HomeAboutActivitiesMapsPhotosPublicationsNews
 
Home >> Ocean

Tag: Ocean

Nitrogen sources to watershed exports to the oceans Nitrogen sources to watershed exports to the oceans
Over the last 20 years, significant data and experience in understanding and addressing the sectoral drivers, pressures, sources, impacts and response to reactive nitrogen have been gathered and progress made in trying to address these issues. The key sectors that are involved include the agriculture, waste-water management, and fertilizer production sectors. As shown in the figure for the year 2000, models indicate that globally, roughly equal a...
16 Oct 2013 - by GRID-Arendal
3
Dead zones and fertilizers Dead zones and fertilizers
The production and use of reactive nitrogen based artificial fertilizers has had huge global benefits providing food for billions through the green revolution. The down side of the increased availability of cheap manufactured nitrogen fertilizer products has been global environment problems associated with excess nutrients, specifically the problems of eutrophication, coastal hypoxic zones and nitrate contaminated groundwater. Tracing the format...
16 Oct 2013 - by GRID-Arendal
4
Development in Offshore wind capacity Development in Offshore wind capacity
Offshore wind, currently around 3 000 MW, has mainly been concentrated in northern European countries, around the North Sea and the Baltic Sea. Europe’s leadership is primarily attributed to public policy and a thriving wind energy industry. EU legislation mandates significant reductions of carbon emission, requiring, among other measures, greater usage of renewable energy resources. As of 2011, around 69 wind farms were installed or under const...
16 Oct 2013 - by GRID-Arendal
3
Spots of potential for wave energy harvest Spots of potential for wave energy harvest
Wave energy is captured directly from surface waves or from pressure fluctuations below the ocean surface. Wave power varies considerably in different parts of the world, making it more economically feasible to harness in some parts than in others, hence making wave energy a region-specific energy source. For example, strong winds variations are observed within the band between 30 and 60 degrees latitude, and circumpolar storms near the southern...
16 Oct 2013 - by GRID-Arendal
5
Looking further offshore and in deeper waters Looking further offshore and in deeper waters
The high capital cost of offshore foundations bounds offshore wind energy to near shore locations. Most of the capacity has been installed in relatively shallow waters (under 20 m deep) no more than 20 km from the coast in order to minimize the extra costs of foundations and sea cables (EWEA, 2009). Most of the recently added capacity is installed in water depths of up 40 metres, as far as 60 kilometres off the coast, as shown in the figure.
16 Oct 2013 - by GRID-Arendal
3
Estimated ecosystem services value Estimated ecosystem services value
Marine ecosystem services have substantial economic value. While exact figures are still debated, attempts to estimate the value of coastal ecosystem services have found such values to be on the order of trillions of US dollars annually (Costanza, et al., 1997). Nearly three-quarters of this value resides in coastal zones (Martínez, et al., 2007). These ecosystem services offer a renewable opportunity to meet basic human needs, support a healthy...
15 Oct 2013 - by GRID-Arendal
5
World oceans, a cornucopia of goods and services World oceans, a cornucopia of goods and services
Throughout the course of history, humans have been drawn to coastal areas to enjoy the bounty of the sea. As much as 40 per cent of the world’s population now lives within 100 kilometres of the shoreline (Martínez, et al., 2007) and this population continues to grow – increasing our reliance and impact on the ocean and coast. Two thirds of the world’s megacities are on the coast.
15 Oct 2013 - by GRID-Arendal
5
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
4
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
4
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
3
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
3
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
2
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
3
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
2
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
3
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
4
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
3
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
4
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
3
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
2
      1 2 3 4 5 6 7 | Next