Meghan McDonald McDonald 1 Mr.Hrkal OAC World Issues December 18th, 2000
Global Warming Now, for the first time in Earth's history, humans may be a
decisive factor in future climate change. The actions we make towards the
temperature of the earth and the depletion of the ozone layer are irreversible.
A warmer future could result from present-day human activities releasing large
amounts of heat-trapping gases into the air. These greenhouse gases are part of
the reason for the 1°F (.5°C) rise in global average temperature documented over
the past 100 years. If the Earth's temperature continues to rise as predicted,
future global warming could happen faster than any climate change of the last
10,000 years. If so, future variations in local climate could be even more
disruptive than those of the past. Fossil fuels, which release carbon dioxide
when burned, are used to generate electricity; heat and light homes and
workplaces; power factories and run cars. Unless we reduce population growth and
use of fossil fuels, the level of carbon dioxide in the atmosphere will double
by sometime in the middle of the next century. The future of Earth's climate may
depend partly on the buildup of heat-trapping gases, primarily carbon dioxide,
methane, and nitrous oxide, in the atmosphere. Industrialized nations now
release the most carbon dioxide. But how can this world wide disaster be
stopped? To fully understand the magnitude of this problem, we must look at the
causes McDonald 2 of global warming, what is being done to stop the problem,
consequences of this issue, and how we can prevent it. What is Global Warming?
The depletion of the ozone layer and global warming are a result of the heat
trapping abilities of “greenhouse gases”. The glass panels of a greenhouse and
the Earth’s atmosphere are both transparent to sunlight, and both trap heat.
Energy from the sun drives the earth’s weather and climate, and heats the
earth’s surface; in turn, the earth radiates energy back into space.
Atmospheric greenhouse gases trap some of the outgoing energy,
retaining heat somewhat like the glass panels of a greenhouse. Thus creating the
greenhouse effect. At present, the Earth appears to be facing a rapid warming,
which most scientists believe results, at least in part, from human activities.
The chief cause of this warming is thought to be the burning of fossil fuels,
such as coal, oil, and natural gas, which releases into the atmosphere carbon
dioxide and other substances known as greenhouse gases. As the atmosphere
becomes richer in these gases, it becomes a better insulator, retaining more of
the heat provided to the planet by the Sun. Through years of abuse and neglect,
the situation continues to worsen. Some may feel that Global warming is
inevitable, and that the climate will change no matter what. This is partly
true. Climate does change all the time, but it changes slowly. We are doing it
at enormous speeds, 60 times faster than normal. McDonald 3 Greenhouse Gases All
life on Earth relies on the greenhouse effect, without it, the planet would be
colder by about 33-Celsius degrees, and ice would cover Earth from pole to pole.
However, a growing excess of greenhouse gases in Earth's atmosphere threatens to
head in the other direction, toward continual warming. Carbon dioxide is the
most abundant greenhouse gas followed by methane and nitrous oxide.
Carbon dioxide flows into the atmosphere from many natural processes, such as
volcanic eruptions; the respiration of animals, which breathe in oxygen and
exhale carbon dioxide; and the burning or decay of organic matter, such as
plants. Humans escalate the amount of carbon dioxide released to the atmosphere
when they burn fossil fuels, solid wastes, and wood products to heat buildings,
drive vehicles, and generate electricity. At the same time, the number of trees
available to absorb carbon dioxide through photosynthesis has been greatly
reduced by deforestation, the long-term destruction of forests by indiscriminate
cutting of trees for lumber or to clear land for agricultural activities.
Methane is an even more effective insulator, trapping over 21 times more heat
than does the same amount of carbon dioxide. Methane is emitted during the
production and transport of coal, natural gas, and oil. Methane also comes from
rotting organic waste in landfills, and it is released from certain animals,
especially cows, as a byproduct of digestion. Nitrous oxide is a powerful
insulating gas released primarily by burning fossil fuels and by plowing farm
soils.
