Earth and its climate
In class five in my primary school the geography textbook said sun is a big ball of fire. The fire comes to earth in the form of light and heat. This warmth of the sun is trapped by the invisible mass of gases around the earth we call atmosphere.delhi Updated: Jan 04, 2010 17:43 IST
In class five in my primary school the geography textbook said sun is a big ball of fire. The fire comes to earth in the form of light and heat. This warmth of the sun is trapped by the invisible mass of gases around the earth we call atmosphere.
The atmosphere that is of relevance to our existence is 11 kilometres high from the sea levels. This envelop has a mass of gases estimated to be 5x10 (to the power 18) kgs. The mix has some prominent gases like Nitrogen (78.08%), Oxygen (20.95%), Argon (0.93%) and Carbondioxide (0.038%).
However, the miniscule presence of Carbondioxide has become the most important gas in the last couple of decades. It is because this gas has the ability to trap the heat that sun emits and earth receives.
This trapping of heat makes our earth warm and habitable. The process of trapping the heat is akin to greenhouse where plants are put in a tightly covered area and when the sun rays fall it gets heated up and the as the heat has no way of escaping the area inside the tight enclosure experiences very high degree of temperature as compared to outside. This is the reason Carbon Dioxide (CO2) is termed as a greenhouse gas.
Also there are four other gases and two compound gases that fall in the same category. They are methane, nitrous oxide, hydroflorocarbons, cloroflourocarbons and perflorocarbons. Also earth’s atmosphere has one percent water vapour and it too has capability to absorb heat from sun’s rays radiating from the earth.
Yet as they say too much of even good thing is not right. This very ability of Carbon Dioxide to trap gases is now threatening the very existence of human, plant and animal life on the earth.