The Greenhouse Effect is the warming of the air around the Earth. The heat from the sun is trapped by a layer of pollution high up in the atmosphere. The process was first by discovered by Joseph Fourier in 1829 and later studied thoroughly by Svante Arrhenius in 1896. Through the process, the emission of infrared radiation by the atmosphere warms a planet's surface. The process was named after a similar occurrence that was found to be taking inside a greenhouse, where the air inside the greenhouse was found to be warmer than the air outside the greenhouse. The earth's average surface temperature is about 20-300C warmer than it would be without the greenhouse effect. Other than our planet Earth, Mars and Venus are the two other planets that have greenhouse effects.
The Basic Process
Within the earth’s atmosphere are numerous gases such as carbon dioxide, methane and nitrous oxide that are known as greenhouse gases. Greenhouse gases that make up a part of the atmosphere act in similar fashion to the glass panes in a greenhouse. Sunlight penetrates the Earth's atmosphere, going through layer of greenhouse gases. On reaching the planet’s surface, land, water, and biosphere absorb the sunlight’s energy. About 70% of this energy is absorbed, and the rest of the energy is sent back into the atmosphere. Some of the energy passes back into space, but much of it remains trapped in the atmosphere by the greenhouse gases, causing the planet to remain warm.
The greenhouse effect is essential to our planets survival. Without the greenhouse effect, the earth would not be warm enough, and thus not habitable for natural life. Yet, the Greenhouse Effect has to maintain equilibrium i.e. the level of greenhouse gases in the atmosphere must maintain an optimum level. The moment the gases go above the optimum level there is a rise in the temperature of the planet’s surface.
Anthropogenic Greenhouse Effect
With mankind’s increasing industrial production more and more greenhouse gasses are being pumped in to the earth’s atmosphere and thus additional heat is being trapped close to the Earth causing the planet to get warmer and warmer and thus resulting in global warming.
CO2 production has risen over the years due to continued industrial activity such as fossil fuel consumption, cement production, deforestation of tropical forests have increased the carbon dioxide concentrations in our atmosphere. Measurements of carbon dioxide amounts taken from the Mauna Loa observatory indicate that carbon dioxide levels in the atmosphere have increased from 313 ppm (parts per million) in the year 1960 to over 370 ppm in the year 2005. This current amount of CO2 exceeds the ideal amount of Carbon dioxide by close 300ppm. Since carbon dioxide is a known greenhouse, elevated carbon dioxide levels will increase global mean temperature. The Intergovernmental Panel on Climate Change concludes that "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations".
In the period of the past 800,000 years, ice core data clearly reveals to us that carbon dioxide levels in the atmosphere have varied from values as low as 180 parts per million (ppm) to the pre-industrial level of 270ppm. Most paleoclimatologists consider variations in carbon dioxide to be a fundamental factor in controlling climate variations over this time scale.
- Climate Change Kids Site