polar bears and global warming

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Eng102
19 April 2014
Polar Bears and Global Warming
Polar bear populations along with global warming tend to be very controversial subjects. Both are subject to scrutiny as to whether polar bear populations are in decline and if global warming is the cause. However depending on who you talk to, you will hear that the polar bear population is stable and some instances increasing. Both sides have plenty of evidence to back up their claim. No matter which side of the fence you are, the fact remains that polar ice cap is disappearing, and it is having a profound effect on the Polar Bears. Polar bears are one of eight species of bears in the world (OurAmazingPlanetStaff). They are said to have evolved from the brown bear species some five million years ago (Polar bears international). In that time they have adapted very well to life in the arctic habitat. To date scientists believe that they have identified 19 populations living in four different ice regions of the world. The polar bear calls the U.S. (Alaska), Canada, Russia, Greenland and Norway home (OurAmazingPlanetStaff). Each of these regions contain sustainable populations of the ringed seal, which is the main diet of the polar bear (Polar bears international). Evidence documents how the loss of their primary habitat negatively affects the polar bears long term survival. In order to maintain healthy population the polar bears depend on sea ice to hunt seals to accumulate enough energy to survive the long periods when seal are unavailable. The loss of the sea ice dramatically reduces the time to access the seals, resulting in longer periods of fasting and lower body conditions. This has also resulted in an increase in cannibalism (Derocher). Another severe impact of the loss, is the decrease in accessibility to denning areas, causing more stress and ultimately leading to fewer and smaller cubs (Derocher) The end result is a lower class of cubs as well bears of other age classes finally causing the species to become extinct (Stirling and Derocher).The loss of the sea ice is one of the main reasons the U.S. has placed the polar bears on the endangered species list (Interior). Global warming is the collection of carbon dioxide and other air pollutants trapped in the atmosphere creating an ever thickening blanket. This blanket traps the sun’s heat and is causing the planet to ultimately warm up. This trapped heat has already caused unrepairable damage to our world. One of the most severe cases is in the arctic where the perennial polar ice cap is declining at the rate of 9 percent per decade (National Resources Defense Council). Nine percent may not sound like a lot, but melting glaciers are causing early snowmelt and severe droughts throughout the world. Global warming is responsible for the disruption in ecosystems, more importantly the loss of the sea ice that polar bears need to survive. Since living on the sea ice is the polar bears habitat, the loss is causing them to have to swim longer distances. In addition, it also means the loss of their prime hunting time/areas. In perspective, loss of hunting equals loss of nutrients, and energy needed to survive. Loss of the sea ice due to global warming cause’s polar bears who are already stressed and energy deficient to swim longer distances. The longer distances are seeing more polar bears drown due to loss of energy or inability to maintain energy to complete these longer distances (Monnett and Gleason). Even when adult polar bears have enough energy to survive the long distance swims, it is another sad fact that most cubs cannot store enough energy to make the long swims. The cubs end up succumbing to the elements and perishing (Sheer).

With 19 populations around the world four of them are said to be in decline, while six are said to be stable or actually increasing. The other nine have not been studied enough to know one way or another (Polar bears international). Critics will tell...
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