By: Tobi Nagy
The Greenhouse Effect maybe the most important natural phenomena and may lead to major changes in our lifestyles within our lifetime. Today, whenever there is a natural disaster, the Greenhouse Effect seems to be on the agenda. It wasn’t so long ago that scientists were dismissive of the Greenhouse Effect and there are some still that do not believe it exists, just like there are still people out there that think the world is still flat and the Holocaust never existed. So what is the Greenhouse Effect?
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 500 deg C. Whilst the moon which has no atmosphere has an average temperature of approximately -18 deg C. Our atmosphere keeps the surface of our earth, with an average of 15 deg C, some 33 deg C warmer and thus habitable.
- 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.
- Increase in surface temperature of approximately 0.5 deg C 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 15 deg C.
- 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 and since then temperatures have been increasing. In 2009, Victoria Australia, experienced the hottest two days on record- 46 deg C, and one of the days (February 6th) leading to Australia’s worst natural disaster in which over 170 people died as a result of bushfires.
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.