The Ozone layer is one layer of our stratosphere that sits about 9.3 to 18.6 miles above earth. This Ozone layer serves as a shield that protects us from harmful ultraviolet rays that are emitted from the Sun. It absorbs some of the radiation hitting the earth. Ozone traps a type of radiation called ultraviolet radiation, also called UV light. There are two types of ultraviolet radiation: UVB and UVA. These ultraviolet radiations penetrate the skin, which causes DNA molecules in plants and animals to be damaged. UVB causes sunburn and cancers. UVA penetrates the skin more deeply causing melanoma, a deadly skin cancer. UVA is more harmful than UVB which scientists have just discovered.
The Ozone layer is getting thinner. The thinning is caused by chemicals called chlorofluorocarbons, or CFC’s. CFC’c are mostly in plastic products and refrigerants. When CFC’s reach the upper atmosphere and are exposed to ultraviolet light they are turned into substances that include chlorine. Once chlorine reacts with the ozone molecule it rips it apart. One atom of chlorine can destroy more than one hundred thousand ozone molecules. Ozone molecules are always being reformed and destroyed, but it is hard for the ozone to reform once its broken apart due to the CFC’s in the air.
Carbon tetrachloride, CCI4, is another known air toxin like CFC’s. CCI4 is a chemical once used in cleaning products and is still a commonly used compound in the chemical industry. This gas accounts for about 10-15 percent of the ozone depleting chemicals in the atmosphere today. The compound is included in a list of products to be phased out of production, but rates of this chemical being released is 30-100 times larger than what is being reported to emission inventories. The chemicals global concentration should be decreasing at a rate of about 4 percent per year, but is only decreasing at a rate of 1 percent says Montzka, who works in NOAA’s Earth System Research Laboratory. Analysis of all the data suggests that all the CCI4 emissions come from the same geographic areas as the industries reporting to the EPA.
With a hopeful future, the long-term recovery of the ozone layer looks good. The Montreal Protocol is the first international treaty to be now ratified by all 197 countries. This is an international treaty designed to protect the ozone layer by phasing out certain products that may release gases responsible for the depletion of the ozone layer. Scientists predict that if the international community continues to comply with the Montreal Protocol, then the ozone layer could fully recover between 2050 and 2065.
Destination: Alpha Centauri 