What Causes the Greenhouse Effect?
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet’s surface and is reflected upward again as a type of slow-moving energy called infrared radiation.
The heat caused by infrared radiation is absorbed by "greenhouse gases" such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere.
Although greenhouse gases make up only about 1 percent of the Earth’s atmosphere, they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet.
This phenomenon is what scientists call the "greenhouse effect." Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit), far too cold to sustain our current ecosystem.
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 righ