Greenhouse effects & Global Warming
MD. REAZUR RAHMAN
B.Sc. in Textile Engineering
Sec: A (L4T1) Semester: Spring’12
DAFFODIL INTERNATIONAL UNIVERSITY
Table of Contents
|Topic Page No. | |Greenhouse effect |3 | |Everyday examples of the greenhouse effect |4 | |Mechanism of Green House Effect |5 | |Greenhouse Gases |6 | |Annual Greenhouse Gas Emission by Sector |7 | | |8 | |Global Warming | | | |8 | |Effects of Global Warming | | |Some Important Facts about Global Warming |10 | | |11 | |What Can We Do About Global Warming? | | |Conclusion |12 | |References |12 | Greenhouse Effect
The greenhouse effect refers to circumstances where the short wavelengths of visible light from the sun pass through a transparent medium and are absorbed, but the longer wavelengths of the infrared re-radiation from the heated objects are unable to pass through that medium.
The trapping of the long wavelength radiation leads to more heating and a higher resultant temperature. Besides the heating of an automobile by sunlight through the windshield and the namesake example of heating the greenhouse by sunlight passing through sealed, transparent windows, the greenhouse effect has been widely used to describe the trapping of excess heat by the rising concentration of carbon dioxide in the atmosphere. The carbon dioxide strongly absorbs infrared and does not allow as much of it to escape into space.
Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection.
If an ideal thermally conductive blackbody was the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects about 30% of the incoming sunlight, this idealized planet's effective temperature (the temperature of a blackbody that would emit the...