The influence of man on climate

The economic activity of man has lately been exerting a considerable influence on global climate. This influence ranges from the growth of carbon dioxide concentration to an increase in aerosol chemicals in the atmosphere. The first results in a rise in air temperature at the surface of the earth, while the second provides for a fall in temperature. The overall influence of various man-made factors results in a fall in some tenths of degree in average temperature. Because of a rapid growth of the carbon dioxide concentrations and a growth of energy consumption with an extra heating of the atmosphere, it may be expected that a fall in temperature caused by economic activity will give place to a temperature rise in the near future. According to some calculations an average temperature at the surface of the earth may rise in 0.5⁰ by the end of the present century. It may be followed by a considerable reduction in the area of the Arctic ice, by changes in the atmospheric circulation and by the diminution of precipitation in a number of regions.