YEAR 2020 - CONSEQUENCES OF POPULATION-GROWTH AND DEVELOPMENT ON DEPOSITION OF OXIDIZED NITROGEN

With a current world population of 5.3 billion, fossil fuel and biomas s burning have already greatly increased the emission of fixed nitroge n to the global atmosphere. In 2020, with a projected population of 8. 5 billion and an assumed 100% increase in per capita energy consumptio n relative to 1980 by the lesser developed countries, we predict an ap proximate 25% increase in total nitrogen deposition in the more-develo ped-country source regions such as North America. In addition, reactiv e nitrogen deposition will at least double in less-developed regions, such as SE Asia and Latin America, and will increase by more than 50% over the oceans of the Northern Hemisphere. Although we also predict s ignificant increases in the deposition of nitrogen from fossil-fuel so urces over most of the Southern Hemisphere, particularly Africa, the t ropical eastern Pacific, and the southern Atlantic and Indian Oceans, biomass burning and the natural sources of nitrogen oxides (lightning and biogenic soil emissions) are also important in these regions. This increased deposition has the potential to fertilize both terrestrial and marine ecosystems, resulting in the sequestering of carbon. Increa ses in nitrogen deposition have also been shown not only to acidify ec osystems but also to increase emissions of nitric oxide (NO), nitrous oxide (N2O), carbonyl sulfide (COS), and carbon + sulfur (CS2) to the atmosphere and decrease methane (CH4) consumption in forest soils. We also find that the atmospheric levels of nitrogen oxides increase sign ificantly throughout much of the Northern Hemisphere and populated reg ions of the Southern Hemisphere. This increase may lead to larger ozon e concentrations with resulting increases in the oxidative capacity of the remote atmosphere and in its ability to absorb IR radiation.