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Tag: Ocean

Global Ocean Acidification Global Ocean Acidification
As carbon concentrations in the atmosphere increase, so do concentrations in the ocean, with resultant acidification as a natural chemical process.
06 Oct 2009 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Larimichthys polyactis Catch in early 2000s and predicted Catch Shift Larimichthys polyactis Catch in early 2000s and predicted Catch Shift
(a) Current (early 2000s) and (b) climate-shifted distributions of the small yellow croaker Larimichthys polyactis (Sciaenidae). The climate-shifted distribution was predicted by a dynamic bioclimate envelope model described by Cheung et al. (2008), under a hypothetical increase in average global ocean temperature of 2.5°C. Boundaries of Exclusive Economic Zones are delineated by the dashed lines.
06 Oct 2009 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Climate feedbacks - the connectivity of the positive ice/snow albedo feedback, terrestrial snow and vegetation feedbacks and the negative cloud/radiation feedback Climate feedbacks - the connectivity of the positive ice/snow albedo feedback, terrestrial snow and vegetation feedbacks and the negative cloud/radiation feedback
Feedback refers to the modification of a process by changes resulting from the process itself. Positive feedbacks accelerate the process, while negative feedbacks slow it down. Part of the uncertainty around future climates relates to important feedbacks between different parts of the climate system: air temperatures, ice and snow albedo (reflection of the sun’s rays), and clouds. An important positive feedback is the ice and snow albedo feedback...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Thermohaline Circulation Thermohaline Circulation
If the large-scale ocean circulation is disturbed by processes altering heat and salinity in the Arctic Ocean, the consequences may be felt worldwide. The mechanism involved is the world-encompassing meridional overturning circulation (MOC).
27 Oct 2009 - by Laura Margueritte
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Uptake of Carbon Dioxide from the Atmosphere Uptake of Carbon Dioxide from the Atmosphere
Arctic marine systems currently provide a substantial carbon sink but the continuation of this service depends critically on arctic climate change impacts on ice, freshwater inputs, and ocean acidification.
27 Oct 2009 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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World ocean thermohaline circulation (alternative version) World ocean thermohaline circulation (alternative version)
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...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Greenland, showing rates of surface-elevation change between the late 1990s and 2003 Greenland, showing rates of surface-elevation change between the late 1990s and 2003
Mass-balance estimates for Greenland show thickening at high elevations since the early 1990s at rates that increased to about 4 cm per year after 2000, consistent with expectations of increasing snowfall in a warming climate. However, this mass gain is far exceeded by losses associated with large increases in thinning of the ice sheet near the coast. Total loss from the ice sheet more than doubled, from a few tens of billions of tonnes per year ...
18 Apr 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Barents Sea ecoregion conservation priority areas Barents Sea ecoregion conservation priority areas
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.
06 Dec 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Ocean currents and sea ice extent Ocean currents and sea ice extent
Arctic Ocean circulate in a large clockwise rotational pattern moving from east to west around the polar ice cap. This rotating pattern, known as a gyre, occurs as a result of the clockwise winds that typically occur in this region. The Barents region is affected by this and the ice edge extent in the Arctic.
04 Oct 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Reference map for the city of Malindi, Kenya Reference map for the city of Malindi, Kenya
This map locates the city of Malindi (population approximatly 150 000 inhabitants) in Kenya. The city is located on the Kenyan coast, on the Indian Ocean. The map also displays a world map for further reference, as well as other reference points, such as the location of Nairobi and Mombasa.
20 Sep 2005 - by Hugo Ahlenius, 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, UNEP/GRID-Arendal
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Sea level rise: Costa Rica coastal communities under threat Sea level rise: Costa Rica coastal communities under threat
Sea level rise is an important indicator of climate change. A rise in sea level may result in flooding, salinisation of fresh water, coastal erosion and in some cases loss of land to the ocean. As depicted, some coastal communities in Costa Rica are particularly vulnerable to sea level rise.
17 May 2005 - by UNEP/GRID-Arendal
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ENSO Variability index ENSO Variability index
Variability in the El Nino Southern Oscillation (ENSO) index 1982-2004, and temperature variation for those years - plus or minus 3 degrees maximum in those years of the ENSO events in the Pacific Ocean and affected region.
17 May 2005 - by Viktor Novikov, UNEP/GRID-Arendal
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Intense hurricanes in the Atlantic Basin Intense hurricanes in the Atlantic Basin
Global average temperature increased by 0.6 ° C over the last century, while sea levels rose by 9 to 20 cm. The IPCC projects increases in the global average surface temperature by between 1.4°C and 5.8°C and in sea level by between 9 and 88 cm. Sea level rise in combination with hurricane landfalls presents one of the greatest climate-related hazards in tropical Latin America. From 1945 to 1990 there had been an overall decrease in the number ...
17 May 2005 - by UNEP/GRID-Arendal
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Major River Systems in the Arctic Major River Systems in the Arctic
The Arctic has several of the world’s largest rivers.This graphic shows the major river systems of the Arctic and their annual discharges in cubic kilometres, and the catchment area of the Arctic Ocean. The major river systems shown are the Mackenzie, Yukon, Nelson, Kolyma, Indigirka, Lena, Kotya, Yenisey, Ob, Pechora, Severnyy and Dvina.
28 Sep 2005 - by CAFF (Conservation of Arctic Flora and Fauna); see source field
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Piscivore-zooplanktivore Index Piscivore-zooplanktivore Index
Shows the Piscivore-zooplanktivore ratio between the years 1950-1995, in the Northeast Atlantic Ocean, and their relationship in the trophic composition of the ecosystem, which shows an ondulating trend, which has decreased in the time period.
28 Sep 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Coral reefs at risk from human activities Coral reefs at risk from human activities
Population growth and technology: operating together these two factors account for the major causes of coral reef decline - excessive domestic and agricultural waste pouring into ocean waters, poor land-use practices that increase sedimentation of rivers and then of reefs, and over-exploitation of reef resources, often in combination with practices such as harvesting with dynamite and poison, all degrade reefs.
28 Sep 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Arctic pelagic food web Arctic pelagic food web
The marine animal food chain is very complex and multilayered as are most food chains. This is a quick reference to represent the complete food chain in regards to pelagic crustaceans and invertebrates.
28 Sep 2005 - by UNEP/GRID-Arendal
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The Antarctic convergence The Antarctic convergence
The Antarctic convergence represents an important climatic boundary between air and water masses, and is also an approximate boundary for the Southern Ocean, surrounding the Antarctic continent. The water around the land mass is cold and with a slightly lower salinity than north of the convergence zone. The area is also rich in nutrients, providing a key support for the ecosystems in the Southern Ocean.
28 Sep 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Sites with dead zones (oxygen depletion on the sea bottom) Sites with dead zones (oxygen depletion on the sea bottom)
Dead zones (hypoxic i.e. oxygen deficient water) in the coastal zones are increasing, typically surrounding major industrial and agricultural centers. This is commonly occuring due to nutrient pollution, in the form of nitrogen and phosphorous leading to algal blooms and eutrophication
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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