In recent years we have become increasingly aware of how human activities and lifestyles are affecting the Earth’s climate. To understand how this happens, it is necessary to know about the greenhouse effect.
What is the greenhouse effect?
The heat from the Sun’s rays heats up the Earth’s surface and the warmed surface radiates heat back out into space. As it leaves the Earth’s atmosphere, it is trapped by greenhouse gases such as water vapour and carbon dioxide.
Without these gases, heat would escape back into space and Earth’s average temperature would be about 15 degree Celsius colder.
But as the level of the greenhouse gases in the atmosphere increases, the amount of heat trapped also increases, and this results in an overall increase in the temperature of the Earth. This is known as the greenhouse effect.
Effects of human activities on climate:
The climate everywhere on Earth has become warmer by a few degrees. This is called global warming. Various human activities have caused this to happen by bringing about an increase in the level of carbon dioxide in the atmosphere. One such activity is the growing use of fossil fuels in transport and industry.
Carbon dioxide produced from burning of these fuels remains in the atmosphere, thus adding to the greenhouse effect, causing rising temperatures.
Another reason for the increase in carbon dioxide in the atmosphere is the unchecked cutting down of forests. Trees are the lungs of the Earth.
They take in carbon dioxide and release oxygen in the air, thus purifying it for us. Each tree that is cut down contributes to the rising level of carbon dioxide in the atmosphere.
How will the increase in the Earth’s temperature affect us?
Due to the rising temperature, the ice at the poles has started to melt. If this carries on, it will cause the water level of the oceans to rise and flood the low-lying areas of land.
Most of the land of a country like Bangladesh, for example, would disappear under water, making millions of people homeless. Some parts of the world will become drier, resulting in crop failure so the agriculture and livestock will be affected.
What can we do?
We should take care of the forests and not cut down more trees than necessary.
We should plant more trees to replace those that are being cut down.
To decrease our use of fossil fuels we can:
a. Turn off lights and other electrical appliances when they are not needed,
b. Walk or use a bicycle to travel short distances,
c. Travel by bus and train rather than by private cars.
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