(introduction...)

Juha I. Uitto

The theme of the fifth UNU Global Environmental Forum was "Freshwater Resources in Arid Lands." The title contains the two key phrases "freshwater" and "arid lands." Fresh water is a finite resource and highly unevenly distributed on the surface of the globe. Only 2.59 per cent of the total volume of water in the world is fresh water, and most of it is stored in polar ice masses and glaciers, while only 1 per cent is readily available for human use (Tolba et al. 1992). This small percentage is basically found in rivers, lakes, and reservoirs, and as groundwater.

Freshwater ecosystems are fragile and under severe pressure all over the world. The rapidly increasing population in the developing world is putting heavy pressure on the use of water for the burgeoning cities, domestic consumption, and irrigated agriculture, at the same time as effluents and waste from human settlements, industry, and agriculture are overloading their capacity to recuperate. In the more humid areas of the world, water quality becomes the main concern, with severe impacts on human and ecosystem health, and loss of natural biological diversity, for example. In drier environments, the plain availability of fresh water is the main issue.

Regional water shortages are now becoming commonplace. According to the Washington-based think-tank the Worldwatch Institute, in 26 countries in the world, with a total population of 230 million people, water scarcity limits food production and sanitation and has a negative impact on economic development and environmental protection. In ten of these countries the water balance is actually negative, meaning that they consume more water than is regenerated. With the rapidly increasing population, it is expected that the number of countries experiencing water shortages will increase to 35 by the year 2020 (Brown et al. 1996).

The United Nations estimates that 70 per cent of the world's drylands, amounting to 3.6 billion hectares or one-quarter of the total land area of the world, is experiencing desertification (UN 1992). Desertification is defined as land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. This negative process affects the livelihood of about one-sixth of the human population. Huge amounts of agricultural areas and range land are lost to land degradation and the encroaching deserts, thus undermining the potential of the people to feed themselves. It is estimated that 73 per cent of all range land with an already low potential for human- and animal-carrying capacity is being degraded. Similarly, 47 per cent of drylands at the margins of potential rainfed agriculture is facing declining soil structure and fertility. Land degradation is not an abstract scientific concern: it is very concrete to those depending on the resources that are being degraded and leads to widespread poverty, malnutrition, and environmental refugee flows that can destabilize entire countries and regions.

Some of the worst effects of land degradation and salinization of soils can be seen in irrigated dryland areas where the population densities and agricultural potential are the highest. Declining production in these areas has particularly severe impacts on human life. Irrigated agriculture is, however, essential for feeding the growing world population. Some 40 per cent of the food is produced on the 16 per cent of crop land that is under irrigation (Brown et al. 1996). Without irrigation, the world could not be fed. Irrigation systems, however, are often designed and operated in an inappropriate manner, causing wastage of water and environmental problems. In India, for example, water is a free resource for the farmers and when it is available it is used in a careless and wasteful manner. Irrigation gates are opened, letting the water flood the fields; much of it runs off or evaporates. The availability of abundant under-priced water also encourages the cultivation of wrong crops that are not naturally suitable to the relatively arid environments. Large-scale and inappropriate irrigation development can also result in increased soil salinity and other environmental problems.

A bad example of environmental degradation caused mostly by large-scale agricultural development is the Aral Sea region in the former Soviet Central Asia. This inland sea, that used to be amongst the largest in the world, has today two direct coastal nations, the newly independent states of Kazakhstan, and Uzbekistan. More countries in dry Central Asia, including Kyrgystan, Tajikistan, and Turmenistan, are nevertheless dependent on the water regimes surrounding the Aral Sea. Prior to the 1960s, the Aral Sea area amounted to 68,300 km², with a water surface of 66,100 km² and 2,200 km² of islands. The volume of water was then 1,066 km³ and the maximum depth of the sea was 69 metres (Glazovsky 1995). The water balance of the Aral Sea is dependent mainly on the run-off from two rivers, the Amu Daria and Syr Daria rivers, and on evaporation.

Beginning around the early 1960s, the inflow of water from the two rivers decreased sharply. The Aral Sea basin had been designated as a major cotton producing area by the planned economy of the Soviet Union. It experienced a dramatic population increase from 13.8 million in 1950 to 34 million people four decades later. At the same time, the production of cotton was dependent on irrigation and, consequently, the area under irrigation increased rapidly, with drastic impacts on the water balance of the entire region. By 1990, the sea area had decreased by close to 50 per cent to 34,800 km² and, even more dramatically, the water volume had shrunk by 70 per cent to 304 km³. The sea level dropped by more than 15 metres the same period (Glazovsky 1995). Today, the once-thriving area, where the impressive fishing fleet was the pride of the people and nations, has been reduced to barren land where the fishing vessels lie abandoned, flat, on the dried bottom of what once used to be the Aral Sea. The inappropriate irrigation methods have turned large areas into salinized deserts unable to support agriculture. And the health of the people has deteriorated alongside the environmental degradation and excessive use of chemicals in agriculture, resulting in dramatically increased mortality from cancer, cardiovascular diseases, tuberculosis, and gallbladder and gallstone diseases in the surrounding republics.

The extreme example of the Aral Sea basin demonstrates the vulnerability of drylands to mismanagement by humans. Indeed, while droughts, climatic fluctuations, and other physical factors play a role in the desertification process, the human use and abuse of the resources, including water, is at least as significant for the degradation of arid and semi-arid lands. It is difficult, if not impossible, to distinguish accurately between the relative share of physical and anthropogenic causes (Mainguet et al. 1996).

Aridity and water problems are not only limited to the continental drylands. Specific problems with the availability of fresh water resources are facing small islands. Ironically, islands, which are surrounded by water, are often very short of fresh water and must import much of their water at a high cost. Their limited groundwater resources are further threatened by infusions of salt water. While the islands of the industrialized world are generally in the process of being depopulated, population growth and industrialization are very high in many small island nations, especially in the Pacific. These processes put particular stress on fresh water.

The solutions to these looming and interrelated problems of water scarcity and land degradation must be found on many fronts. The earlier presentations have highlighted a variety of technologies with potential for dealing with these issues. Appropriate technologies can be traditional and low tech, such as the dew-irrigation and water-harvesting techniques utilized traditionally in the Middle East, as described by Professors Kobori and Hillel; or they can be modern, large-scale technologies of the kind of the underground dams built and managed in Okinawa and introduced in the paper by Mr. Osuga. Other technologies, such as reverse osmosis, have been developed and show potential for water desalinization - a technique that can produce water for domestic and agricultural use and reduce the pressure on the utilization of groundwater and surface fresh water in arid lands (Murakami 1995). The important issue is not the level of technology but its feasibility and sustainability.

Apart from technological and environmental concerns, it is important that the solutions are economically, financially, socially, and culturally acceptable. An important issue is correct pricing of water, for industrial, domestic, and agricultural uses. This is, however, a highly political issue and virtually no country has set water prices at the real level. The general feeling often is that how can mankind charge for what falls down from the heavens!

Land degradation and water scarcity have the potential of leading to conflicts between groups of people and between countries sharing the same limited resource. Notably in the Middle East, limited water resources play a central role in the conflict between and among Israel, the Palestinian nation, and the Arab countries. The approach promoted by the United Nations University is to find technically, economically, and socially feasible options that can form the basis of political decision-making. This approach was successfully applied, for instance, at the Middle East Water Forum that contributed to the peace process in the region (Biswas 1994; Wolf 1995).

The world community acknowledges the central importance of limited water resources to sustainable development and is now moving towards an International Water Convention, along the operational lines of the Convention to Combat Desertification already in existence. A holistic approach, encompassing all sectors of society, both technological and environmental, as well as socioeconomic and political approaches, will be necessary for coping with the challenges of fresh water, land degradation, and food production.