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Tuesday, February 2, 2010

Polar bears facing extinction due to climate change

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Some animals around the globe have been facing threats due to man caused reasons. Polar beers, coral reefs, sharks and tuna fish are some of these animals facing threats to such an extent that these are having been forced to the verge of extinction. A number of organizations around the globe have been persistently fighting to ensure survival of endangered and threatened species of animals. The Center for Biological Diversity and Greenpeace are two of such organizations.
Polar bears, taxonomically known as Ursus maritimus is supposed to be the native of the Arctic circle that encompasses the Arctic ocean, its surrounding seas and surrounding land masses. It is regarded as the world’s largest carnivore. The weight of an adult male polar bear ranges around 360 to 678 kg and that of an adult female is about the half of the male’s. Polar bear is considered to have been evolved in a narrow ecological niche, with body features that have been adopted due to cold habitat. The polar bears though mostly borne on land, have to spend most of their lives at sea in the frozen surroundings.

In its range, a polar bear stands as an apex predator. There is a close relationship between the population of ringed seals and polar bears. The abundance of ringed seals sometimes appears to regulate the population density of polar bears. An evolutionary pressure on seals due to polar bears has been reported by researchers which determine the density of polar bears. On the other hand the density of polar bears is reported to regulate the density and reproduction of ringed seals. In Antarctic the ringed seals enjoy more breathing space as no major predator is found there and hence they need not to develop much camouflage and mostly remain black in colour. On the other hand arctic ringed seals have to take major adaptations like white furs. The babies of most of the arctic ringed seals are white where as those of Antarctic ringed seals are dark in colour. Though polar bears don’t enter into any conflict with other predators of their habitat, the encroachment by brown bear often leads to antagonistic encounters.



Ringed Seal, Image 1



Ringed Seal Image 2

The ecological status of polar bears is reported to be insecure. A polar bear is classified as vulnerable species. Reports reveal that out of 19 sub populations, 8 show a declining trend. Unrestricted hunting of polar bears from over a decade, though it has been regarded as a key figure in the material, spiritual and cultural life of the indigenous people of Arctic has raised the international concern. Hunting of polar bears has been a part of the culture of these people.
Now the global warming is being included by IUCN as the most significant threat to the existence of polar bears. According to a report of IUCN if a present trend of global warming continues polar bears are sure to disappear within coming 100 years. Since global warming tends to melt all the ice, polar bears are bound to face an acute scarcity of food shortage in near future that may act as a strongest force to cause extinction of polar bears. It was on May 14, 2009 that United States Department of Interior listed the polar bear as a threatened species under its Endangered Species Act. Russia lists the polar bear as a species of concern.

 According to the Center for Biodiversity polar bears have been listed among one of the threatened species due to climate change. The organization in a report mentions that - While domestic law prevents U.S. imports and exports of polar bear items, Canada, Greenland, and Norway allow significant international trade in such goods. This trade must be strictly monitored and regulated in order to halt high harvest levels of this vulnerable species.


Polar bears are a potentially endangered species living in the circumpolar north. They are animals which know no boundaries. They pad across the ice from Russia to Alaska, from Canada to Greenland and onto Norway's Svalbard archipelago.


Biologists estimate that there are 20,000 to 25,000 bears with about sixty percent of those living in Canada. The main threat to polar bears today is the loss of their icy habitat due to climate change. Polar bears depend on the sea ice for hunting, breeding, and in some cases to den. The summer ice loss in the Arctic is now equal to an area the size of Alaska, Texas, and the state of Washington combined.

At the most recent meeting of the IUCN Polar Bear Specialist Group (Copenhagen, 2009), scientists reported that of the 19 subpopulations of polar bears, eight are declining, three are stable, one is increasing, and seven have insufficient data on which to base a decision—this is a change from five that were declining in 2005, five that were stable, and two that were increasing.


During the meeting, delegates renewed their conclusion from previous meetings that the greatest conservation challenge to the polar bear is ecological change in the Arctic related to climate warming. In areas where long-term studies are available, populations are showing signs of stress due to shrinking sea ice. Canada's Western Hudson Bay population has dropped 22% since the early 1980s. The declines have been directly linked to an earlier ice break-up on Hudson Bay.


A long-term study of the Southern Beaufort Sea population, which spans the northern coast of Alaska and western Canada, has revealed a decline in cub survival rates and in the weight and skull size of adult males. Such declines were observed in Western Hudson Bay bears prior to the population drop there. Another population listed as declining is Baffin Bay.

According to the most recent report from the Polar Bear Specialist Group, this population, shared by Greenland and Canada, may simultaneously be suffering from significant sea ice loss and substantial over-harvesting, putting the population at great risk of a serious decline. Similarly, the Chukchi Sea population, which is shared by Russia and the United States, is likely declining due to illegal harvest in Russia and one of the highest rates of sea ice loss in the Arctic.


Some Native communities in Canada have been reporting increasing numbers of polar bears on land. Traditional hunters believe this indicates an increased population, although the increased presence on land may, in fact, be related to shrinking sea ice and changes in the bears' distribution patterns. Data is needed to understand the change. The U.S. Fish and Wildlife Service states, "In the declining polar bear population of Canada's Western Hudson Bay, extensive scientific studies have indicated that the increased observation of bears on land is a result of changing distribution patterns and a result of changes in the accessibility of sea ice habitat."


In the 1960s and 1970s, hunting was the major threat to the bears. At the time, polar bears were under such severe survival pressure from hunters that a landmark international accord was reached, despite the tensions and suspicions of the Cold War. The International Agreement on the Conservation of Polar Bears was signed in Oslo, November 15, 1973 by the five nations with polar bear populations: Canada, Denmark (Greenland, Norway, the U.S., and the former U.S.S.R.The polar bear nations agreed to prohibit random, unregulated sport hunting of polar bears and to outlaw hunting the bears from aircraft and icebreakers as had been common practice. The agreement also obliged each nation to protect polar bear denning areas and migration patterns and to conduct research relating to the conservation and management of polar bears. Finally, the nations agreed to share their polar bear research findings with each other. 


Member scientists of the Polar Bear Specialist Group now meet every three to four years under the auspices of the IUCN World Conservation Union to coordinate their research on polar bears throughout the Arctic. The Oslo agreement was one of the first and most successful international conservation measures enacted in the 20th century. Its legacy continues today, with member scientists from each nation continuing to work together in face new threats to the bears including climate change, pollution, industrial activities, and poaching.





Key Words : Extinction, IUCN,Ringed seals,Polar bears, Climate Change

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