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World ocean thermohaline circulation World ocean thermohaline circulation
The global conveyor belt thermohaline circulation is driven primarily by the formation and sinking of deep water (from around 1500m to the Antarctic bottom water overlying the bottom of the ocean) in the Norwegian Sea. When the strength of the haline forcing increases due to excess precipitation, runoff, or ice melt the conveyor belt will weaken or even shut down. The variability in the strength of the conveyor belt will lead to climate change in...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Thinning of the Arctic sea-ice Thinning of the Arctic sea-ice
Sea-ice draft is the thickness of the part of the ice that is submerged under the sea. Comparison of sea-ice draft data acquired on submarine cruises between 1993 and 1997 with similar data acquired between 1958 and 1976 indicates that the mean ice draft at the end of the melt season has decreased by about 1.3 m in most of the deep water portion of the Arctic Ocean, from 3.1 m in 1958-1976 to 1.8 m in the 1990s. In summary: ice draft in the 1990s...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Coastal issues in the islands of Comoros and Mayotte Coastal issues in the islands of Comoros and Mayotte
With poverty and high population density this group of volcanic islands between Eastern Africa and Madagascar faces challenges in the management of the coastal environment. The islands are fringed by magnificent coral reefs, and the waters houses the rare coelacanth fish. Among the responses there have been initiatives to encourage ecotourism and the support in establishing the 400 km2 Mohéli Marine Park.
23 Feb 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Population and growth, projections and historic data Population and growth, projections and historic data
The population has rapidly increased in Africa, to reach approximately 905 million inhabitants by 2005. The rate of the annual growth is levelling out after seeing a peak around 1990. Out of the sub-regions, the population is fairly evenly distributed, as indicated in the pie-chart, with Central Africa trailing behind the others, and the Western Indian Ocean islands with the smallest share out of the total population.
02 Nov 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Caspian Sea - salinity Caspian Sea - salinity
The Caspian Sea has internal drainage, which means that it does not have an outlet to the World Ocean. All water entering the sea accumulates or evaporates. The sea surface salinity in the sea exhibits a gradient, with the semi-encludes bay of Kara-Bogaz-Gol having the most saline water. This bay was closed between 1980 and 1992.
07 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Overview of renewable energy sources Overview of renewable energy sources
This chart shows eight different sources of renewable energy and explains advantages and drawbacks of each - wind, sun (photovoltaic and thermal), geothermal, wood, ocean, waste, water (hydroelectricity).
17 May 2005 - by UNEP/GRID-Arendal
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Climate change vulnerability in Africa Climate change vulnerability in Africa
Multiple stresses make most of Africa highly vulnerable to environmental changes, and climate change is likely to increase this vulnerability. This graphic shows which of the regions of Africa (North Africa, West Africa, Central Africa, East Africa, Southern Africa and the Western Indian Ocean Islands) are most vulnerable to specific impacts of climate change. These impacts include desertification, sea level rise, reduced freshwater availability,...
17 May 2005 - by Delphine Digout, Revised by Hugo Ahlenius, UNEP/GRID-Arendal
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Carbon cycle Carbon cycle
Carbon is the basis of all organic substances, from fossil fuels to human cells. On Earth, carbon is continually on the move – cycling through living things, the land, ocean, atmosphere. What happens when humans start driving the carbon cycle? We have seen that we can make a serious impact – rapidly raising the level of carbon in the atmosphere. But we really have no idea what we are doing. At the moment we don’t even know what happens to all the...
17 May 2005 - by UNEP/GRID-Arendal
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Temperature trends (1976 - 2000) Temperature trends (1976 - 2000)
Over the 20th century there has been a consistent, large-scale warming of both the land and ocean surface, with largest increases in temperature over the midand high latitudes of northern continents. This graphic shows the temperature changes across the planet from the years 1976 to 2000, as long-term deviations from the expected mean. The higher temperature increases over land surface - compared to ocean surface - is consistent with the observed...
17 May 2005 - by UNEP/GRID-Arendal
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Climate change vulnerability in Africa Climate change vulnerability in Africa
Multiple stresses make most of Africa highly vulnerable to environmental changes, and climate change is likely to increase this vulnerability. This graphic shows which of the regions of Africa (North Africa, West Africa, Central Africa, East Africa, Southern Africa and the Western Indian Ocean Islands) are most vulnerable to specific impacts of climate change. These impacts include desertification, sea level rise, reduced freshwater availability,...
20 Sep 2005 - by Delphine Digout, Revised by Hugo Ahlenius, UNEP/GRID-Arendal
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Nenets Autonomous Okrug, reference map Nenets Autonomous Okrug, reference map
Nenets Autonomous Okrug is an administrative region in Arctic Northwest Russia, covering some 176000 sq km of tundra and marshland. The capital city of the region is Narian-Mar. Off the coast are parts of the Arctic ocean know as Barents and Kara seas, and the long island in the north west is Novaya Zemlya.
07 Oct 2005 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Arctic, topography and bathymetry (topographic map) Arctic, topography and bathymetry (topographic map)
The Arctic represents the northermost area of the World, the Arctic Ocean and the land areas that surrounds it. The region is characterized but cold temperatures, and ice and snow. The summers are short, but with long periods of daylight (midnight sun). The winters are long and cold and with periods with no sun (polar night). The Arctic Ocean is one basin that is mostly covered by sea ice, and is connected to the Pacific and Atlantic Oceans. The ...
01 Oct 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Arctic sea routes - Northern sea route and Northwest passage Arctic sea routes - Northern sea route and Northwest passage
Sea routes along the edges of the Arctic ocean, or rather along the coasts of Northern Canada and Russia, holds potential for decreasing the number of days in shipping goods from the Pacific to Atlantic coasts in Europe and North America, and vice versa. In addition, this could provide a means to transport natural resources, such as oil and gas, extracted in the Arctic. Currently these routes have not been possible to use this, due to the ice con...
07 Oct 2005 - by Hugo Ahlenius, 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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Barents Sea ecoregion conservation priority areas and oil and gas infrastructure Barents Sea ecoregion conservation priority areas and oil and gas infrastructure
The Barents Sea ecoregion - the part of the World Ocean north of the Nordic countries and Northwest Russia, has a unique environment with major sea bird colonies, rich benthic and plankton fauna and many major sea mammal species. To identify priority areas for conservation, thirty experts delineated sea areas based on ecological criteria in a WWF study. One of the main threats to the region is the development associated with the expansion of foss...
06 Dec 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Protected areas in the Barents ecoregion Protected areas in the Barents ecoregion
The Barents Sea ecoregion - the part of the World Ocean north of the Nordic countries and Northwest Russia, has a unique environment with major sea bird colonies, rich benthic and plankton fauna and many major sea mammal species. Within this ecoregion, this graphic illustrates the existing coverage of protected areas. One of the main threats to the region is the development associated with the expansion of fossil fuel extraction activities. Russi...
06 Dec 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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Albedo of basic thick sea ice surface types Albedo of basic thick sea ice surface types
The albedo for different surface conditions on the sea ice range widely, from roughly 85 per cent of radiation reflected for snow-covered ice to 7 per cent for open water. These two surfaces cover the range from the largest to the smallest albedo on earth. Melting snow, bare ice and ponded ice lie within this range. There is a general decrease in the albedo of the ice cover during the melt season as the snow-covered ice is replaced by a mix of me...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Change in the age of ice on the Arctic Ocean, comparing September ice ages in 1988, 1990, 2001 and 2005 Change in the age of ice on the Arctic Ocean, comparing September ice ages in 1988, 1990, 2001 and 2005
The age of sea ice in the Arctic is changing, and not only the extent and concentrations. Studies show that in recent years there is a higher proportion of younger ice to older ice than was observed in the late 1980s. This analysis is based on results from a simulation using drifting buoy data and satellite-derived ice-concentration data. The darker the colour, the older the ice.
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Ice sheets, schematic illustration for Greenland and Antarctica Ice sheets, schematic illustration for Greenland and Antarctica
The ice cover in Greenland and Antarctica has two components – thick, grounded, inland ice that rests on a more or less solid bed, and thinner floating ice shelves and glacier tongues. An ice sheet is actually a giant glacier, and like most glaciers it is nourished by the continual accumulation of snow on its surface. As successive layers of snow build up, the layers beneath are gradually compressed into solid ice. Snow input is balanced by glaci...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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