Global water resources
Global water resources

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Global water resources

1 Charting the global water situation

In 2000, 5% of the global population was estimated to be water scarce, meaning less than 1000 m3 of fresh water was available per person per year; by 2025 this is estimated to affect 31% of the population. Many of these people are in countries with high population growth rates and their water problems are increasing rapidly.

Figure 1 Global water use and distribution. The bar charts show percentage use by category.
Figure 1 Global water use and distribution. The bar charts show percentage use by category.

The water-scarce countries also have another water problem apart from scarcity—the water is often unsafe to drink. Every year, over 2 million people die from water-borne diseases. So having sufficient water is not enough; it must be unpolluted water. Access to safe water varies with region (Table 1), being lowest in Africa. The access in cities, about 94%, is much higher than in rural areas, where it is only about 71%. Globally, 18% of the population lack access to safe drinking water — and that is over 1 billion people. Lack of safe water is due both to lack of investment in water supply systems and to inadequate maintenance of the systems. About a half of the water in supply systems in the developing world is lost to leakage, illegal abstractions and vandalism. In some countries, water is highly subsidised for those connected to the system, while poorer people not connected rely on unsafe sources or expensive private sellers. Globally, 2.4 billion people lack access to adequate sanitation. In developing countries over 90% of sewage is dumped untreated into waters where the water supplies can be polluted. Recognising these problems, the World Summit on Sustainable Development in Johannesburg in 2002 set water targets to address these issues (Table 2).

Table 1 Access to water supply and sanitation. (Data are for 1999.)

RegionPopulation/millionsPercentage of population with access to:
water supplysanitation
Africa7846260
Asia36828148
Europe7289692
Latin America and the Caribbean5198376
North America309100100
Oceania308793
Total60528260

Table 2 The water targets of the World Summit on Sustainable Development 2002.

The four water targets Current state of affairs
Halve the proportion of people without access to adequate sanitation by 2021 Prioritize programmes of action to reach the sanitation and water targets Develop plans for integrated water management by 2005 Invest in water initiatives2.4 billion people don't have access to sanitation 2.2 million people die each year of water-related diseases

Even in parts of the world where there is little or no scarcity of water, environmental side-effects of water use are often becoming of great concern. This includes not only the obvious pollution, particularly of sewage, nitrates and high TDS, but also the destruction of natural wetland habitats by diversion of water elsewhere, falling water tables due to over-extraction, and the drowning of land by enormous reservoirs. About half of the rivers and lakes in Europe and North America are still seriously polluted, despite improvements in recent years. Water quality may be the biggest emerging water problem for the industrialised world.

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