explain relation between a green greenhouse effect and global warming
Answers
Carbon dioxide (CO2) is an atmospheric constituent that plays several vital roles in the environment. It absorbs infrared radiation in the atmosphere. It plays a crucial role in the weathering of rocks. It is the raw material for photosynthesis and its carbon is incorporated into organic matter in the biosphere and may eventually be stored in the Earth as fossil fuels.
Most of the sun's energy that falls on the Earth's surface is in the visible light portion of the electromagnetic spectrum. This is in large part because the Earth's atmosphere is transparent to these wavelengths (we all know that with a functioning ozone layer, the higher frequencies like ultraviolet are mostly screened out). Part of the sunlight is reflected back into space, depending on the albedo or reflectivity of the surface. Part of the sunlight is absorbed by the Earth and held as thermal energy. This heat is then re-radiated in the form of longer wavelength infrared radiation. While the dominant gases of the atmosphere (nitrogen and oxygen) are transparent to infrared, the so-called greenhouse gasses, primarily water vapor (H2O), CO2, and methane (CH4), absorb some of the infrared radiation. They collect this heat energy and hold it in the atmosphere, delaying its passage back out of the atmosphere. Since the industrial revolution got into full swing in the 19th century we have been burning ever increasing amounts of fossil fuels (coal, oil, gasoline, natural gas) in electric generating plants, manufacturing plants, trains, automobiles, airplanes, etc. Burning releases CO2 into the atmosphere (much the same as respiration does). These fossil fuels may have formed tens or hundreds of millions of years ago from the buried and preserved remains of plant and animal matter whose carbon originated via photosynthesis.Photosynthesis and respiration in plants, animals, fungi, bacteria, etc. exchange carbon between the CO2 in the atmosphere and carbon compounds in organisms. But humans are now putting this natural carbon cycle out of balance. Because of the emission of CO2 long-stored in fossil fuels the percentage of CO2 in the atmosphere has increased from about 289 parts per million before the industrial revolution to over 360 parts per million and rising. Sometime during the 21st century the concentration of CO2 will be twice what it was before the industrial revolution.
With higher CO2 concentrations come expectations of a stronger greenhouse effect and therefore warmer global temperatures. This was originally proposed by a chemist named Arrhenius about a century ago. Global average temperatures have risen by a small, but measurable amount in the past 100 years, apparently in large part because of the higher level of atmospheric CO2. Global average temperatures are expected to be on the order of 2-5°C (3.6-9°F) higher by the time CO2 doubles the pre-industrial concentration. The temperature rise will be small in the tropics but much greater at high latitudes.