Environmental Engineering Reference
Changes in the Environment
The spread of economic development has pushed the use of
automobiles to all parts of the modern world. The bulk of industrialized
nations including Japan, Britain, Germany, France and others have seen
great increases in energy use. At the end of the 20th century, the U. S. used
more energy per capita than any other nation, twice the rate of Sweden
and almost three times that of Japan or Italy. In 1988, the United States,
with only 5% of the earth's population, consumed 25% of all the world's
oil and released about a fourth of the world's atmospheric carbon.
When the earth was formed about 4.5 billion years ago, 95% of
the atmosphere consisted of carbon dioxide. The emergence of plant
life changed the atmosphere since plants, through the process of
photosynthesis, absorb carbon dioxide. Carbon from the atmosphere
was absorbed into the vegetation and when the vegetable matter died, it
decomposed, and formed coal and oil. This dropped the carbon dioxide in
the atmosphere to less than 1%.
Industrialization and the burning of fossil fuels reverses this process.
Instead of being absorbed out of the air, carbon is extracted from the
ground and sent into the atmosphere.
A major surge in U.S. energy consumption occurred between 1930
and the 1970, rising by 350% as more oil and natural gas was used for
industrial, agricultural, transportation and housing needs. Oil and natural
gas contain less carbon than coal or wood, but the demand for energy soared
as the nation's economy grew and consumers became more affluent. By
1950, Americans drove three-quarters of all the world's automobiles and
they lived in larger energy consuming homes with relatively inefficient
heating and cooling systems. Appliances were also increasing which
boosted power needs. Energy consumption slowed in the 1970s and 1980s,
as manufacturers designed more efficient appliances.
Private cars began to command American transportation and more
roads were needed. In the early 1930s, the National Highway Users