There is only a superficial difference between emergencies and dangerous situations involving pollution and those involving floods and floating ice. The former are often the result of human activity, whereas the causes of the latter are frequently natural. Phenomena which are often purely natural may in some instances be exacerbated, or even wholly caused by human intervention. Floods, for example, may be caused or rendered more harmful by such human activities as the construction of canals or dams or land use practices, such as deforestation, which causes unnaturally rapid run-off. Conversely nature may interact with human activities to produce disastrous consequences, as in the case of flooding caused by earthquake damage to dams. There is therefore a continuum of possibilities ranging from the wholly natural to the wholly man-made.
The conditions most often giving rise to complaints and creating the need for deliberate international planning are those that cause in other countries: shortage of surface or ground-water supply; flooding; siltation; salinization; depletion of fish and elimination of breeding areas; eutrophication; excess vegetation; concentration of salts or other chemicals, untreated sewage, radioactive substances, oil or waste products (introduced from ship or shore); changes in temperature; blockage of passage (fish, vessels, timber); diminishing of scouring; and changes of flow. Even the otherwise innocent and beneficial use of fertilizers, the attempt to control the invasive water hyacinth, the construction of weirs for water storage and flood control, the drainage of a swamp, the cooling of a thermoelectric plant, or the return of irrigation water to the river may produce damaging consequences in other parts of the basin. Although the harm occurs most often downstream, among the numerous exceptions to this general rule are the effects in boundary streams and lakes. Some conditions are likely to be felt both upstream and downstream, particularly when fishing, navigation or timber floating is involved. Another factor which may contribute to water-related dangers is the phenomenon of global warming resulting in either excess or diminished rainfall with the consequent flooding or droughts.
The Encyclopedia of World Problems and Human Potential is a collaboration between UIA and Mankind 2000, started in 1972. It is the result of an ambitious effort to collect and present information on the problems with which humanity is confronted, as well as the challenges such problems pose to concept formation, values and development strategies. Problems included are those identified in international periodicals but especially in the documents of some 60,000 international non-profit organizations, profiled in the Yearbook of International Organizations.
The Encyclopedia includes problems which such groups choose to perceive and act upon, whether or not their existence is denied by others claiming greater expertise. Indeed such claims and counter-claims figure in many of the problem descriptions in order to reflect the often paralyzing dynamics of international debate. In the light of the interdependence demonstrated among world problems in every sector, emphasis is placed on the need for approaches which are sufficiently complex to encompass the factions, conflicts and rival worldviews that undermine collective initiative towards a promising future.
Non-profit, apolitical, independent, and non-governmental in nature, the UIA has been a pioneer in the research, monitoring and provision of information on international organizations, international associations and their global challenges since 1907.