Nutrient loading is projected to become an increasingly severe problem, particularly in developing countries. Nutrient loading already has major adverse effects on freshwater ecosystems and coastal regions in both industrial and developing countries.

Agriculture already consumes 70% of all global freshwater withdrawn worldwide and has depleted soil nutrients, resulting in N, P and K deficiencies covering 59%, 85%, and 90% of harvested area respectively in the year 2000 coupled with a 1,136 million Mg yr loss of total global production.

Population by region was calculated averaging the results forecasted by the scenarios of the GEO-4 report using the WaterGAP modeling.

Water is the life force of our planet, but only 1 per cent of all the freshwater on Earth is available for human use.

The Arctic char species complex, sensu stricto, represent a key component of the marine and freshwater ecosystems of the north. Chars are stressed by factors such as fisheries, climate change and pollutants. We are possibly altering char biodiversity without documenting it and understanding its relevance. Concerted pan-Arctic biodiversity assessments, sustained research, and coordinated monitoring of chars are required to outline the scope of div...

The water supply situation in Africa is already precarious, and climate change is expected to exacerbate the problem. This graphic shows the amount of water supply coverage at the national level for Africa, and the amount of sanitation coverage, as a percentage, at the national level for Africa. Statistics are shown for rural areas, for urban areas, and for all areas.

The potential impacts of sea level rise on the Nile Delta are expected to include a decline in water quality that would affect freshwater fish, the flooding of agricultural land and damage to infrastructure. This graphic shows the Nile Delta region as it is today (2002), the area as it would appear with a 0.5 m sea level rise, and the area as it would appear with a 1.0 m sea level rise.

Straddling the borders of Nigeria, Chad, Niger and Cameroon in West Africa, Lake Chad has been a source of freshwater for irrigation projects in all these countries. This graphic traces the shrinkage of Lake Chad and changes in vegetation from 1963 to 2001. It includes maps of the lake from 1963, 1973, 1987, 1997 and 2001. Climatic changes and high demands for agricultural water are responsible for the lake's shrinkage.

Starting in Bangladesh with a few watersheds, going up to the world. Fisheries and freshwater management (wetlands).

Straddling the borders of Nigeria, Chad, Niger and Cameroon in West Africa, Lake Chad has been a source of freshwater for irrigation projects in all these countries. This graphic traces the shrinkage of Lake Chad and changes in vegetation from 1963 to 2001. It includes maps of the lake from 1963, 1973, 1987, 1997 and 2001. Climatic changes and high demands for agricultural water are responsible for the lake's shrinkage.

It is estimated that water pollution denies close to 1.3 billion people (20% of the global population in 2000) access to clean water supplies. In 1986, WHO reported that there were 250 million new cases of waterborne diseases each year, causing the deaths of nearly 3.5 million people. An estimated 4.2 billion cases of waterborne diseases are reported each year, with diarrhoea accounting for 4 billion of the total (Cosgrove and Rijsberman, 2000; R...

According to Population Action International, based upon the UN Medium Population Projections of 1998, more than 2.8 billion people in 48 countries will face water stress, or scarcity conditions by 2025. Of these countries, 40 are in West Asia, North Africa or sub-Saharan Africa. Over the next two decades, population increases and growing demands are projected to push all the West Asian countries into water scarcity conditions. By 2050, the numbe...

Environment water transport system. The water cycle consists of precipitation, vapour transport, evaporation, evapo-transpiration, infiltration, groundwater flow and runoff. Figure 1 explains the global water cycle, illustrating how nearly 577,000 km3 of water circulates through the cycle each year. A table of estimated residence times shows the approximate times that water resources exist as biospheric water, atmospheric water and so on. The w...

The agricultural sector is by far the biggest user of freshwater. Analysis indicates that: - In the United States, agriculture accounts for some 49% of total freshwater use, with 80% of this volume being used for irrigation (Shiklomanov, 1999). - In Africa and Asia, an estimated 85-90% of all freshwater used is for agriculture (Shiklomanov, 1999). - According to estimates for the year 2000, agriculture accounted for 67% of the world’s total fr...

Although the absolute quantities of freshwater on earth have always remained approximately the same, the uneven distribution of water and human settlement continues to create growing problems freshwater availability and accessibility.

Although freshwater ecosystems such as rivers, lakes and wetlands occupy less than 2% of the earth’s total land surface, they provide a wide range of habitats for a significant proportion of the world’s plant and animal species. Many are yet to be discovered, but the number of freshwater species worldwide is estimated at between 9,000 and 25,000 (Cosgrove and Rijsberman, 2000). However, this number is rapidly decreasing due to human interference....

Freshwater use by continents is partly based on several socio-economic development factors, including population, physiographic, and climatic characteristics. Analysis indicates that: - Annual global freshwater withdrawal has grown from 3,790 km3 (of which consumption accounted for 2,070 km3 or 61%) in 1995, to 4,430 km3 (of which consumption accounted for 2,304 km3 or 52%) in 2000 (Shiklomanov, 1999). - In 2000, about 57% of the world’s freshw...

Physical alteration and the destruction of habitats are now considered one of the most significant threats to coastal areas. Half of the world’s wetlands, and even more of its mangrove forests, have been lost over the past century to physical alterations, the major causes being accelerating social and economic development and poor-planning (UNEP, 2002). There are currently about one billion people living in coastal urban areas. It is estimated t...

Because much of the world’s surface water is far from concentrations of human settlements, not all of it is readily usable. Some facts concerning global freshwater concentrations: - It is estimated that the freshwater available for human consumption varies between 12,500 km3 and 14,000 km3 each year (Hinrichsen et al., 1998; Jackson et al., 2001). - Many countries in Africa, the Middle East, western Asia, and some eastern European countries ha...

The Mekong River - survival for millions Following the course of the Mekong River helps to understand the human/river hydrological interdependence. From its source on the Tibetan Plateau it drops 5,000 metres and flows across six countries before reaching its delta. More than a third of the population of Cambodia, Lao PDR, Thailand and Vietnam - some 60 million people - live in the Lower Mekong Basin, using the river for drinking water, food, ir...