As changes in climatic temperatures melt sea ice, the US Geological Survey predicted that two-thirds of the polar bear population will die out by the year 2050. A dramatic decline in polar bears is already occurring in our lifetime, which, according to historical data, is but a very small fraction of the time these animals have roamed the vast seas of the Arctic.
The main threat to the polar bears is the loss of their sea-ice habitat that is caused by global warming. As suggested by these animals’ specific scientific name, Ursus maritimus, they are actually a species of marine mammals that spend a great deal of time at sea than they do on land. It is on the Arctic ice that the polar bears make their living, which is why rising temperatures of the Earth’s atmosphere is such a serious threat to their well-being.
What Are the Effects of Global Warming on Polar Bears?
1. Decline in the Species’ Population Size.
In the southern portions of these animals’ habitat’s range, such as Hudson Bay, Canada, there is no sea ice during the summer, and they must live on land until the bay freezes in the fall, where they can hunt on the ice again. While on land during the hot months, these bears eat little or even nothing.
In just 2 decades, the ice-free period on the Hudson Bay has increased by an average of 20 days, cutting short the polar bears’ seal hunting season by nearly a third of a month. The ice is freezing later in the fall, but it is the earlier spring ice melt that is especially difficult for these mammals, when they have a narrower time-frame during which they hunt on a critical season when seal pups are born. As a result, the average weight among the bears has decreased by 15%, causing their reproduction rates to decline. The animals’ population on the Hudson Bay is now down more than 20%.
Research predicted that the declining sea ice could see two-thirds of the world’s polar bear population becoming extinct in the middle of the 21st century. Another study, which used 10 global climate models, even projected a decrease in the polar bear numbers in the Beaufort Sea of 50% to 99% by the end of the century.
Now, to keep their numbers relatively healthy (though these are still low), scientists strongly suggest that global temperatures should not exceed 1.25 degrees Celsius above the 1980-1999 average.
2. Retreating Sea Ice Platforms.
Retreating sea ice platforms imply many threats other than the obvious habitat loss. Remaining ice is moving farther from the shore, which makes it less accessible to polar bears. Aside from this, the larger gap of open water between the land and ice is also contributing to rougher wave conditions, which makes it more hazardous for these mammals to swim from the shore to sea ice.
In fact, biologists discovered 4 drowned polar bears in the Beaufort Sea in 2004, and suspected the actual number of bears that have drowned might have been considerably higher. It was never before observed that these scientists attributed the drowning incidents to a combination of rougher seas and retreating ice.
3. Less Time for Polar Bears to Hunt.
The effects of the reduction in sea-ice thickness and extent, shorter periods of maximum ice extent and the changes in sea-ice structure and dynamics probably varies in different regions of the Arctic, but all of these are potentially harmful to the condition and reproductive success of these mammals and their prey.
With regards to the polar bears in the southern range, for example in James Bay and Hudson Bay of Canada, sea ice is now melting earlier in the spring and forming later in the autumn, and the time bears have on the ice is their best season, when they hunt seals and fish easily, and they restore their body fat and fitness. However, this critical time for storing up their energy for the hot season (when there is less ice and little available food) is becoming dangerously limited. As the periods without supply of food have become longer, the overall body condition of polar bears have decreased.
This is particularly serious for pregnant bears or those that are nursing their young, as well as for the cubs themselves. In Hudson Bay, scientists have discovered the primary cause of death among bear cubs to be either the lack of fat on nursing mothers or lack of food.
4. Polar Bear Food Becoming Scarce.
This is directly related to the previously mentioned effect of global warming on polar bears. Exacerbating the problems caused by the loss of these animals’ hunting areas, it is expected that the shrinking polar ice cap will also cause the number of seals, polar bears’ prey, to decline. The decrease in ice platforms near productive areas for fish that seals eat is affecting their reproduction rates and nutritional status. These mammals are going hungry for longer periods of time, which results in them developing cannibalistic behavior. Though it is already known that they would kill for dominance or kill cubs to breed with the females, outright predation for food was not observed by biologists in the past.
5. Polar Bears Being Classified as a Threatened Species.
The polar bears were listed as an endangered species in 2008 under the Endangered Species Act mainly because of the drop of their primary habitat—sea ice. Though this is the case, they are restricted the law’s protections, so their future is still very much in jeopardy.
What Can We Do To Solve The Problem?
Considering that humans have caused this problem, it is arrogated that humans can also fix it. Research shows that time has remained to conserve polar bears if people would act soon significantly reduce greenhouse gas emissions. This means that all communities around the world should work together now in playing individual roles to ensure these animals a better future.
Will Our Actions Make a Difference?
Although taking immediate action to stop climate change does not yield immediate results, new studies suggest that we could see favorable effects in about 10 years. So, our actions today can do well in preventing potentially catastrophic changes from taking place, not only for polar bears but also for all of us in this world.