Water

Water is essential for satisfying basic human needs, health and food production, the preservation of ecosystems, and for economic and social development in general. Almost 80% of the water on Earth is in the oceans and over 99% of the fresh water is found in ice caps or deep within the ground. Less than 0.03% of the Earth’s renewable water resources are available in lakes and rivers around the world. Groundwater is ubiquitous but increasingly difficult to obtain and non-renewable. Since the amount of fresh water is essentially fixed, increases in population reduce the per capita availability. To compound the problem, existing sources of fresh water are subject to greater demands for agriculture, industry, domestic use and waste removal as populations urbanise and develop. From 1940 to 1990, the use of water increased fourfold while existing supplies became more and more contaminated with pollutants.

In 1955, water scarcity – defined as less than 1000m³ of water per person per year – affected 20 countries, with a combined population of more than 130 million people. According to Malin Falkenmark, the Swedish hydrologist who developed and defined the concept, water scarcity may impede economic development, since industrialisation increases the demand for water, especially in the early stages of the process. Currently, more than two thirds of the fresh water used worldwide goes to agriculture.

Throughout human history, populations have concentrated in areas of adequate water supplies because of the difficulty of transport. However, the water supplies that led people to settle in some arid areas have been over-extended by rapid increases in human population. This is particularly true in the south western United States and in North and East Africa. In the United States, massive water diversion projects have been used to supply populations with water. Increasingly, there is competition between urban and agricultural interests for available water. Government water subsidies have encouraged inappropriate and inefficient water use. Increasing demands from urban areas are forcing governments to re-evaluate these policies and to permit transfer of water to more productive uses.

In North Africa, the annual per capita availability of water is expected to decline dramatically from 1990 to 2025. Egypt will decline from 1070m³ to 620m³, Libya will fall from 160 to 60; Tunisia (530 to 330); Algeria (750 to 380); and Morocco (1200 to 680). These declines are entirely the result of an increasing population and will put these countries below the generally accepted minimum per capital requirement of 1000m³/year. Most of this water is used for agriculture but increasingly it will be needed for industry thus raising its cost and limiting availability.

An estimated 1.1 billion people were without access to clean drinking water in 1994; 2.8 billion people lacked access to sanitation services. Waterborne diseases infect some 250 million people each year, about 10 million of whom die. Technical advances in desalinisation processes can increase the conversion of sea water but this approach is restricted by location, energy availability, and cost. As populations urbanise, there will be much greater industrial and domestic demands for water and failure to meet these needs will impede economic development.

Human, animal, and industrial waste products are polluting available water on a global scale and limiting the usefulness of local water supplies. Nitrate pollution of groundwater is a serious problem throughout agricultural areas of the world.

Source: Adapted from: Environment for People: Building Bridges for Sustainable Development, UNEP, New York, 1997, pp. 4-9.