Under the influence of the greenhouse gases, there can be largescale changes in the atmosphere conditions.Twenty years ago nobody believed that the Earth was warming up.Scientists warn that if this heating continues for the next few decades,snow at the poles will melt ,especially in greenland,and shrink it to half its size.Similarly,many places in Antarctic will submerge under large tracts of water. This melting snow is raising the levels of the sea, submergeing small islands and coastal areas.Many coastal cities may be lost too.
The planet has always witnessed a rise in the sea level .In fact there has been a rise of four to six metres in the sea level since the ice ages .This rise came about 1,29,000 years!Presently ,similarly rise in sea level is predicted in just a few decades. With sea levels rising ,disaster in the sea have became common now. Janothan Park,Director,Study of planet earth and Bety Butto -Blisken of the national research centre for temperature ,Colarado,have shown us how the oceans have risen as icebergs have melted,and the seacoast has been taken in by the sea .Some scientists also tell us that if we do not change our habits,more natural disasters will occur. The situition is so grim that if the sea level rise by just about one metre maldives and a few islands in Bangladesh will disappear from the face of the Earth!
The ozone layer protects us from the ultraviolet rays of the sun .However this layer is being destroyed by the chloro fluro carbons[CFC]that are being released into the atmosphere.The ozone layer is formed in the stratosphere about 16-50km above the Earth’s surface. In some parts of the world,especially around the Antartica,Australia,New Zealand,South Africa and other parts of the world ,the ozone layer has thinned considerably,The main reason is the release of ozone depleting substances like cfc’s which are used in appliances like refrigerators ,air-conditioners ,sprays and fire extinguishers.
The chances of the ozone layer getting thinned are more in other seasons than in winter.CFC does not occur in the nature. It gets released into the atmosphere from the appliances we have been using for the last 20 years or so.The CFC problem did not exist earlier and is thus related to our changing lifestyle.Along with CFC’s the other naturally occuring gases that destroy the ozone layer are halons[ bromo-chloro- floro carbons] used in fire extinguishers and in nitrogenous fertilisers.As the ozone layer weakens,the UV-B rays from the sun freely reach the earth. An effect of this is seen in the growing incidence of skin cancer in the countries like Australia.
Ultraviolet rays weaken human resistance to disease.They cause cataracts in the eye.If one percent of the ozone layer is destroyed,scientists say, skincancer can increase by 2 %.The UV-Brays can also affect marine life like aquatic plants,fishes,and birds.They affect production of foodgrains and fisheries too.The Montreal Protocal is aimed at preserving the ozone layer.High temperatures cause ozone molecule to break up and recombine.In the presence of sunlight this process goes on perennially.CFC’s are the most important factor weakening this layer.
As the planet heats up,the use of airconditioners increases leading to the release of more CFC’s which destroy the ozone layer.CFC’s ,even when released in small quantities,are ten thousand times more harmful than the greenhouse gases like carbon dioxide and methane as they trap large amount of heat.It is thus clear that the greenhouse effect and the destruction of the ozone layer depends on each other
