There have been many natural disasters: Tsunami, storms, earthquakes, floods, cyclones, hurricanes and eartquakes. Some scientists believe that global warming is the cause of may of these. October 16 was declared Ozone (global warming) Day.
The Earth has an ozone layer 10-50km from the Earth's surface. It converts the sun's radiation [the solar flux density is 1353 W/m2] to heat energy. It prevents many harmful rays such as cosmic rays (99%), ultra-violet rays (78%)and infra-red rays(4%). As a result the Earth receives more energy from the sun as electro-magnetic radiation.
The earth's surface absorbs solar energy and releases it back into the atmosphere as as infra-red radiation, some of which goes back into space (about 50%).
There are many gases in our atmosphere that contribute to global warming CO2 (burning of carbon fuels), CH4 (anaerobic bacteria), N20 (fossil fuel and fertilisers), CFC/CFC3 (refrigerators and sprays), SF6, S02, CH3SF3, CH2 and CO(vehicle fumes).
CFC, carbon tri-chloro fluoro and SF6 absorb heat very efficiently and are critical components in the greenhouse effect. These gases absorb the infra-red radiation emiited by the Earth and re-radiate the energy as heat back to the Earth causing greenhouse effect warming.
Ozone holes were discovered by scientists at the British Antarctic Survey over 20 years ago. The Montreal Agreement in 1987 agreed to ban CFCs.
The collection of meteorological data from observation satellites and samples taken from glaciers and trees confirms what many of us already know - the globe is warming up. It is generally agreed that by 2030/40 average global temperatures will have risen by 5degC causing ice caps and glaciers to melt and sea levels to rise. Failure to take action carries a dangerous risk.
As debates continue amd governments fail to act it is becoming more likely that we will be able to see for ourselves whether the dire predictions have been overstated by the middle of this century.
PARANEETHARAN
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