Man-Made Perturbation of the Nitrogen Cycle and Its Possible Impact on Climate

Abstract

ABSTRACT After a brief discussion of the global nitrogen cycle, manmade perturbations to the cycle are discussed. Estimates of various global fluxes of nitrogen are given, in order to show the extent of human intervention. From different atmospheric nitrogen species nitrous oxide must be expected to produce the most pronounced effect on the thermal structure of the earth's atmosphere when the atmospheric mixing ratios are doubled. This effect, however, is still only about 1/4 of that by atmospheric carbon dioxide when its abundance is modified by the same factor. The rise in atmospheric nitrous oxide to be expected due to the predicted increase in the use of industrial fertilizers and fossil fuels is estimated. Based on this estimate, the range for a possible increase in atmospheric temperature at the earth's surface due to perturbed nitrous oxide, ammonia, and nitric acid levels is determined to be 0.4 – 1.5 °K.