Environmental Engineering Reference
In-Depth Information
1
CHAPTER
Energy and the Environment
1.1
INTRODUCTION
Modern societies are characterized by a substantial consumption of fossil and nuclear fuels needed
to provide for the operation of the physical infrastructure upon which these societies depend: the
production of food and water, clothing, shelter, transportation, communication, and other essen-
tial human services. The amount of this energy use and its concentration in the urban areas of
industrialized nations has caused the environmental degradation of air-, water- and land-dependent
ecosystems on a local and regional scale, as well as adverse health effects in human populations.
Recent scientific studies have forecast potentially adverse global climate changes that would result
from the accumulation of gaseous emissions to the atmosphere, principally carbon dioxide from
energy related sources. This accumulation is aggravated by an expected expanding consumption
of energy both by industrialized nations and by developing nations seeking to improve the living
standards of their growing populations. The nations of the world, individually and collectively, are
undertaking to limit the damage to human health and natural ecosystems that attend these current
problems and to forestall the development of even more severe ones in the future. But because
the source of the problem, energy usage, is so intimately involved in nations' and the world's
economies, it will be difficult to ameliorate this environmental degradation without some adverse
effects on the social and economic circumstances of national populations.
To comprehend the magnitude of intensity of human use of energy in current nations, we might
compare it with the minimum energy needed to sustain an individual human life, that of the caloric
value of food needed for a healthy diet. In the United States, which is among the most intensive
users of energy, the average daily fossil fuel use per capita amounts to 56 times the necessary daily
food energy intake. On the other hand, in India, a developing nation, the energy used is only 3 times
the daily food calorie intake. U.S. nationals expend 20 times the energy used by Indian nationals,
and their per capita share of the national gross domestic product is 50 times greater. Evidently, the
economic well-being of populations is closely tied to their energy consumption.
When agricultural technology began to displace that of the hunter-gatherer societies about
10,000 years ago, activities other than acquiring food became possible. Eventually other sources
of mechanical energy—that of animals, wind, and water streams—were developed, augmenting
human labor and further enhancing both agricultural and nonagricultural pursuits. As world popula-
tion increased, the amount of crop and pasture land increased in proportion, permanently replacing
natural forest and grassland ecosystems by less diverse ones. Until the beginning of the industrial
revolution several centuries ago, this was the major environmental impact of human activities.
Today, we are approaching the limit of available land for agricultural purposes, and only more
intensive use of it can provide food for future increases of world population.
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