Paragraphs on Global Warming and Green House Effects!
The energy of the sun is emitted as heat radiations. Some of the radiations (near infrared rays) penetrate the earth’s surface and some of the heat radiations (longer wavelength heat rays) are absorbed and retained by the earth’s surface.
Some of this absorbed heat is then re-radiated by the heated earth.
The temperature of the earth’s surface is determined by the energy balance between the heat energy reaching the earth’s surface and the heat energy that is radiated back into space.
Fossil fuel based industrialisation and man’s degenerative life-style based on over-exploitation of resources like coal, oil and gases which take generations to regenerate has resulted in an unprecedented rise in the concentration of green house gases like carbon dioxide, methane, chlorofluorocarbons, ozone and water vapour.
These green house gases in the lower levels of the atmosphere act like the glass of a greenhouse. Like glass, they are transparent to the near infrared rays (of short wavelength) but are opaque to the heat radiated by the heated earth (longer wavelength heat rays) and trap them.
By not letting the solar rays to escape into outer space, greenhouse gases add to the heat that is already present on the Earth’s surface. This results in an increase in temperature and is commonly known as the greenhouse effect. (On the global scale, this effect is known as global warming)
The greenhouse effect poses the following serious environmental threats:
(a) Rise in the global temperatures will result in melting of the ice masses in the Arctic and Antarctica regions, resulting in rising of the sea level.
(b) With the consequence there would be submergence of many low lying coastal areas.
(c) Flooding of the coastal areas will cause massive soil erosion and siltation contamination of water and water borne diseases.
(d) In temperate regions, the summers will be longer and hotter whereas the winters will be shorter and warmer.
(e) The already dry sub-tropical regions may become drier and the tropical regions may become wetter.
(f) Desertification, droughts and famine would lead to migration of population and new urbanisation.
(g) Due to increased concentration of carbon-dioxide the growth and yield of plants will increase resulting in rapid depletion of nutrients from the soil.
(h) Disruption of the ecosystem by increase in rainfall (9-10%), altered crop patterns and adverse effects on flora and fauna.
To ward off the menace of carbon emissions, the dependence of fossil fuel need to be reduced by encouraging the use of non-conventional sources of energy like solar energy, bio-gas, wind and hydro power etc. Besides controlling grazing and hacking afforestation and reforestation should be encouraged because forests act as carbon dioxide sinks and help to reduce the CO2 concentrations and thereby reduce the greenhouse effect.