The Greenhouse Effect And Its Implications
Some information for those who may not know much about the causes and implications of the 'Greenhouse Effect'
For those of you who have been living under a rock or asleep for the last 20 years or those who want to know more about it, here is a brief article.
'The Greenhouse Effect maybe the most important natural phenomena and may lead
to major changes in our lifestyles within our lifetime.
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What is the Greenhouse Effect'
The Greenhouse Effect is the culmination of various Greenhouse gases that have been trapped in the Earth's stratosphere that is leading to the changing of the word's climate.
'Under the influence of the sun's rays, the earth's temperature varies from 0 to about 50oC with an average through night and day, winter and summer, of about 15o C
'The warming is done by rays from the sun, including the very shortest, ultraviolet (UV) rays and the longest infra-red (IR) rays which give you that warm feeling when you walk out into the sunshine, much like an electric radiator warms you when you turn it on and get close to it.
'Some of the incoming rays are reflected back by the clouds in the sky and others by the sea and land, particularly deserts and snowfields.
'Not all those reflected rays go back into space, instead, the atmosphere re-radiates many of the IR rays towards the earth making it warmer still. It is this ability of the atmosphere to re-radiate warm rays which creates the Greenhouse Effect.
'Water vapour, carbon dioxide and certain other trace gases, absorb some of this radiation and prevent it being sent back into space. This 'blanket effect' keeps the earth warm.
History of the Greenhouse Effect
It is not a new phenomena or concept. The term 'Greenhouse gas' was first used in the Nineteen Century, by Irish born scientist John Tyndall in a paper he wrote in London's Philosophical Magazine in 1863.
It wasn't until the 1960's that Professor Bert Bolin of Stockholm University worked on the phenomenon. When he discussed it with fellow scientists they said 'This is science fiction. We don't believe it'. However by the mid 1970's things were starting to change rapidly as scientists were starting to accept he was right.
How do we know the Greenhouse Effect exists' What is the evidence'
1. Scientists have analysed climates on planets like Venus and our moon.
Venus which is covered by a very dense atmosphere of carbon dioxide. Its surface
temperature is around 500o C. Whilst the moon which has no atmosphere has an
average temperature of approximately -18oC. Our atmosphere keeps the surface
of our earth, with an average of 15o C, some 33o C warmer and thus habitable.
2. Evidence of ice cores
Over the past 160,000 years carbon dioxide and methane levels trapped in ice
cores have varied with global temperature. Scientists have been able to drill
out ice cores from the Arctic and Antarctic and measure the levels of carbon
dioxide and methane.
3. Increase in surface temperature of approximately 0.5oC over 100 years as
carbon dioxide levels increase
Studies conducted by scientists have concluded that the earth's temperature
remained fairly constant until the start of the Industrial Revolution. Indeed
it did not change much until the start of the twentieth century.
'From 1880 to 1940 there was a warming of just a quarter of a degree. Most of
it was lost between 1940 and 1970.
'From 1950 to 1980 the average surface temperature was 15oC.
'Between 1970 and 1980 the temperature average went up by three-tenths of a
degree C.
'1987 and 1988 were the warmest years on record
4. Sea levels are rising and small glaciers are melting
Scientists using satellite and imaging technology have been able to monitor
the melting of polar ice caps and glaciers.
What are the results of the Greenhouse Effect
By using very sophisticated computer modeling, scientists have been able to
predict what the world's climate will be like when carbon dioxide levels have
doubled.
1.Increase in world's temperature
It is thought that there will be an increase in the average global temperature
by between 1.5 and 4.5oC .
'By year 2030 an increase of 2oC, by 2100 an increase of 6oC.
The warming will be greater at higher latitudes and in winter. This will lead
to the melting of polar ice caps and glaciers which is already evident, in places
like Greenland, the Arctic and Antarctic.
