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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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Estimated contributions to sea-level rise (1993-2003) Estimated contributions to sea-level rise (1993-2003)
The two main reasons for sea-level rise are thermal expansion of ocean waters as they warm, and increase in the ocean mass, principally from land-based sources of ice (glaciers and ice caps, and the ice sheets of Greenland and Antarctica). Global warming from increasing greenhouse gas concentrations is a significant driver of both contributions to sea-level rise. From 1955 to 1995, ocean thermal expansion is estimated to have contributed about 0....
01 Oct 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Cumulative impacts on the marine environment Cumulative impacts on the marine environment
Climate change may, through effects on ocean currents, elevated sea temperatures, coral bleaching, shifts in marine life, ocean acidification and much more severely exacerbate the combined actions of accelerating coastal development, coastal pollution and dead zones, invasive species, bottom trawling and over-harvest. These impacts will be the strongest in 10-15% of the Worlds oceans. These areas, however, are concurrent with the most productive ...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Ratio of wastewater treatment Ratio of wastewater treatment
Sewage treatment is low or absent in many parts of the World, leading to eutrophication of the coastal zone, (toxic) algae blooms and dramatically reduce the ability of coral to recover from bleaching events dramatically. The data reflects the bodies of the UNEP Regional Seas programme.
01 Nov 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Plankton distribution changes, due to climate changes - North Sea Plankton distribution changes, due to climate changes - North Sea
With melting sea ice and warming of the oceans, marine species change their distributions, affecting entire food chains and ocean productivity. In 2005 the subtropical dinoflagellate Ceratium hexacanthum was found in CPR samples from the North Sea at levels that were 6 standard deviations above previous measurements since 1958. Further evidence of this warning signal is seen in the appearance of a Pacific planktonic plant (a diatom Neodenticula s...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Coastal regions with observations of dense shelf water flushing Coastal regions with observations of dense shelf water flushing
Knowledge and mapping of these processes is still scarce due to uneven research effort. The map shows sites with known dense shelf water cascading phenomena, which often may involve the 'flushing' effect. It is most likely that this phenomenon is also active off the coast of Alaska, Chile, Argentina and West and southern Africa and in parts of the Indian Ocean. Dense shelf water cascading is highly sensitive to increases in temperature, and hence...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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World fisheries hotspots, 2004 World fisheries hotspots, 2004
The World’s most productive fishing grounds are confined to major hotspots, less than 10% of the World oceans. The maps shows annual catch (tonnes per km2) for the World’s oceans. Notice the strong geographic concurrence of continental shelves, upwelling and primary productivity and the amount of fish caught by fisheries.
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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depth depth
About depth
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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scenario scenario
About scenario
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Distribution of coldwater and tropical coral reefs Distribution of coldwater and tropical coral reefs
Coral reefs are marine ridges or mounds, which have formed over millennia as a result of the deposition of calcium carbonate by living organisms, predominantly corals, but also a rich diversity of other organisms such as coralline algae and shellfish. The coldwater reefs are highly susceptible to deep-sea trawling and ocean acidification from climate change, which has its greatest impacts at high latitudes, while tropical reefs will become severe...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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canyondsw canyondsw
About canyondsw
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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stocks stocks
About stocks
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Climate change and tropical coral reefs, scenarios for bleaching events Climate change and tropical coral reefs, scenarios for bleaching events
Projected areas of above normal sea temperature where coral bleaching is likely to occur for the SRES A2 scenario (continuing current trends) by two different models, the PCM (1.7°C increase in 100 years) and the HadCM3 (3°C increase in 100 years) by approximately 2035 (left) and by 2055 (right). Both models project severe annual bleaching in more than 80% of the Worlds coral reefs by 2080.
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Acidification due to climate change - impacts for oceans and coral reefs Acidification due to climate change - impacts for oceans and coral reefs
As carbon concentrations in the atmosphere increase from land use changes and emissions from fossil fuels - so do concentrations in the ocean, with resultant acidification as a natural chemical process. The skeletons of coldwater coral reefs may dissolve, perhaps already within a few decades. The impacts will be greatest at high latitudes. This will have an impact on all marine organisms with calcerous shells and body parts, in addition to coral ...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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