What causes global warming?

Global warming, a part of climate change, is caused by an increased greenhouse effect.

Greenhouse effect is the effect caused by certain gases in the atmosphere classified as greenhouse gases. The main greenhouse gas is CO2.

In the greenhouse effect, greenhouse gases trap heat. When sunlight reaches the surface of the Earth, some of it is absorbed and warms the ground, and some portion bounces back to space as heat. The greenhouse gases absorb and then redirect some of this heat back towards the Earth. Such heat trapping keeps the temperature of the earth higher than it would have otherwise been.

An increase in the amount of greenhouse gases hence leads to an enhanced greenhouse effect and to a higher degree of global warming.

The greenhouse effect in itself is not bad, as such warming of the earth is needed to a certain extent for our survival. It is the increased amount of greenhouse effect and the increased warming that is creating problems.

Currently, it is estimated that there has been a dramatic increase in the amount of greenhouse gases in the atmosphere, and a range of human activities is said to be responsible for the increased amount of greenhouse gases.