Highlights from assessment activities over the past two decades, which are used to establish present and future water trends, reveal that:
Freshwater resources are unevenly distributed, with much of the water located far from human populations. Many of the world's largest river basins run through thinly populated regions. There are an estimated 263 major international river basins in the world, covering ~231 059 898 km2 or 45.3% of the Earth's land surface area (excluding Antarctica).
Groundwater represents about 90% of the world's readily available freshwater resources, and some 1.5 billion people depend upon groundwater for their drinking water.
Agricultural water use accounts for about 75% of total global consumption, mainly through crop irrigation, while industrial use accounts for about 20%, and the remaining 5% is used for domestic purposes.
It is estimated that two out of every three people will live in water-stressed areas by the year 2025. In Africa alone, it is estimated that 25 countries will be experiencing water stress (below 1,700 m3 per capita per year) by 2025. Today, 450 million people in 29 countries suffer from water shortages.
Clean water supplies and sanitation remain major problems in many parts of the world, with 20% of the global population lacking access to safe drinking water. Water-borne diseases from faecal pollution of surface waters continue to be a major cause of illness in developing countries. Polluted water is estimated to affect the health of 1.2 billion people, and contributes to the death of 15 million children annually.
A wide variety of human activities also affects the coastal and marine environment.
Population pressures, increasing demands for space and resources, and poor economic performances can all undermine the sustainable use of our oceans and coastal areas. Serious problems affecting the quality and use of these ecosystems include:
Alteration and destruction of habitats and ecosystems. Estimates show that almost 50% of the world's coasts are threatened by development-related activities.
Severe eutrophication has been discovered in several enclosed or semi-enclosed seas. It is estimated that about 80% of marine pollution originates from land-based sources and activities.
In marine fisheries, most areas are producing significantly lower yields than in the past. Substantial increases are never again likely to be recorded for global fish catches. In contrast, inland and marine aquaculture production is increasing and now contributes 30% of the total global fish yield.
Impacts of climate change may include a significant rise in the level of the world's oceans. This will cause some low-lying coastal areas to become completely submerged, and increase human vulnerability in other areas. Because they are highly dependent upon marine resources, small island developing states (SIDS) are especially vulnerable, due to both the effects of sea level rise and to changes in marine ecosystems.
Over the past decade, efforts based on Agenda 21's freshwater management guidelines in Chapter 18, which address the protection of the quality and supply of freshwater and the application of integrated approaches for the development, management and use of water resources, have focused on the following areas:
Integrated water resources development and management;
Water resources assessment;
Protection of water resources, water quality and aquatic ecosystems;
Drinking-water supply and sanitation;
Water and sustainable urban development;
Water for sustainable food production and rural development; and
The impact of climate change on water resources.
Source: Vital Water Graphics. An Overview of the State of the Worlds Fresh and Marine Waters, UNEP, Nairobi, 2002.