Global Air Pollution and Climate Change

Mankind has now demonstrated that it can change the composition of the atmosphere on a global scale. Those consequences of global air pollution which may have the greatest impact on society in the decades ahead are the associated changes in the radiation balance of the earth and atmosphere and the resulting change of climate. Carbon dioxide increase from the burning of fossil fuels at a continuingly increasing rate can cause a 1°C rise in mean surface temperatures by 2000 A.D., and 2-3°C rise by the middle of the next century. There are uncertainties in this projection of mean temperature rise of perhaps a factor of two; and the polar regions are expected to experience an increase several times larger. Other anthropogenic influences, such as the addition to the atmosphere of chlorofluoromethanes, nitrous oxide, and possibly aerosols, may contribute still further to this global warming. The mean surface temperature of the earth by 2000 A. D., if our projection is correct, will be warmer than at any time in the past 1000 years or more. Accompanying such a climate change there will be shifts in the large scale atmospheric circulation patterns and significant alterations of regional temperature and precipitation distributions-favorable for some regions, unfavorable for others, although we cannot predict the details of these changes.