Greenhouse effect and global warmingCarbon dioxide and water vapor are naturalcomponents of air. As such, they havegenerally not been considered pollutants.However, the voluminous amount of carbondioxide and water continously spewed intothe air by motor vehicles and factoriesworldwide has become alarming.
Greenhouse effect and global warmingIncreased amounts of carbon dioxide andwater vapor have possible long term effects.The maxima of solar radiation which entersthe earth is in the shorter wavelenghtultraviolet and visible regions.
Greenhouse effect The earth also radiates enrgy butits maxima is in the longer wavelenght infrared region Both carbon dioxide and water vapor molecules are not by affectedby incoming shorter wavelenght solar radiation but they absorb heat (infrared radiation) given off by the earth.
Greenhouse effect and global warming This heat is released back to the lower atmosphere as their molecules vibrate. This is called the greenhouse effect. Both carbon dioxide and water vapor are called greenhouse gases.
Greenhouse effect and global warming But there is less problem with water vapor because its concentration in air remains fairly constant. On the other hand, the amount of carbon dioxide in air has tremendously increased in the past century because of man’s activities, mainly the burning of fossil fuels about 3 g of carbon dioxide is produce for every gram of fossil fuel burned.
Ozone DepletionOzone depletion describes two distinct butrelated phenomena observed since the late1970s: a steady decline of about 4% perdecade in the total volumeof ozone in Earths stratosphere (the ozonelayer), and a much larger springtime decreasein stratospheric ozone over Earths polarregions.
Ozone Depletion The latter phenomenon is referred to as the ozone hole. In addition to these well-known stratospheric phenomena, there are also springtime polar tropospheric ozone depletion events
Ozone DepletionIt is suspected that a variety of biologicalconsequences such as increases in skincancer, cataracts, damage to plants, andreduction of plankton populations in theoceans photic zone may result from theincreased UV exposure due to ozonedepletion.