Geoscience Reference
In-Depth Information
densely populated and produce prodigious amounts of garbage.
Some of this trash, unfortunately, winds up in the ocean and
circulates around the basin in the gyre before it washes up
on shore (Figure 20.3b). The amount of trash in the northern
Pacific is now so high that the area has been referred to as the
North Pacific garbage patch
. To make matters worse, a huge
amount of debris wound up in the northern Pacific following the
recent Japanese tsunami discussed in Chapter 13. Most of this
trash is plastic, some of which is being consumed by a variety
of animals with harmful (and even fatal) results (Figure 20.3c).
Countless examples of this kind of impact are occurring around
Earth at the present time and will continue into the future.
The environmental impacts of a growing population are
enormous. Some parts of the world have industrialized and
reached relatively stable population levels, but others are in the
process of developing economically and are rapidly growing.
An example of an industrialized (or “developed”) country is the
United States, which has long been a global leader in techno-
logical innovation. As a result, the quality of life for the vast
majority of Americans is generally high, certainly at least with
respect to most other countries. Developing countries such as
India and China, in contrast, are in the process of industrial-
izing, which means that large numbers of people are reaching
the middle class for the first time and thus now have the income
to purchase consumer goods. Still other countries, such as a
number in Africa, have just begun to develop economically and
are populated mostly by people living on less than $1 per day.
Many people in these countries live at a level of poverty that the
average American simply cannot imagine.
The distinction between the developed and developing
countries is important because their population growth rates are
very different. Population in the industrialized world reached
about 1 billion in 2000 and has essentially stabilized since that
time (Figure 20.4). Future projections suggest that it may even
slowly decrease for the next century due to lower birth rates.
In stark contrast, population in the developing world began to
grow rapidly in the late 20th century when technological and
health advances reached those areas. Leading the way have
been China and India, which now each contain more than 1 bil-
lion people. According to current projections, population in
the developing world will continue to increase rapidly for the
foreseeable future, with perhaps 7 billion people in these areas
by 2050.
The rapid population growth rates in the developing world
are very important as far as sustainable development and en-
vironmental change are concerned. For one thing, increased
population pressure in regions with a moderate climate means
that more people will move out of those places into marginal ar-
eas with limited carrying capacity, such as the African Sahel or
the Middle East. As far as future climate change is concerned,
the Intergovernmental Panel on Climate Change (IPCC) be-
lieves that the combination of increasing population and rapid
economic growth in the developing world makes further tem-
perature increases more likely because this growth will largely
depend on fossil fuels that produce greenhouse gases. For ex-
ample, to meet the rapidly increasing demand for energy in the
growing Chinese economy, the government there is in the midst
of building 160 new coal power plants in the next four years.
In a similar vein, an Indian auto maker is now producing an
automobile for the country's growing middle class that sells for
less than $3000. Although this car is highly efficient (>40 mi/gal
or mpg), its development and potential high sales make in-
creased greenhouse gas production a certainty because tens of
thousands of Indians will now own a car for the very first time.
These issues of economic development, growing hu-
man population, and environmental impacts are happening all
around the world. In dealing with current and future environ-
mental concerns, an understanding of physical geography is
important to identify, manage, and, where possible, solve issues
associated with sustainable development. The remainder of this
chapter presents four case studies that examine the impact that
humans have on the environment in a particular place, and vice
versa. As you read about them, be sure to notice how these is-
sues are distinctly related to physical geography and look for
the topics that were covered in earlier chapters.
World Population Growth, 1750-2150
Population (in billions)
KEY CONCEPTS TO REMEMBER ABOUT
HUMAN POPULATION
Less developed countries
10
8
1.
Carrying capacity refers to the number of individuals
who can be supported within a landscape in a way that
does not degrade the natural, social, cultural, and eco-
nomic environment beyond sustainable limits.
6
More developed countries
4
2
2.
The onset of the Holocene Epoch is an important time
marker in the development of human societies because
the climate began warming, making life easier.
0
1750 1800 1850 1900 1950 2000 2050 2100 2150
Figure 20.4 World population growth in the industrialized and
nonindustrialized world from 1750 to 2100.
Note the rapid
growth in the developing world that is currently taking place,
whereas population in the developed world has been stable for
some time. (
Source
: The United Nations.)
3.
The development of agriculture about 8000 years ago
set the stage for later population growth because it
raised the carrying capacity of landscapes and allowed
more people to live in smaller geographical areas.
