Greenhouse Gas Emission: Causes & Sources

Greenhouse gases are a group of compounds that are able to absorb heat (longwave radiation) in the atmosphere, keeping the Earth's surface warmer by allowing the direct sunlight (relative short wave energy) to reach to the Earth’s surface. The presence of these gases in excess enhances the greenhouse effect which is creating global warming and consequently climate change. An imbalance of the greenhouse gases will be even more harmful if we do not control the rapid increase of these in the Earth’s atmosphere.

Greenhouse effect

The process in which thermal radiation from Earth is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions is greenhouse effect. The ability of the gases to trap heat in the thermal form and spread evenly at the earth’s surface helps to control the temperature on the earth. This even spreading of natural green house gases is responsible for the heat required to sustain life on Earth.

Greenhouse gases

A greenhouse gas (GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. Some of the greenhouse gases which are naturally present in the atmosphere are:

• Carbon dioxide (CO₂)
• Methane (CH₄)
• Water Vapour
• Nitrous oxide (N₂O)
• Fluorinated gases

Some of the gases are called synthetic greenhouse gases or manmade GHG. They are:

• Chlorofluorocarbons (CFCs)
• Hydro fluorocarbons (HFCs)
• Per fluorocarbons (PFCs)
• Sulphur hexafluoride (SF₆)

Consequences of rapid increase of greenhouse gases

Greenhouse gases have direct effect on the temperature of the Earth. The normal temperature of the Earthwill is 32.5°C colder than the present average of 14.4°C.

The presence of greenhouse gases is like a blanket which covers the Earth’s surface by protecting the emission of Infra Red rays from the Earth. Along with the rapid growth in industrial activities in the 19^th and 20^th centuries, human activities have increased the level of the presence of these gases within the Earth's atmosphere.

The natural greenhouse gases get mixed with the water vapour and act as a thermal heater for the Earth, absorbing heat and warming the surface to sustain human life on the Earth. The natural process does not change the temperature level suddenly. It takes years to have any significant change in the climate. So the importance of maintaining the same level has become the need of the hour.

The heavy presence of greenhouse gases results in Global Warming. Few synthetic gases in the atmosphere block the heat from escaping while few spoil the natural gases present in the air.

Dispersion of these gases in more than the required amount may disturb life on the earth. One of the major reasons for the absence of any life form on other planets is that they do not have greenhouse gases.

Measures to reduce the effect of Global Warming

We have reached an era where we can stop using the greenhouse gases. The carbon dioxide level is drastically increasing. Some of the precautions which we can take to reduce the greenhouse effects are:

1. More fuel-efficient cars, vehicular pollution control and less usage of automobiles can reduce the level of carbon dioxide.
2. Sensible and less use of home appliances like TV, AC, electricity, bulbs can reduce energy consumption.
3. We can increase the use of energy alternatives like wind and solar energy which do not produce any toxic waste and do not emit carbon dioxide in the atmosphere.
4. Tree plantation will be a big advantage which will balance the presence of carbon dioxide in the atmosphere. Fast pace of deforestation for residential and commercial use of land is becoming a serious threat to the existence of life.
5. Some scientific techniques have been proposed, such as the chemical removal of CO₂ from smokestacks. Deep underground reservoirs are invented. Though the benefit of this will be less yet the effect of global warming can be reduced to some extent.
6. Disposal of carbon dioxide in the deep ocean where they will form a semi-stable compound under the cold temperatures and high pressures will also be helpful.