FREE ESSAY ON THE GREENHOUSE EFFECT

THE GREENHOUSE EFFECT

The Greenhouse Effect
Issue Statement
While some people believe the earth's climatic changes are due to the fact that the
universe is getting older, others believe it is due to the greenhouse effect.
? The greenhouse effect is a naturally occuring phenomenon that is responsible for
trapping heat near the earth's surface and keeping the planet warm. It is called the
greenhouse effect because the way it works is similar to the way in which a green house
functions. In a greenhouse sunlight passes through the transparent roof and walls and
strikes the objects inside- plants, flowerpots, tables, and so forth. These objects
absorb energy from sun, become warmer, and then give off energy themselves in the form of
heat. Only a little of this heat energy passes out through the glass, much of it is
trapped in the greenhouse, raising the temperature inside.
In some ways, the earth functions rather like a greenhouse except on a much larger
scale.
Although the greenhouse effect has only recently been in the news, is nothing new in th
history of our planet, has played major role in making life on earth possible. Without
the greenhouse effect, the earth would be too cold for living thing to survive. The big
question today is If greenhouse effect is natural, why are people so worried about it. Is
soemthing good turning bad? Up until about 150 years ago the compostion of the earths
atmosphere had remianed relatively unchanged for several thousand years. Since mid 1800s
certain human activities have been changing the heat trappin ability of the atmospher
dramatically, as a result more heat is being trapped by the atmosphere. Scientists have
been anticipating this strengthening of the greenhouse effect for sometime, and that it
will lead to a worldwide increase in temperature. This is come true because the world is
getting warmer. Global warming can be expected to change the earth's climate dramatically
and in a relatively short time. As temperatures increase, experts predict that weather
patterns will be disrupted worldwide, the glaciers and polar ice caps will, melt, and
that sea levels will rise. Global warming could change the atmosphere so much and so fast
that all sorts of plants and animals might soon be in danger os extinction. The
greenhouse effect may be the most serious environmental problem the human race has ever
experienced, for this reason scientists around the world are working hard to acheive a
better understanding of the greenhouse effect, to predict the impact it will have on
earth, and to discover ways to control it.
The greenhouse effect occurs when gases such as methane, carbon dioxide, nitrogen oxide
and CFCS trap heat in the atmosphere by acting as a pane of glass in a car. The 'glass'
lets the sunlight in to make heat, but when the heat tries to escape, the gases reabsorb
it. Holding this heat in causes heat waves, droughts and climatic changes which could
alter our way of living. The greenhouse effect, in environmental science, is a popular
term for the effect that certain variable constituents of the Earth's lower atmosphere
have on surface temperatures. It has been known since 1896 that the Earth has been warmed
by a blanket of gases. The gases; water vapour (H2O), carbon dioxide (CO2), and methane
(CH4) keep ground temperatures at a global average of about 15 degrees C. (Oppenheimer,
p. 119-120) Without them, the average would be below the freezing point of water. The
gases have this effect because as incoming solar radiation strikes the surface, the
surface gives off infrared radiation, or heat, that the gases trap and keep near ground
level. Environmental scientists are concerned that changes in the variable contents of
the atmosphere, particularly changes caused by human activities, could cause the Earth's
surface to warm up to a dangerous degree. Since 1850 there has been a mean rise in global
temperature of approximately 1 degree C. (Gribbin, p. 14) Even a limited rise in average
surface temperature might lead to at least partial melting of the polar icecaps and hence
a major rise in sea level, along with other severe environmental disturbances. 
What is meant by the term, the greenhouse effect, is that the heat from the sun comes
into the Earth's atmosphere and cannot get out so it becomes trapped. This effect occurs
when the incoming short wave radiation hits the Earth's surface it changes into longwave,
or infrared radiation. Heat energy in this form is then absorbed and stored in water
vapour and carbon dioxide in the atmosphere.
The main gases that cause the greenhouse effect are water vapour, carbon dioxide (CO2),
and methane which comes mainly from animal manure. Other gases like nitrogen oxide and
man made gases called chlorofluorocarbons get caught in the atmosphere as well. The decay
of animals and respiration are two main but natural sources of carbon dioxide.
Water vapour is an important greenhouse gas. It is a major reason why humid regions
experience less cooling at night than do dry regions. However, variations in the
atmosphere's carbon dioxide content are what have played a major role in past climatic
changes. In recent decades there has been a global increase in atmospheric carbon
dioxide, largely as a result of the burning of fossil fuels. If the many other
determinants of the Earth's present global climate remain more or less constant, the
carbon dioxide increase should raise the average temperature at the Earth's surface. As
the atmosphere warmed, the amount of water vapour would probably also increase, because
warm air can contain more water than cooler air. This process might go on indefinitely.
On the other hand, reverse processes could develop, such as increased cloud cover and
increased absorption of carbon dioxide by phytoplankton in the ocean. These would be
natural feedbacks, lowering temperatures.
Many different things cause The greenhouse effect. The amount of carbon dioxide in the
atmosphere is increased by 0.4 percent each year because of the massive consumption of
fossil fuels such as oil, coal, and natural gas. (McCuen, p. 77) Another contributing
factor is the amount of forest logged. Every second of the day the area of a football
field is cleared of trees by either being logged or burnt. Two other deadly greenhouse
gases which are entering the atmosphere even faster than carbon dioxide are methane and
chlorofluorocarbons, although they are not as damaging in the long run.
These increases are likely to affect worldwide temperatures dramatically. In 100 years
time the average temperature for most parts of the world will increase from between 2
degrees C to 6 degrees C if greenhouse pollution continues at its present rate. (Baines,
p. 190) This temperature increase would drastically affect the growth of many different
crops and cause the polar ice caps to melt, thus increasing sea levels. If this rise in
sea level was to occur many areas would be much more prone to flooding, and generally
much deeper floods would be experienced than nowadays. This flooding would happen
particularly around coastal regions worldwide, and also along many rivers that flow to or
from coastal inlets.
The greenhouse effect is very important because it leads to rising water levels and
temperatures which can have a large effect on the world's climate. Changes in the climate
can lead to significant changes in agricultural industries. This can lead to good
farmland becoming deserts, make it too hot for some crops to grow or let pests and
diseases thrive. As a result some countries can suffer bad economic conditions and people
will have to move. 
It would seem logical that the entire world should try and slow down the emission of
greenhouse gases and/or find ways to balance the gases so the climate doesn't change so
rapidly. If it did we would be forced to adapt to the new climate that we brought upon
ourselves. If we had an international cooperation to put a damper on the production of
chlorofluorocarbons and slow down the use of fossil fuels it would dramatically slow down
the process of global warming.
Over the last 100 years the global temperatures have been increasing slowly but steadily.
Since 1980 the temperature has risen 0.2 degrees C each decade. (Clayton, p. 113)
Scientists predict that if we continue putting the same amount of gas into the
atmosphere, by the year 2030 the temperature will be rising by as much 0.5 degrees C or
more per decade. Overall, the global temperature could rise anywhere from 5 to 9 degrees
over the next fifty years.
If the temperatures do rise as predicted several things could happen. The increases of
temperature could alter the growth of crops in areas near the equator due to insufficient
rain and heat. This could really hurt countries that rely on imported food supplies. With
the introduction of high temperatures in the arctic regions the polar ice caps could melt
and cause the sea water level to go up 1 to 3 feet, this of course would occur gradually
over an extended period of time. This increase could take out small islands, coastal
cities and some shallow rivers. The Everglades in Florida would almost be totally wiped
off the map. The Everglades are home to many animals and plant species. If it did get
flooded, they would all have to move northward across into very dry land, which they
would not be able to endure living on for very long. When the hot temperatures do spread
southward and northward, tropical diseases will be hard to deal with, causing more deaths
and illnesses than before. The financial problem with this is that the flooding will
cause dams to be built and cities to be reconstructed. The shortage of food will cause
the price of the food to go up and with all the diseases we will need more medical
supplies and workers. All of this combined could and will cost a lot of money if we don't
do something about it now.
The computer models can't predict exactly what the climate is going to be in the future,
but they can come close to what it will be like down the road. Scientists proved this by
predicting with computers what the climate was in the past. Then by looking back in the
records, they found that the predictions were close to being right.
The Topex (Topographic Experiment) satellite has been collecting information on the
changes of the sea level, temperatures across the globe and the amount of gases emitted
into the atmosphere. Each day the satellite makes 500,000 measurements, each at a
different place on the Earth's surface. Measurements are all made between 66 degrees
north and south latitudes.
The Cretaceous Period occurred over 100 million years ago. It was the warmest period we
have knowledge of yet. There was so much carbon dioxide in the air that the oceans rose
many metres. North America was flooded and split apart into two pieces. The temperature
then was more than fifteen degrees greater than the average temperature today.
Scientists believe that the tilt of the earth's axis changes to tilt the opposite way
every 10,000 years like a cycle. While going through this cycle it will change the
climate of areas. Right now it is moving so that North America is going to be close to
the sun in the winter. Seasons become more extreme when the opposite happens. This
controls the cycle of ice ages. When volcanoes erupt they send clouds of dust into the
air blocking sunlight. This would cool the earth off more. Oceans are known to absorb
carbon dioxide because of the ocean currents and the action of plankton. There is some
evidence that there is naturally rapid climate change between each Ice Age, which
confuses the whole idea of global warming.
It is necessary that every human being should take part in the fight to stop global
warming. The government is the key to this and they better do something soon or it will
be too late. First, the Canadian government should sponsor a meeting between the nations
of the world. They should establish a committee for handling the money, politics, and
scientific research, in order to help cut back the emission of gases into the atmosphere.
Every country will contribute by donating money. Each country would be required to give
0.01 of their GNP to this committee. If they refuse they will be boycotted and nothing
will be sold to them by participating countries.
Global warming is a big threat to our nation and the world. If we do not act now, it may
be too late. Of course, there is no sure way of telling if there is a greenhouse effect,
but let's not take any chances. Look at what is happening to this world, and you will see
that there is a pollution problem. There are steps being taken at this moment to reduce
the gases put into the air but this is still not enough. We need to cut back more by
taking a few easy steps. Plant a tree, or take the bus to work or school instead of
driving your own car. Those things might not seem like a lot, but if more and more people
do them, they will make a difference.