The greenhouse effect is, together with our atmosphere and water, what makes life on earth. When the sun’s rays hit the atmosphere, the shortwave rays can pass through the atmosphere while the long waves are reflected. Some of the shortwave rays are reflected and others are absorbed by the earth. The radiation absorbed by the earth is converted into infrared radiation, which is heat radiation. This heat radiation is absorbed by greenhouse gases.
The increased greenhouse effect is when there are too many greenhouse gases in the atmosphere, which can absorb the heat that the earth reflects. Because the atmosphere acts as a duvet above the ground, the heat remains in the atmosphere and causes it to get warmer.