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Transboundary river basins of the Balkans, overview Transboundary river basins of the Balkans, overview
Prior to 1992, there were only six transboundary river basins in the Balkans, but after the break-up of former Yugoslavia, the number more than doubled. There are now 13 internationally shared river basins and four trans-boundary lake basins. Such a fragmented situation means that new international legal regimes specifically for water basins need to be worked out. Talks between the countries concerned are also essential to develop future policies...
30 Nov 2007 - by Philippe Rekacewicz, Stephane Kluser, Matthias Beilstein, Ieva Rucevska, Cecile Marin, Otto Simonett
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Major river basins of Africa Major river basins of Africa
This map shows the locations of 13 major river basins in Africa: the Senegal, Volta, Niger, Lake Chad, Nile, Lake Turkana, Juba Shibeli, Ogooue, Congo, Zambezi, Okavango, Limpopo and Orange river basins.
17 May 2005 - by Philippe Rekacewicz, Delphine Digout, UNEP/GRID-Arendal
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Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001 Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001
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.
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Mine and industrial site in Koshkar-Ata, Kazakhstan Mine and industrial site in Koshkar-Ata, Kazakhstan
Much of the area near Koshkar-Ata Lake in Kazakhstan, just off the shore of the Caspian Sea, has been severely polluted due to mining activities of uranium phosphate. The area is also affected from chemical plants and metallurgic industries. The pollutants are quickly making there way to the Caspian Sea.
29 Nov 2007 - by Viktor Novikov, UNEP/GRID-Arendal
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Variations in sea level for the Caspian Sea (1840-2004) Variations in sea level for the Caspian Sea (1840-2004)
The Caspian Sea has been endoreic – inwardly draining, without any outlet – since the Pliocene epoch (about 5 million years ago), prompting some specialists to treat it as the world’s largest lake. Studies of its geomorphology and hydrology have revealed alternating cycles of rising and falling water levels, raising many questions, scientific for some, more down-to-earth for those living on the shores.
07 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Export of fisheries products in Africa Export of fisheries products in Africa
For some African countries, particularly in West-Africa and to lesser extent also countries along the Indian Ocean, fisheries contribute significantly to exports. Remarkable is also that the fish sector is important for a landlocked country like Uganda bordering Victoria Lake.
02 Nov 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
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The Cryosphere, components and world maps The Cryosphere, components and world maps
Snow and the various forms of ice - the cryosphere - play different roles within the climate system. The two continental ice sheets of Antarctica and Greenland actively influence the global climate over time scales of millennia to millions of years, but may also have more rapid effects on, for example, sea level. Snow and sea ice, with their large areas but relatively small volumes, are connected to key interactions and feedbacks at global scales...
01 Oct 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Formation of lakes and glacier lake outburst floods (GLOFs) by Medvezhi Glacier, Pamirs Formation of lakes and glacier lake outburst floods (GLOFs) by Medvezhi Glacier, Pamirs
The increasing number of glacial and moraine lakes in Central Asian mountains is a matter of great concern. One of the surging glaciers that poses a potential threat is the 15 km long Medvezhi (Bear) Glacier in the Pamirs mountains of Tajikistan. Its surges have repeatedly caused lake formation, outburst and subsequent floodings. In 1963 and 1973, the surge of the glacier was so significant (1 to 2 km increase in length) that the ice dam exceeded...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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The Cryosphere, world map The Cryosphere, world map
Snow and the various forms of ice - the cryosphere - play different roles within the climate system. The two continental ice sheets of Antarctica and Greenland actively influence the global climate over time scales of millennia to millions of years, but may also have more rapid effects on, for example, sea level. Snow and sea ice, with their large areas but relatively small volumes, are connected to key interactions and feedbacks at global scales...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Variations in snow depth and ice cover, alpine lake at Hardangervidda plateau, Norway Variations in snow depth and ice cover, alpine lake at Hardangervidda plateau, Norway
Climate warming means that lowland lakes typically are experiencing longer ice-free periods, promoting greater biological productivity. However, despite this warming trend, biological productivity may be reduced, at least temporarily, in alpine areas with increased winter precipitation. During years with high winter precipitation in alpine areas of western Norway, in spite of higher temperatures, fish growth and recruitment were lower than in low...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Arctic delta pond ecosystems, seasonal flooding and adaptation Arctic delta pond ecosystems, seasonal flooding and adaptation
The physical development and ecosystem health of river deltas in cold regions are strongly controlled by ice processes and thus are highly susceptible to the effects of climate change. As an example, the photograph shows a typical lake/pond and river network in the Peace-Athabasca Delta (Canada), one of the largest freshwater deltas in the world. The water budget and sediment-nutrient supply for the multitude of lakes and ponds that dot the ripar...
01 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Trends in spring temperatures and ice break-up dates in Canada Trends in spring temperatures and ice break-up dates in Canada
In Canada, recent evidence indicates a shortening of the freshwater-ice season over much of the country with the reduction being mainly attributable to earlier break ups. These trends match those in surface air temperature during the last 50 years. For example, similar spatial and temporal patterns have been found between trends (1966 to 1995) in autumn and spring 0°C isotherms (lines on a map showing location of 0°C air temperatures) and lake fr...
01 Oct 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Forest vs. Agriculture – the case of the Mabira forest reserve, Uganda Forest vs. Agriculture – the case of the Mabira forest reserve, Uganda
The Mabira forest reserve, on the shores of Lake Victoria hosts valuable wildlife, serves as a timber resource, provides ecosystem services for the water balance and the rainforests represents a tourist destination. Following a proposed plan for clearing a third of the reserve for agricultural use, the values of the forest were calculated by local researchers. This economic evaluation of the forest shows that from a short-term perspective, growin...
12 May 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
2
Disappearing lakes - Old Crow Basin, Canada (1951-2001) Disappearing lakes - Old Crow Basin, Canada (1951-2001)
The Arctic contains a variety of types of lakes but overall, it is thermokarst lakes and ponds that are the most abundant and productive aquatic ecosystems in the Arctic. They are found extensively in the lowland regions of western and northern Alaska, Canada and Siberia. These (i.e., thaw) lakes are most commonly formed by the thaw of ice-rich permafrost, which leads to the collapse of ground levels and ponding of surface water in the depression...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
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Trends in lakes in the Arctic Trends in lakes in the Arctic
The Arctic contains a variety of types of lakes but overall, it is thermokarst lakes and ponds that are the most abundant and productive aquatic ecosystems in the Arctic. They are found extensively in the lowland regions of western and northern Alaska, Canada and Siberia. These (i.e., thaw) lakes are most commonly formed by the thaw of ice-rich permafrost, which leads to the collapse of ground levels and ponding of surface water in the depression...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Disappearing Arctic lakes - examples in Siberian lakes, 1973 to 1997 Disappearing Arctic lakes - examples in Siberian lakes, 1973 to 1997
The Arctic contains a variety of types of lakes but overall, it is thermokarst lakes and ponds that are the most abundant and productive aquatic ecosystems in the Arctic. They are found extensively in the lowland regions of western and northern Alaska, Canada and Siberia. These (i.e., thaw) lakes are most commonly formed by the thaw of ice-rich permafrost, which leads to the collapse of ground levels and ponding of surface water in the depression...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001 Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001
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.
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
3
Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001 Lake Chad - decrease in area 1963, 1973, 1987, 1997 and 2001
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.
11 Jul 2006 - by Philippe Rekacewicz and Hugo Ahlenius UNEP/GRID-Arendal
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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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The Mekong River - survival for millions The Mekong River - survival for millions
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...
26 Jan 2009 - by Philippe Rekacewicz
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