Environmental Engineering Reference
In-Depth Information
backed up by efficient harvesting and replanting
schemes. Clearly this is impossible, and current
estimates based on moderate cost-effectiveness
suggest that no more than 4-5 per cent of total
carbon emissions could be sequestered in this way
(Green 1992).
Together, these schemes—improved energy
efficiency, carbon taxation and afforestation—
would indeed lessen the impact of fossil fuels on
the environment, but no major improvement is
likely until society's dependence on carbonbased
fuels is much reduced. Alternative sources such
as the sun, the wind, the sea and the biosphere,
cannot supply energy in the amounts and at the
rate demanded. The other potential alternative—
nuclear fission—has been so discredited by recent
events that it cannot be given serious
consideration until problems of operational
safety and radioactive waste disposal have been
resolved. Thus, although developments in the
energy sector have the potential to ameliorate a
number of existing global environmental issues,
major improvements are unlikely under current
technological, socio-economic and political
conditions.
It is increasingly apparent that solutions to
the global environmental problems presently
facing society must be economically, socially and
politically acceptable. They must be more.
Current global problems are multifaceted,
therefore the solutions must be multifaceted.
They must consider societal and environmental
consequences equally, rather than emphasizing
the former, as is commonly done at present.
The environment suffers because of the time
scales followed by modern society. Politicians,
for example, tend to deal in short-term causes,
effects and solutions, living as they do from
election to election. Many environmental
problems do not fit readily into such a
framework. Rapid, sometimes catastrophic
change is an element in the environment, but,
more often than not, change is accomplished
through the cumulative effects of relatively minor
variations over a long period of time. As a result,
potentially important changes may not be
recognized, or, if they are, they are ignored
because of their seeming insignificance. Even
when attempts are made to deal with such
changes, the results may only become apparent
after a considerable period of time. In the case of
ozone depletion, for example, it will take several
decades following the complete abolition of CFCs
before ozone levels return to their normal range.
In politics, where immediate and obvious
solutions tend to be the order of the day, such a
time lag is often considered politically
unacceptable, and no action is taken.
Despite this, concern for environmental
change has been growing among politicians and
government bodies. They have made funds
available for the investigation of global
problems, and encouraged the dissemination of
the research results through conferences and
publications. The next stage in the process must
be the implementation of the recommendations
contained in the research reports. That is
proving to be difficult, however, since it requires
a long-range planning strategy, and modern
planning policy is designed to provide solutions
to short-term problems. Environmental impact
procedures, for example, seek to integrate the
environmental and socio-economic
considerations arising from the development of
a specific project and mitigate their effects at
the outset. It is assumed that the decisions made
at that time will minimize environmental
impact throughout the life of the project, but
there is already evidence that environmental
change is accelerating so rapidly that this
approach is now inappropriate. Current
environmental problems require long-range
planning extending several decades into the
future, and responsive to change, if they are to
be solved. Planners and policy-makers have not
yet adjusted to that requirement. For example,
reforestation is going ahead on the assumption
that current climatic conditions will prevail
during the life-span of the trees, yet in the next
50 years the intensification of the greenhouse
effect is likely to cause climate to change in the
areas being planted. Irrigation projects and
hydro-electric schemes costing millions of
dollars are being developed with no thought to
