The earth was formed about 4.5 billion years ago. But, the thing that matters the most is HOW LONG will life on it thrive?? It is said that planet Earth would last for about 8 billion years or so until the sun becomes a red giant, destroying our planet. It could even be earlier if a body large enough to destroy the earth collides with it. By then, life on earth would be a history "for our souls" to talk about.
The gradual but unintended changes in our climate due to man's deeds have caused our mother planet to deteriorate, the major cause being global warming and pollution.
Most of the sun's rays reaching the earth are absorbed by the ozone layer present in the stratosphere but presently, the amount of heat and radiant energy reaching the earth and that reflected by the ozone layer is largely contrasting. This is due to the presence of ozone holes in the earth's stratosphere. Ozone is depleted mainly due to its catalytic destruction by atomic halogens formed due to the dissociation of halo-carbon(C-X) refrigerants like CFCs, Freons and Halons. In the presence of UV light, these halo-carbon molecules dissociate leaving free halogen atoms. These halogen atoms act as a catalyst for ozone depletion. The growth of these ozone holes are more pronounced towards Antarctica. The decrease in the thickness of the ozone layer causes the UV rays to penetrate to the surface causing sunburns, skin cancer, cataracts, reduction in the phytoplankton population in the oceans and damages to plants.
The Greenhouse Effect also accounts for the increase in the surface temperature. A greenhouse is made of transparent material like plastic or glass.It mainly heats up because the Sun warms the ground inside, which then warms the air in the greenhouse. The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air aloft. The earth itself can be considered as a greenhouse. The major greenhouse gases include water vapor(35-70%), carbon dioxide(9-26%), methane(4-9%), ozone(3-7%). A part of the sun rays reaching the earth surface are reflected by the earth surface. These green house gases warm the earth by re-radiating some of the energy back towards the surface.As a result of the increase in temperature round the world, the silicate rock cycle speeds up, removing carbon dioxide from the atmosphere and depositing it as calcium carbonate in the oceans. Thus, plants won’t be able to survive, and everything depending on them dies too.
The most important source of these harmful gases is from the emissions from industries, motor vehicles, refrigerators etc. The concentrations of CO and methane have increased by 36% and 148% respectively since 1750. These levels are much higher than at any time during the last 800,000 years. The unlimited use of petroleum have caused not only its diminish but also an increase of about 20% of CO over the past twenty years. The excessive cutting of trees have made the natural cycles unstable and they have contributed for about 60% increase in the CO content. The increase in population have caused more industrial production, more felling of trees and hence, larger accumulation of greenhouse gases. So to control these adverse effects to a large extent, we have to change our life style. We have to lessen up the usage of fossil fuels, control the emissions from industries and motor vehicles, support afforestation and important of all, abide to the 3 R's(Reduce, Re-use and Recycle).
According to the present assessment, life on earth wouldn't survive beyond a period of about half a billion years or so if this continues to be the situation.
Most important of all is to understand that we humans are the ones who make up our destiny. It's time we introspect and make changes to our lifestyle so that our future generations live in peace.
