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Increased global water stress Increased global water stress
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...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), February 2006
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Relative demographic weight for each continent Relative demographic weight for each continent
Population percentage increase by continent.
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique)
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Poor and rich: inequal demographic evolution Poor and rich: inequal demographic evolution
According to the medium hypothesis of the United Nations, a projection comparing the population in developed and undeveloped countries.
26 Jan 2009 - by GRID-Arendal
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Fishing yield Fishing yield
Three-quarters of the world’s fish stocks are currently exploited to the maximum extent, if not in excess (FAO, 2000). This exploitation has had the following impacts: - A growing variety of fishery products are being exploited. Commercial fishermen are targeting progressively smaller species at lower levels of the food chain because the main predator species are being depleted. - Most of the world’s main fishing areas are close to full exploit...
26 Jan 2009 - by Phillippe Rekacewicz, February 2006
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The water cycle The water cycle
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...
01 Feb 2008 - by Philippe Rekacewicz , UNEP/GRID-Arendal
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Water - cooperation or conflict? Water - cooperation or conflict?
History shows that conflicts over water often emerge and give rise to political tensions, but that most disputes are resolved peacefully. However, the absence of conflict is, at best, only a partial indicator of the depth of cooperation. Measuring the level of conflict between governments over water is inherently difficult as water is seldom a stand-alone foreign policy issue. Oregon State University has attempted to compile data covering every r...
26 Jan 2009 - by GRID-Arendal
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Freshwater use by sector at the beginning of the 2000s Freshwater use by sector at the beginning of the 2000s
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...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique)
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The disappearance of the Aral Sea The disappearance of the Aral Sea
The demise of the Aral Sea in central Asia was caused primarily by the diversion of the inflowing Amu Dar’ya and Syr Dar’ya rivers to provide irrigation water for local croplands. These diversions dramatically reduced the river inflows, causing the Aral Sea to shrink by more than 50%, to lose two-thirds of its volume, and to greatly increase its salinity. At the current rate of decline, the Aral Sea has the potential to disappear completely by 20...
26 Jan 2009 - by GRIDA
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Nitrate levels: concentrations at river mouths Nitrate levels: concentrations at river mouths
Nutrients are essential to life. In aquatic systems, nitrogen and phosphorus are the two nutrients that most commonly control the growth of aquatic plants, algae and bacteria. Nitrogen and phosphorus are considered to be the primary drivers of eutrophication of aquatic ecosystems, where increased nutrient concentrations lead to increased primary productivity. Some systems are naturally eutrophic, whereas others have become eutrophic as a result o...
26 Jan 2009 - by Philippe Rekacewicz
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Tigris and Euphrates rivers fragmentation Tigris and Euphrates rivers fragmentation
It has been predicted that access to water will create conflict between countries. In Africa, central Asia, west Asia and the Americas, some countries are already arguing fiercely over access to rivers and inland seas, and confrontations could arise as water shortages grow (Gleick, 2000). Countries currently or potentially involved in international disputes over access to river water and aquifers include: - Turkey, Syria and Iraq (the Tigris and...
26 Jan 2009 - by Philippe Rekacewicz
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State of world fisheries and aquaculture State of world fisheries and aquaculture
Drawing on research and statistical data since 2000, experts at the University of British Columbia in Vancouver have shown that catches reported by China are largely overestimated, concealing a substantial decline in world catches since the middle of the 1980s.
26 Jan 2009 - by Philippe Rekacewicz
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Benefits of marine and coastal ecosystems to human wellbeing Benefits of marine and coastal ecosystems to human wellbeing
Besides the well-known economic value of fisheries, there are several other activities generating significant revenues in coastal and marine areas. Tourism has become one of the world’s fastest growing industries, providing a significant proportion of the GDPs of many developing countries. Small island states are particularly reliant on coastal and marine tourism. In the Caribbean, for example, the industry accounts for a quarter of the total eco...
26 Jan 2009 - by Phillippe Rekacewicz, February 2006
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Level of river fragmentation and flow regulation Level of river fragmentation and flow regulation
River fragmentation - The interruption of a river’s natural flow by dams, inter-basin transfers or water withdrawal - is an indicator of the degree to which rivers have been modified by man (Ward and Stanford, 1989, and Dynesius and Nilsson, 1994, as cited in Revenga et al., 2000). A fragmentation analysis carried out by the University of Umea and the World Resources Institute showed that, of 227 rivers assessed, 37% were strongly affected by fra...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), March 2006
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Increasing price with volume Increasing price with volume
Rising block tariffs aim to achieve several public policy goals. A low or zero tariff applied to the first block can enhance affordability. For example, Durban, South Africa, provides 25 litres of water a day free of charge - a lifeline to many - with a steep increase above this level. Higher tiers aim at enabling utilities to increase efficiency, by creating disincentives for overuse, and at mobilizing revenues to cover costs. Block tariffs thus...
26 Jan 2009 - by GRID-Arendal
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Water supply per river basin in 1995 and 2025 Water supply per river basin in 1995 and 2025
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.
26 Jan 2009 - by Philippe Rekacewicz,February 2006
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Fish diversity in freshwater systems Fish diversity in freshwater systems
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....
26 Jan 2009 - by Philippe Rekacewicz
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Cereal productivity in sub-Saharan Africa under a projected Intergovernamental Panel on Climate Change (IPCC) scenario Cereal productivity in sub-Saharan Africa under a projected Intergovernamental Panel on Climate Change (IPCC) scenario
A majority of the population in sub-Saharan African lives in rural areas, where income and employment depend almost entirely on rain-fed agriculture. This population is today at high risk. Sub-Saharan Africa already has a highly variable and unpredictable climate and is acutely vulnerable to floods and droughts. A third of the people in the region live in drought-prone areas, and floods are a recurrent threat in several countries. With climate ch...
26 Jan 2009 - by Philippe Rekacewicz
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The spread of cholera 1950-2004 The spread of cholera 1950-2004
Increasing floods in between dry periods represent ideal conditions for spreading diseases such as cholera. In Nouakchott, the capital of Mauritania located in the desert, precipitations - when they occur - are always accompanied by a cholera epidemic, especially in poor areas where waste matter is not managed. Cholera had almost disappeared globally by the mid 1950s, but it reappeared and spread throughout the world during the last few decades. ...
26 Jan 2009 - by GRID-Arendal
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More water evaporates from reservoirs than is consumed by humans More water evaporates from reservoirs than is consumed by humans
Throughout the 20th century, global water use has increased in the agricultural, domestic and industrial sectors. Evaporation from reservoirs has increased at a slower rate. Projections indicate that both global water use and evaporation will continue to increase.
26 Jan 2009 - by Philippe Rekacewicz)
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Freshwater alkalinity: 1976-2008 Freshwater alkalinity: 1976-2008
Alkalinity is commonly used to indicate a water body’s capacity to buffer against acidity; that is, the ability to resist, or dampen, changes in pH. Thus, alkaline compounds in water, such as bicarbonates, carbonates, and hydroxides, lower the acidity of the water and increase the pH. Alkalinity (as CaCO3) was analysed for all sampling stations available at the continental level. Concentrations remained reasonably steady between the two decades ...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), February 2006
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