The Ozone Layer

The Ozone layer

Since the 1960's the ozone layer has greatly depreciated because of man made compounds. The thinning of the Ozone layer causes many problems to the Earth's environment and animals. When the Ozone layer thins out more UV rays reach the Earth's surface from the sun. Three effects this can have is Skin cancer, reduction in the production of crops and the destruction of phytoplankton. There are many different compounds that cause the loss of stratospheric ozone. CFC's and Methyl Bromide are two major causes to the thinning of the Ozone layer. In the stratosphere small amounts of Ozone are constantly being broken down and being formed again. Due to the fact that these two reactions are happening at the same speed there is a natural balance of ozone. When CFC's became widely used this balance was affected and the speed in which ozone was broken down was twice as fast as the speed in which it was formed.

CFC's and Methyl bromide destroy the Ozone layer in a much the same way. Once they have reached the stratosphere the UV rays cause the CFC and Methyl Bromide compounds to split. Once it has split the chlorine and the bromine then acts as a catalyst to break down Ozone. Each bromine and chlorine atom can break down thousands of Ozone molecules. Bromine works a lot more efficiently at destroying Ozone compared with chlorine. Due to the Montreal Protocol most CFC's have been phased out but they are scheduled to be completely banned by 2010. Like CFC's, HCFC's, methyl chloroform, halons, carbon tetrachloride and methyl bromide are meant to be phased out with in the next 40 years.

The Montreal Protocol was set up due to the hole that was appearing over the Antarctica. It successfully phased out most CFC's. Methyl bromide which destroys Ozone 50 times faster than CFC's is yet to be phased out but the amount being used has been reduced down to a quarter of was it was in 1991. Methyl bromide was meant to be phased out in 2005 but that date has been continually pushed back to 2010. Due to the fact they are prolonging the phasing out of methyl bromide the atmospheric concentrations are increasing and therefore they are doing a lot of damage to the ozone. The main use for Methyl Bromide is as a soil fumigant. Countries are wavering there commitment to the banning of methyl bromide by allowing it to be used as a soil fumigant and for quarantine. Farmers have been exempted from the ban of methyl bromide on the grounds that there is no other feasible alternative. Many people claim that there are other more environmentally friendly alternative but farmers do not want to have to pay more money for them. Many farmers have adopted new methods for controlling pest, so there is no reason that farmers can't use other