Environmental Engineering Reference
In-Depth Information
been seen as a national problem to be solved within the constraints of national economies. How-
ever, global climate change is clearly a global environmental problem requiring the coordinated
action of many nations over long time periods, on the order of a century. The regulatory regime
used by a nation to cope with environmental degradation within its borders does not exist in the
international community. Therefore, it will be necessary to seek multilateral international agree-
ments for GHG emission control by the major emitting nations if this growing problem is to be
ameliorated.
Any effective program for limiting the amount of climate change to be experienced in the
twenty-first and subsequent centuries must necessarily have significant impacts on the supply and
consumption of energy by nations and on their economies. The magnitude and comprehensiveness
of the needed adjustments to the energy economy will be much greater than what has been required
for dealing with urban and regional pollution. The first steps toward seeking international agreement
for climate change control were taken in the 1990s. These included seeking an international scientific
consensus on the understanding of climate change and the prospective effects of remedial measures,
along with a plan for allocation of national annual emission caps to be implemented within the first
two decades of the twenty-first century. This consensus resulted in the Kyoto protocol of 1997,
which aims to reduce annual global GHG emissions by an average of 5.5% below 1990 levels.
However, as of the year 2000, none of the industrialized nations has ratified the Kyoto protocol.
Nevertheless, individual countries are assessing (a) the measures they may need to secure some
degree of control over their respective national GHG emissions and (b) the policies and procedures
that will best meet their national objectives in dealing with climate change.
The emissions of non-CO
2
greenhouse gases can be reduced without resource to heroic mea-
sures. Anthropogenic methane emissions can be relatively easily reduced by preventing leakage
of the gas from gas wells, pipes, tanks, tankers, coal mines, and landfills. However, nitrous oxide
emission control is mired in uncertainty because we do not fully understand the sources of emis-
sion of this gas. The manufacture of CFC is being phased out worldwide as a consequence of an
international treaty, the Montreal Convention of 1987. Unfortunately, because of their very long
lifetimes in the atmosphere, CFC will contribute to global warming for many decades to come.
The reduction of emissions of carbon dioxide is a problem of a different kind and magnitude
than reducing emissions of the other GHG pollutants. Eighty-eight percent of the world's primary
energy sources and 63% of electricity generation comes from fossil fuels. Reducing CO
2
emissions
to the atmosphere simply means lowering the rate of consumption of fossil fuels. Burning less fossil
fuels or replacing them by other energy sources would involve a radical change in our energy supply
structure. Traditionally, population and economic growth was always associated with increase of
fossil fuel usage, not the inverse. Providing a burgeoning world population with energy and bridging
the energy consumption inequalities that now exist between developed and less developed nations
would normally require more fossil energy consumption, not less. There are no clear-cut solutions
to this dilemma.
In this topic we described some of the alternatives to increased fossil fuel consumption, such as
replacing fossil-fueled electricity production by nuclear and renewable sources, energy efficiency
improvements in fossil fuel usage, and sequestration methods for carbon dioxide. Most of these
alternatives require much greater capital investments and/or higher prices for commodities (includ-
ing electricity), that use primary energy for their production. These measures imply great changes
in how energy is supplied and utilized and will undoubtedly require government intervention in
the energy marketplace.
