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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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Water withdrawal and consumption: the big gap Water withdrawal and consumption: the big gap
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...
26 Jan 2009 - by Phillipe Rekacewicz, February 2008
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Water storage capacity for selected countries Water storage capacity for selected countries
Cross-country water storage comparisons provide insights into one aspect of risk mitigation capacity. However, storage capacity is only one guide to the linkage between infrastructure and vulnerability. Countries such as Ghana and Zambia have very high levels of water storage per capita - higher, in fact, than the United States - but a limited capacity to mitigate risk. Most of the storage capacity is geared towards power generation, with a very ...
26 Jan 2009 - by Philippe Rekacewicz
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Public services provide cheaper water Public services provide cheaper water
By bringing water to people water resellers extend the coverage of piped water and provide a service with important benefits for households - but at a price. That price rises with distance from the utility, as defined by the number of intermediaries between the network and the end consumer. Having a regular supply of clean water piped into the household is the optimal type of provision for human development. Experience suggests that households w...
26 Jan 2009 - by GRID-Arendal
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World fish consumption per capita and per year World fish consumption per capita and per year
World fish consumption per year and per capita.
26 Jan 2009 - by Philippe Rekacewicz
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Total population: access to sanitation Total population: access to sanitation
The 2004 global image sadly shows that the lack of access to clean water remains a burden for the poorest countries, preventing them accelerating their development. Essentially handicapping most sub-Saharan African countries, the map shows some curious trends, such as Romania, which remains far behind all other European countries.
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique)
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Human actions leading to coastal degradation Human actions leading to coastal degradation
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...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), February 2006
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World's surface water: evaporation and runoff World's surface water: evaporation and runoff
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...
26 Jan 2009 - by Phillippe Rekacewicz (Le Monde diplomatique), February 2006
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