CFCs and their effect on the ozone layer.

The environment is a huge area of study; it is cross discipline covering geology, physics, chemistry, biology, politics, economics, geography, philosophy, ethics………the list goes on. A definition of the environment is threefold: 1. A computer environment consisting of systems and programs 2. The external conditions, factors and surroundings in which people, animals and plants live or work 3. For the purpose of conservation and ecological studies – the influence of external factors affecting the behaviour, development and habitat of animals and plants.

Climate change is one aspect of item 3 above. There are many reasons for climate change both natural and anthropological (man made). CFCs are one of these. Chlorofluorocarbons are volatile gases containing chlorine, fluorine and carbon. They are found, for example, in aerosols and fire extinguishers as propellants, air conditioning units, degreasing solvents and refrigerators, causing depletion of the ozone layer.

The tropospheric ozone layer acts as a shield blocking harmful ultra violet rays (UV-B) from the sun allowing life on earth to exist. Scientific evidence suggest that man made compounds can be highly stable lasting many decades and reaching higher levels of the atmosphere than naturally occurring compounds. Unnaturally large amounts of chlorine reacting with ozone causes depletion of this layer. It is estimated that some 80% of chlorine is man made whilst the remaining 20% comes from the oceans and volcanoes! CFCs are not limited to ozone depletion and have a higher potential to increase the greenhouse effect than carbon dioxide. Effects of ozone depletion and high levels of UV-B include increased incidents of skin cancer, cataracts, premature skin aging, damage to the immune system, creation of ground level ozone in the form of smog and damage to aquatic and terrestrial plant life.

Interesting to note that James Lovelock’s research in the Arctic and Antarctic during the 1960s and 1970s concluded that CFCs are NOT hazardous. However, Sherry Rowland and Mario Molina, in 1974, discovered that CFCs have a lifespan of some 100 years, giving them ample time to to diffuse into the troposphere. Indeed, their low initial reactivity was considered an attractive feature in the early days!

Manufacture of these gases has been phased out under the Montreal Protocol as a result of the Vienna Convention for the Protection of the Ozone Layer in 1987. Climate projections now indicate that the ozone layer will return to 1980 levels by between 2050 and 2070. The interim replacement for CFCs are hydrochlorofluorocarbons (HCFCs) but will ultimately be supplanted by hydrofluorocarbons (HFCs) having a nil ozone depletion potential. Furthermore, manufacturers of air conditioning units, refrigerators and fire extinguishers are required by law to have certification and are obliged to recycle and ultimately dispose of these units correctly.




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