The Earth's atmosphere allows most of the sun's rays through it to heat the Earth's surface. Much of this heat energy is then radiated back into the atmosphere from where it is lost in space.Because of the build up of certain gases in the atmosphere, less of the heat energy is now being radiated back into space. The result is a rise in the Earth's temperature (a greenhouse retains heat in a similar way). The main gases responsible for this 'greenhouse effect' are carbon dioxide, methane and chlorofluorocarbons (CFCs). If the greenhouse effect continues, there could be major climatic changes. The polar ice caps could melt, causing sea levels to rise and flooding to occur, and many crops will no longer grow. The greenhouse effect was first named by a Swedish scientist Svante Arrhenius in 1905. It was predicted even earlier by a French mathematician Joseph Fourier in 1827.
