ANTHROPOGENIC MOBILIZATION OF SULPHUR AND NITROGEN: Immediate and Delayed Consequences

Global mobilization and dispersal of sulphur (S) and nitrogen (N) have been significantly increased by human activities. They are projected to increase even more in the future owing to growth in population and per-capita consumption of food and energy in the developing world, primarily Asia. Increased mobilization and distribution result in changes in precipitation acidity, ecosystem alkalinity and nutrient status, tropospheric and stratospheric ozone concentrations, and energy balance of the troposphere. Although increases in S and N mobilization cause increased environmental impacts, a leveling or decrease in mobilization does not result in a lessening of environmental impacts because of the accumulation of reactive S and N in environmental reservoirs. As S and N accumulate, ecosystems become saturated and S and N dispersal increases. Environmental impacts will only begin to lessen if mobilization rates decrease and as accumulated reactive S and N are converted to nonreactive forms or stored in long-term reservoirs.