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ESSAY SAMPLE ON "FOSSIL FUEL CONSUMPTION, CO2 AND ITS IMPACT ON GLOBAL CLIMATE" |
At the beginning of human history, we had to satisfy our energy needs (for food, heat and
movement) by using our own muscle power and gathering or hunting naturally available
plants, animals and wood. Each stage in the evolution of human society (the development
of farming, domestication of animals, harnessing of wind and water power) increased the
average per capita energy use, but it was the Industrial Revolution and the exploitation
of fossil fuels which marked the transformation of societies into the energy-intensive
economies of today.
Since the eighteenth century the industrialising countries have come to rely on
non-renewable energy resources, and at present about 80 per cent (Myers, 1994) of the
world's commercial energy is derived from oil, coal and gas. Although it has been
observed that the growth of energy consumption is closely correlated with the increases
in gross national product thus our economic development, the major sources of energy
(that is fossil fuels) are 'stock resources'. Fossil fuels are consumed by use and the
current consumption patterns are non-sustainable. It is recognised that energy
conservation and the development of renewable energy sources will be needed to sustain
economic growth.
The quantity of ultimately recoverable fossil fuels is limited by geology and remains a
matter of suspicion, but the view of the 1970s that scarcity was imminent is still
popular. It is the 1973 Oil Crisis marked the transition from abundant, low-cost energy
to an era of increasing prices and scarcity. Today concerns over scarcity have been
overtaken by the question of whether human beings can afford to meet the environmental
costs of continued fossil fuel consumption. One of the most widespread concern related to
global climatic changes.
Introduction:
Climate represents normal weather condition of an area over a period of many years. This
is in contrast to weather which is the day to day changes in the atmosphere. It is now
realised that our global "climatic normals" had fluctuated in the past millions of years
which was nowhere related to human activities. Nevertheless, with the increasing human
population and our reliance on fossil fuels since the last century, we have definitely
'participated' in the climatic changes which are taking place to a certain extent.
Since the Stockholm Conference in 1972, more and more attentions have been drawn to the
issue of global warming, which is the increase in global temperature caused by the
atmospheric greenhouse effect. We have greenhouse effect because some trace components of
our atmosphere re-absorb and retain certain wavelengths of heat radiated from the Earth's
surface, and the burning of fossil fuels have increased the tropospheric concentration of
all of these compounds, especially carbon dioxide # (CO2).
The Greenhouse Gas ? CO2: A Product of Fossil Fuel Consumption:
'Pollution' of the atmosphere from the consumption of fossil fuels has many effects.
Perhaps the best know are modifications that have led to changes in carbon dioxide.
In some ways carbon dioxide cannot be classified as an air pollutant as it is reasonably
abundant in the natural atmosphere (0.03%), and it is a basic product of all fossil fuel
consumption. Although the chemical reaction in combustion of fossil fuels is not always
simple, it can be summarised as the release of the carbon combined with atmospheric
oxygen atoms to form carbon dioxide. This process is often referred as respiration, such
that:
C6H12O6 + 6O2 + heat ? 6CO2 + 6H2O
Here, we see that carbon dioxide is not an impurity, as a matter of fact, life on the
earth is somehow depending on this gas, either directly through photosynthesis (plants)
or indirectly via the food-chain (animals). Nevertheless, this gas plays an important
role in the heat balance of the earth, because of its distinctive heat-storage
properties.
We often refer carbon dioxide as a 'greenhouse gas', as the name implies, it is a kind of
material that would absorb and retain heat. Carbon dioxide in the atmosphere is
transparent to the sun's short-wave radiation, which is primarily in the ultra-violent
and visible portions of the electromagnetic spectrum (l=0.1-1 mm). After the incident
radiation has penetrated the atmosphere and been absorbed by the earth's surface, the
earth re-radiates the thermal energy; however, because the earth's surface temperature is
relatively low, the wavelengths of the terrestrial radiation are now in the infrared
(l=4-20 mm). Carbon dioxide strongly absorbs radiation in the 7 to 14-mm wavelength
region, which overlaps with the peak of intensity of the outgoing radiation. The net
effect of the carbon dioxide in the atmosphere is to prevent some of the thermal energy
from escaping from the earth; hence, it leads to a heating of the atmosphere. In general,
the more carbon dioxide in the atmosphere, the more heat that will be trapped, and a
warmer atmosphere will result.
Change in Atmospheric Chemistry and Global Warming:
The burning of peat, coal, petroleum or natural gas (all carbonaceous materials)
virtually returns the atmospheric carbon that had been removed hundreds of million years
ago by trees and plants in their process of photosynthesis. Thus in a sudden, relatively
brief span of time, less than two centuries, the contemporary atmosphere has become
burdened with vast additional quantities of a strong infrared absorber, because of the
utilisation of fossil fuels in this period. It is believed that the level of carbon
dioxide has been increasing. Measurements of the CO2 concentration have been carried out
at an observatory on Mauna Loa, whose data is most quoted and most complete. Observations
show a steady rise in atmospheric carbon dioxide of about 1 ppm per year over the past
quarter of a century. At the South Pole station, the upward CO2 trend closely parallels
that at Mauna Loa (Kraushaar, 1988). Forecasts based on the current rate of fossil fuel
consumption suggest that by the year 2065 the CO2 concentration will increase from its
present value of 350 ppm to a value of 600 ppm. It has been estimated that the
pre-industrial level of carbon dioxide have been as low as 260-70 ppm by volume (Goudie,
1994). Thus, it appears that the industrial world is increasing the atmospheric CO2
contents by an appreciable amount.
It is arguable that the increase in CO2 concentration may not be induced by fossil fuel
consumption since the carbon cycle is always operating, it could be due largely to a
reduction of the biomass. However, Kraushaar and Ristinen suggested that the net biotic
pool of CO2 has not been modified sufficiently to account for the carbon dioxide
increase. They said that, "Although there has been cutting of forests, there has also
been intensive agriculture established by irrigation of land that was previously not very
productive." and the combustion of fossil fuels is that major source of the increase in
atmospheric CO2. Moreover, as the amount of fossil fuels consumed each year is
approximately known, the CO2 released can therefore be estimated. Together with the level
of CO2 concentration obtained in various stations in the earth, it is calculated that 52%
of the 14 billion tones of carbon dioxide is being retained in the atmosphere per year;
and 37% sinks into the oceans, whereas the depositional locations of the remaining 11%
remain mysterious at present (Kraushaar, 1988).
The next question comes with the effect of these carbon dioxide increases on global
climate and here is where the controversy lies. Vostok ice-core data suggest a close
correlation between CO2 levels and mean surface temperature over the past 160,000 years
(Benarde, 1992), but scientist still cannot figure out whether carbon dioxide leads
temperature shifts or temperature changes leads CO2 shifts. There may even be a third
factor provoke both CO2 and temperature changes. Moreover, the upward trend of the
contemporary global warming only lasts for 15 years (Tolba, 1992). There have been much
fluctuation on temperature before 1900. For example, in Europe, particularly low
temperature normals have been experienced during the period 1430 to 1850 A.D. Therefore,
'global warming' could just be another natural fluctuation in temperature. At present
time, using our current understanding on the atmosphere that based on hypothesises and
models, we cannot yet make accurate predictions on the future climate.
Conclusion:
Although there are still many problems regarding the relationship of carbon dioxide and
global climatic changes and even global warming itself, there is little question that
climate (temperature) and CO2 are inextricablely linked (from the ice-core studies) and
the temperature of the earth has been increasing over the last decade. More on that, it
is a fact that the burning of fossil fuels do release infrared-absorbing carbon dioxide
to our atmosphere. Therefore, it is just a logical conclusion that the greenhouse is
here, as it always does. It appears that there is excessive heating within the greenhouse
which is induced by our increasing rate of fossil fuel consumption, and the problems that
lies behind global climatic change are far reaching . Perhaps, the real limit to our
fossil fuel consumption will be the CO2 problem but not the size of the resource. A
Chinese proverb says that "prevention is better than cure." Approaches to energy
conservation could be the key.
Bibliography:
Benarde, M. A., 1992, Global Warning... Global Warming, John Wiley & Sons, Inc., 52-65.
Goudie, A., 1994, The Human Impact on the Natural Environment, Cambridge: The MIT Press,
301-7.
Kraushaar, J. J. & Ristinen, R. A., Energy and Problems of a Technical Society, John
Wiley & Sons, Inc., 394-400.
Myers, N., 1994, The Gaia Atlas of Planet Management, London: Gaia Books Limited,
96-113.
Tolba, M. K., 1992, The World Environment 1972-1992, London: Chapman & Hall, 61-71.
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