. Most people lived in
and near cities, sanitation and medical care improved, and manufacturing became prevalent. The use of
fossil fuels as an energy source sparked this new way of life and made it possible for manufacturing,
production, and transportation to be more efficient. Improvements in sanitation and healthcare increased
longevity, so people were living longer as well.
Currently, there are more than 6.9 billion people living on Earth, and the number is still growing exponentially.
Since 1967, the human population has doubled, with over 80 million people being added every year.
Distribution
Population growth is not the same in every country or every region. Currently, growth is slowing in developed
nations, while many developing countries are still growing at an astounding rate.
Studying the statistical change in human populations and applying the concepts of population ecology to this is
called demography. By studying the size, density, distribution, sex ratios, age structure, birth and death rates,
and movement of people, a demographer can help to predict shifts in populations and potential environmental
consequences throughout the world.
The distribution of the human population is considered to be clumped, with more people living in regions with
climates that are tropical, subtropical, or temperate. Such locations include China, India, Europe, and Mexico.
Populations are also the densest near water, whether freshwater or saltwater. More people living in a particular
area means there is more of an impact on the environment from use and pollution in that area.
Today, China has the world's largest population, with about 1.3 billion people; India is close behind, with 1.15
billion people; and the United States comes in third with about 300 million people. China and India still are
considered developing nations but are quickly catching up to developed countries due to increased job growth
and opportunities. The environmental impact of both countries is already large, but with more and more people
having the means to consume and the desire to live lifestyles based on consumerism, the effect on the environ-
ment will be even more dramatic and humans will move even closer to reaching carrying capacity on the plan-
et.