A key issue in freshwater resource management is certainty of supply. Many significant issues are related to freshwater resources and global environmental change. Schwartz et al. A number of researchers have addressed the task of improving the local supply of freshwater from a national or regional standpoint. A present increase in water demand can serve as a surrogate for future lack of supply, however.
Concern is also high for maintenance of a high quality level for freshwater resources.
Achievement of this high level on a global basis, however, may be a long struggle in the face of higher priority concerns such as food production and economic development. Between 1960 and 1987 the surface area of the Aral Sea decreased by 40 percent, and salt and pollutant levels increased significantly, with substantial adverse impacts on human health.