Good morning to our lecturer and my fellow friends. Today I want to deliver a speech on title “Ozone Depletion”.
Did you know that about 20 kilometres from the earth’s surface there is a thin layer of gas forming just a small fraction of the earth’s atmosphere, without which harmful radiation from the sun would destroy all life on this planet? This is the ozone layer, which filters out harmful ultraviolet-B rays. Today, because of our negligence, the ozone layer is depleting.
Ozone depletion occurs when the natural balance between the production and destruction of stratospheric ozone is tipped in favour of destruction. Although natural phenomena can cause temporary ozone loss, chlorine and bromine released from man-made compounds such as chlorofluorocarbons, called CFCs are now accepted as the main cause of this depletion. These are used as propellants in spray cans and in the making of plastic foam. They are also found in cleaning solvents for computers and in the coolants used in refrigerators and air-conditioners. Nuclear testing also is the cause of ozone depletion.
Depletion of the ozone layer causes an increase in the amount of harmful ultraviolet rays that reach the surface of the earth. Every time 1% of the ozone layer is depleted, 2% more ultraviolet rays is able to reach the surface of the planet. Ultraviolet rays increase is one of the most harmful consequences of ozone depletion because it can cause skin cancer. In addition to cancer, decreased ozone layer will increase rates of malaria and other infectious diseases. More cases of cataracts can also be expected.
The environment will also be negatively affected by ozone depletion. The life cycles of plants will change, disrupting the food chain. Effects on animals will also be severe, and are very difficult to foresee. Oceans will be hit hard as well. The most basic microscopic organisms such as plankton may not be able to survive. If that happened, it would mean that...
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