Sulphur dioxide and nitrogen oxides emitted into the air as industrial wastes can travel thousands of kilometres before they are returned to earth as acid rain. Even remote areas of Scandinavia are affected in this way. Lime in the form of powdered limestone is deposited into affected rivers or spread by helicopter. Limestone, or calcium carbonate, is alkaline and counteracts the acidity. It is also applied the raise the pH of soils with excessive sodium.
Sweden has the world's most comprehensive liming programme. It spends around $24 million a year to treat 5,000 of its 85,000 lakes and hundreds of rivers. Norway, in a similar position to Sweden, has nonetheless decided against large-scale liming because it would divert political attention from the cure - reducing air pollution at its source. Many countries in Europe are also cautious about using lime because of the environmental damage it can cause. Spreading it on bogs around lakes or rivers kills mosses and lichens that act as sponges. By destroying the bogs, sudden floods can occur. The dilemma of whether or not to lime is particularly acute in Wales where acid rainfall is unpredictable and one third of the fallout occurs on less than 5% of wet days. Dosing rivers with the right amount of lime at the right time is extremely difficult, and the risk of overdosing very real.
Conservationists argue that lime only treats the symptoms of acid rain. It simply exchanges one environmental problem for another. Lime does not always neutralize acid water neither does it always ensure that fish populations return.
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.