Carbon Dioxide and Other Greenhouse Gases in Ocean, Atmosphere, and Biosphere, and Future Climatic Impacts

Abstract

This chapter discusses the recent anthropogenic changes in carbon dioxide and other radiatively active gases. The concentration of carbon dioxide in the earth's atmosphere is about 340 ppm in volume; it is increasing at a rate in excess of 1 ppmv/year. By the latter half of the next century, atmospheric carbon dioxide could be more than 600 ppmv, which is double the pre-industrial values. Three-dimensional, general circulation models of the atmosphere indicate that because of various feedback effects, the rise in atmospheric carbon dioxide will probably result in an increase in the earth's average surface temperature of 2–3°C. The warming will be much greater at high latitudes, possibly 9°C in arctic regions during the wintertime. Other greenhouse gases—such as methane, nitrous oxide, and chlorofluorocarbons—are also increasing in the atmosphere at about the same percentage rate as carbon dioxide. This can cause a further rise in temperature, which can be of the same order of magnitude as the carbon dioxide–induced increase.