Greenhouse effect is trapping of heat in the lower level of the atmosphere. Water vapours and some gases, present in the lower level of the atmosphere, absorb heat and this heat ultimately causes increase global warming.
How gases and vapours form and mix with the lower level of atmosphere? Carbon dioxide is produced by burning and respiration of human beings and animals. Methane gas is produced by insects and other animals, and nitrous oxide is outcome of use of nitrogen fertilisers. Industrial revolution has been increasing the amount of this gas in atmosphere. From the time of beginning of industrialism till mid of 20th century, the amount of this gas in atmosphere increased by 100 percent. Due to this increase, the mean surface temperature of the world has risen by one degree centigrade and it is likely to increase by five degrees by the end of the 21st century.
Fine particles in air, including soot, sulphates and organic aerosols, penetrate human tissues deeply and cause respiratory and cardiac problems. A recent study found that air pollution in France, Austria and Switzerland causes 500,00 asthama attacks and 40,000 deaths per year. Air pollution in developing countries such as India, Pakistan and China is even more severe trends. in the emission of greenhouse gases, particularly of carbon dioxide continue beyond another 100 years major climatic changes can be expected. Greenhouse warming could cause a rapid melting of some polar ice, resulting in rise in sea level and the consequent flooding coastal areas and ultimately sinking of many island like Maldives and Marshal Islands. It would be also devastating to people living in Bangladesh and on the rule and forest fires. It increases evaporation, which leads at other pieces, to heavier rainfall and floods. Carbon dioxide would have not increased to such levels as it is now if the natural forests had not been cleared by increasing population. This deforestations is quite visible in the Amazon and in the equatorial forests of Africa. Trees and Plants consume atmospheric carbon dioxide and release oxygen. At present, the measures which are being taken to reduce the production of carbon dioxide would take time, at least 50 years to give some results.These measures would include development of both technologies and strategies to deal with it.