HomeAboutActivitiesMapsPhotosPublicationsNews
 
Home >> Ice

Tag: Ice

Time series of freeze-up and break-up dates from selected Northern Hemisphere lakes and rivers, 1846–1995 Time series of freeze-up and break-up dates from selected Northern Hemisphere lakes and rivers, 1846–1995
Limited by the availability of detailed observations, most historical evaluations of changes in freshwater ice have focused on relatively simple characteristics, such as the timing of autumn freeze up and spring break up, and maximum ice-cover thickness. Based on 27 long-term (about 150-year) records from around the Northern Hemisphere, Magnuson and others (Figure 8.1) discovered that freeze up has been delayed by approximately six days per hundr...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Distribution and current trend of polar bear subpopulations throughout the circumpolar Arctic Distribution and current trend of polar bear subpopulations throughout the circumpolar Arctic
Polar bears occur in 19 relatively discrete subpopulations with an estimated worldwide abundance of 20,000– 25,000 animals. Our knowledge of the status and trend of each subpopulation varies due to availability, reliability, and age of data. Furthermore, for many subpopulations, there is limited or no data collected over a sufficient period of time to examine trends. Based on a 2009 review of the worldwide status of polar bears, one of 19 subpopu...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
5
Arctic sea ice food web - schematic illustration Arctic sea ice food web - schematic illustration
Sea ice represents a unique ecosystem in the Arctic, providing habitat to specialized iceassociated species that include microorganisms, fish, birds, and marine mammals. Individual species use sea ice in different ways depending on their biological needs. Ice algae form the base of the food web. Some algae stay attached to the bottom of the ice, some fall into the water column, and some fall to the bottom of the sea, and so provide food for speci...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
4
Ice coverage and primary production in the Arctic Ice coverage and primary production in the Arctic
Temperature changes may influence fish populations both directly, through shifts to areas with preferred temperature, and indirectly through the food supply and the occurrence of predators. The length of the ice-free period in the Arctic, for example, affects annual primary production, which is the basis of the food chain supporting populations of fish, sea mammals, and seabirds. As the amount of ice in the Arctic has considerably reduced since t...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
4
Location of datasets in the Arctic Species Trend Index (ASTI) Location of datasets in the Arctic Species Trend Index (ASTI)
Dramatic changes, such as sea ice loss, are projected to occur in Arctic ecosystems over the next century. Understanding how the Arctic’s living resources, including its vertebrate species, are responding to these changes is essential in order to develop effective conservation and adaptation strategies. Arctic species that are adapted to these extreme environments are expected to be displaced, in part, by the encroachment of more southerly specie...
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
Simulated projections for Polar cod distribution with global warming Simulated projections for Polar cod distribution with global warming
Polar cod (Boreogadus saida) was found to be sensitive to the warming scenarios and the model predicted that it would be extirpated in most of its range even under the milder warming scenario. This is due to its occurrence in the Arctic Ocean, which largely precludes it from moving northwards. Polar cod was predicted to be extirpated around Greenland and its abundance was largely reduced in other parts of the Arctic Ocean after 30 years of hypot...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Arctic terrestrial species trends 1970-2005 (ASTI) Arctic terrestrial species trends 1970-2005 (ASTI)
Dramatic changes, such as sea ice loss, are projected to occur in Arctic ecosystems over the next century. Understanding how the Arctic’s living resources, including its vertebrate species, are responding to these changes is essential in order to develop effective conservation and adaptation strategies. Arctic species that are adapted to these extreme environments are expected to be displaced, in part, by the encroachment of more southerly specie...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
3
Arctic genetic trends - lemming in Arctic Russia Arctic genetic trends - lemming in Arctic Russia
Nucleotide diversity estimates based on the complete sequences of mitochondrial genome in the collared lemming indicate how past climate has structured the genetic component of biodiversity. Lower diversity in regions (green) affected by the northward forest expansion during the Holocene warm climatic events compared to Western Beringia, where there was no forest expansion, suggests a reduction of effective size due to regional range contracti...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
4
Simulated projections for Polar cod distribution with global warming Simulated projections for Polar cod distribution with global warming
Polar cod (Boreogadus saida) was found to be sensitive to the warming scenarios and the model predicted that it would be extirpated in most of its range even under the milder warming scenario. This is due to its occurrence in the Arctic Ocean, which largely precludes it from moving northwards. Polar cod was predicted to be extirpated around Greenland and its abundance was largely reduced in other parts of the Arctic Ocean after 30 years of hypot...
01 May 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
3
Distribution and current trend of polar bear subpopulations throughout the circumpolar Arctic Distribution and current trend of polar bear subpopulations throughout the circumpolar Arctic
Polar bears occur in 19 relatively discrete subpopulations with an estimated worldwide abundance of 20,000– 25,000 animals. Our knowledge of the status and trend of each subpopulation varies due to availability, reliability, and age of data. Furthermore, for many subpopulations, there is limited or no data collected over a sufficient period of time to examine trends. Based on a 2009 review of the worldwide status of polar bears, one of 19 subpopu...
01 May 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
3
Towns and industrial activities in the Arctic Towns and industrial activities in the Arctic
The Arctic is home to approximately 4 million people, with the share of indigenous and non-indigenous populations varying widely between the Arctic states. Larger settlements are usually located in resource-strategic positions. Rich deposits of natural resources are spurring industrial activity in the region. The Russian Arctic, for example, holds 1.5 of the country’s population, but accounts for 11% of its gross domestic product and 22% of its e...
13 Oct 2010 - by Riccardo Pravettoni, UNEP/GRID-Arendal
4
Polar bear sub-populations and pollution Polar bear sub-populations and pollution
There are thought to be between 20,000 and 25,000 bears in the world, which occur in19 relatively discrete sub-populations, some of which are shared between nations. Topping the food chain in the Arctic, the polar bear is exposed to high levels of pollutants that are magnified with each step higher in the food web (a process known as biomagnification). Recent studies have suggested that the immune system may be weaker in polar bears with higher l...
13 Oct 2010 - by Riccardo Pravettoni, UNEP/GRID-Arendal
4
Marine mammals in the Arctic Marine mammals in the Arctic
Seven species of marine mammals live in the Arctic year-round – the bowhead whale, beluga whale, narwhal, ringed seal, beaded seal, walrus, and polar bear - and many more migrate to the Arctic seasonally. Many marine mammals aggregate in specific areas across the Arctic, for example to feed, or for whelping, pupping or moulting. A common feature of marine mammals in the Arctic is that they are associated with sea ice, although the ecological rela...
13 Oct 2010 - by Riccardo Pravettoni, UNEP/GRID-Arendal
5
Projected changes in the Arctic climate, 2090 Projected changes in the Arctic climate, 2090
The averages of the scenarios in the Arctic Climate Impact Assessment (ACIA) are presented in this figure, for the year 2090, with the surface temperatures over land, the size of the polar ice cap, and the outer limits of permafrost.
13 Oct 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
4
Vegetation and land cover in the Arctic Vegetation and land cover in the Arctic
The land mass in the Arctic - Greenland and parts of Canada, Alaska, Russia and the Nordic countries - surrounds the Arctic Ocean. In the low Arctic, down to the temperate regions, the taiga coniferous forests represents a vast band of deep forests. North of the taiga, the tundra of the Arctic - with low vegetation, shrubs and various degrees of permafrosts spreads out. Beyond the tundra, there might be barren regions with only rock and few plant...
13 Oct 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
4
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
4
Retreat of the snowcapped volcano of Santa Isabel, Colombia Retreat of the snowcapped volcano of Santa Isabel, Colombia
Between 1959 and 1996, the snowcapped volcano of Santa Isabel in Colombia showed a 44% decrease in its ice-covered peak. This process of decrease in ice has continued, causing it to lose its attraction as a tourist site, with significant economic consequences.
22 Nov 2010 - by Riccardo Pravettoni, UNEP/GRID-Arendal
3
Sea level rise caused by the melting of mountain and subpolar glaciers Sea level rise caused by the melting of mountain and subpolar glaciers
Another process that results in rising sea levels is the addition of water mass from land ice. Melting glaciers and ice caps, as well as the vast ice sheets of Greenland and Antarctica, raise sea-levels if their water mass enters the ocean as melted water or icebergs (Pritchard et al. 2009, Steig et al. 2009, Velicogna 2009). Furthermore, it is estimated that melting of tropical glaciers (most of them are considered small) could cause an increas...
22 Nov 2010 - by Viktor Novikov, UNEP/GRID-Arendal
4
Changes to Coconut Beach (Dominica) after the 1995 hurricane season Changes to Coconut Beach (Dominica) after the 1995 hurricane season
During a period between May 1994 to September 1995 the profile of the beach dramatically changed. A rising sea level combined with more storms, washed away vulnerable beaches. With the sand gone, the coast is more vulnerable to waves going further inland, threatening fresh water wells with salinisation, leading to land erosion, and making the areas less attractive for tourism. When a beach starts to deteriorate, the process can be amazingly quick...
17 May 2005 - by Viktor Novikov, UNEP/GRID-Arendal
3
Previous | 1 2 3 4 5 6 7 8 9 10 11 | Next