Environmental Engineering Reference
In-Depth Information
Third,
once pollutants become dispersed into the
environment at harmful levels, it usually costs too
much to reduce them to acceptable levels.
Pollution prevention (front-of-the-pipe) and pol-
lution cleanup (end-of-the-pipe) solutions are both
needed. Environmental scientists and some econo-
mists urge us to put more emphasis on prevention be-
cause it works better and is cheaper than cleanup.
1-5 ENVIRONMENTAL PROBLEMS:
CAUSES AND CONNECTIONS
Figure 1-8
Natural capital degradation:
point-source air pollution
from a pulp mill in New York State.
Key Environmental Problems and Their
Basic Causes
The major causes of environmental problems are
population growth, wasteful resource use, poverty,
poor environmental accounting, and ecological
ignorance.
We face a number of interconnected environmental
and resource problems (Figure 1-9). The first step in
dealing with these problems is to identify their under-
lying causes, listed in Figure 1-10 (p. 14).
cars and in the total distance each travels have re-
duced the effectiveness of this cleanup approach.
Second,
cleanup often removes a pollutant from
one part of the environment only to cause pollution in
another. For example, we can collect garbage, but the
garbage is then
burned
(perhaps causing air pollution
and leaving toxic ash that must be put somewhere),
dumped
into streams, lakes, and oceans (perhaps caus-
ing water pollution), or
buried
(perhaps causing soil
and groundwater pollution).
SOLAR
CAPITAL
EARTH
Goods and services
Heat
Human
Economic
and
Cultural
Systems
Human Capital
Depletion of nonrenewable resources
Degradation of renewable resources
Natural Capital
Pollution and waste
g
Figure 1-9
Natural capital use, depletion, and degradation:
human and natural capital pro-
duce an amazing array of goods and services for most of the world's people. But this rapid flow of
material resources through the world's economic systems depletes nonrenewable resources, de-
grades renewable resources, and adds heat, pollution, and waste to the environment.
