Earth’s atmosphere trap heat. Arrhenius first refers to this “hot-house theory” of the atmosphere- which would be known later as the greenhouse effect- in his work Worlds in the Making (1903).

The atmosphere allows most of the visible light from the Sun to pass through and reach Earth’s surface. As Earth’s surface is heated by the sunlight, it radiates part of this energy back toward space as infrared radiation. This radiation, unlike visible light, tends to be absorbed by the greenhouse gases in the atmosphere raising its temperature. The heated atmosphere in turn radiates infrared radiation, back toward Earth’s surface.

Without the heating caused by the greenhouse effect, Earth’s average surface temperature would be only about -18C (0F). On Venus the very high concentration of carbon dioxide in the atmosphere causes an extreme greenhouse effect resulting in surface temperatures as high as 450C (840F).

Although the greenhouse effect is a naturally occurring phenomenon, it is possible that the effect could be intensified by the emission of greenhouse gases into the atmosphere as the result of human activity. From the beginning of the Industrial Revolution through the end of the 20th century, the amount of carbon dioxide in the atmosphere increased by roughly 30 percent and the amount of methane more than doubled. A number of scientist predicted that human related.