The diagrams show how radiation from the sun reaches the Earth and how the greenhouse effect works. The greenhouse effect happens when heat radiation from the sun is trapped inside the Earth’s atmosphere.

First of all, heat radiation is produced by the sun. This radiation travels towards the Earth’s atmosphere. About twenty per cent of the sun’s radiation is scattered and reflected by clouds. Six per cent of the radiation is scattered by the Earth’s atmosphere. Approximately twenty per cent of the radiation is absorbed by the Earth’s atmosphere and by clouds. Just over half of the radiation is absorbed by the Earth. As a result the Earth is warmed by the sun’s radiation.

At night some of the Earth’s heat is lost. Then the greenhouse gases in the atmosphere trap and reflect the heat back to the Earth. This trapped heat makes our planet warm enough for life. However, pollution may increase the quantity of greenhouse gases in the atmosphere. More greenhouse gases trap and reflect more heat. This may mean the Earth becomes warmer.