How Serious is the Greenhouse Effect?

What is the greenhouse effect?

The Earth is surrounded by an enormous atmospheric layer able to absorb the sun's shortwave radiation and prevent the Earth from becoming too hot. After the Earth absorbs the heat of the sun's rays it releases it as long wave radiation. When this happens, the atmospheric layer blocks some of the long wave radiation from dissipating into space thus giving the earth a constant average surface temperature of 15 degrees Centigrade.

This effect is like that produced by a greenhouse, which encloses plants under glass or a transparent plastic cover that allows a certain temperature to be maintained inside to provide advantageous conditions for plant growth.

It is this layer of the atmosphere with its "greenhouse gases," including hydrogen, carbon dioxide, methane, nitrous oxide, fluorocarbons and ozone, that maintains the Earth's temperate atmosphere.

Greenhouse effect out of control!

Originally the greenhouse effect had an important function--it kept the Earth's temperature moderate and promoted the growth of life. But since the industrial revolution, the burning of coal, oil and natural gas has released large quantities of carbon dioxide (CO₂) into the atmosphere. In addition, the production of concrete and freon, the cutting down of forests, opening of wetlands, and creation of landfills have led to a constant increase in the amount of greenhouse gases. Because of this the atmosphere is absorbing more long-wave radiation with the result that in the last 100 years the Earth's atmospheric temperature has risen faster than it had in the previous 1000 years. Of all the greenhouse gases, CO₂ is by far the most prevalent and is responsible for 55% of the rise in atmospheric temperature, thus is has become makind's public enemy No. 1.

The impacts of greenhouse effect

1.Rise in sea level

Because a rise in temperature causes ocean waters to expand, the glaciers at the North Pole and Greenland are melting, and the 0.6 degree rise in temperature has already led to a rise in global sea level of 14 cm. The UN estimates that in the next 100 years the sea level will rise between 15 and 95 cm. When the rise in sea level reaches 50 cm, some 92 million people living in coastal areas will be made homeless because of flooding.

Added to all this, the Himalayan glacier at the "roof of the world" is rapidly receding, and this might create widespread flooding of the seven great Asian rivers that it feeds--including the Yangtze, Yellow River, Ganges, and Mekong.

2.Frequent droughts and floods

The frequent rain storms and droughts that the warming atmosphere brings with it will lead to an unequal distribution of water resources, and wars over these resources may break out in anticipation.

3.Disease carriers

The warmer the atmosphere becomes and the longer it continues to remain warm, the more conditions favor the spread of disease by carriers. Communicable diseases like malaria, dengue fever, and yellow fever may even invade the temperate zone, and plant pests will wreck havoc on agriculture.

4.Ecological dangers

To respond to climatic changes plants will have to migrate to higher elevations at a speed of 1.5 to 5.5 cm a year, yet many plant populations have a migration rate far slower than the pace of climatic change. The result will be an increasing decline in number, and even extinction, of these populations. Correspondingly, animals, which depend upon these plants, will also die out. This is a problem before which mankind will be utterly powerless.

Necessity of reducing greenhouse gases

CO₂ has a life of 50 to 200 years. The UN estimates that in 1992 the amount of CO₂ in the atmosphere had increased 30% since the industrial revolution. If in the 21st century we want to keep to a level of twice that of the industrial revolution, then the world's CO₂ emissions will have to be reduced by more than half.