New Delhi (NVI): Scientists have predicted for the first time when, where and how polar bears are likely to disappear, warning that if greenhouse gas emissions stay on their current trajectory, all but a few polar bear populations in the Arctic will probably be gone by 2100.
According to a study by the University of Toronto in Canada, published in Nature Climate Change, by as early as 2040, it is very likely that many polar bears will begin to experience reproductive failure cause starvation due to melting of ice, leading to local extinctions.
The study says “aggressive” cuts to greenhouse gas emissions are needed now to save the animals from extinction.
The bears rely on the ice, which forms above the open waters, to reach their prey. A loss of the ice caused by global warming will force the animals on to land, where they must rely on fat reserves due to a lack of food.
The study examines how the bears will be affected under two different greenhouse gas emissions scenarios. The researchers found that under a business-as-usual emissions scenario, polar bears will likely probably only remain in the Queen Elizabeth Islands – the northernmost cluster in Canada’s Arctic archipelago – at the end of the century. And even if greenhouse gases are moderately mitigated, it is still likely that the majority of polar bear populations in the Arctic will experience reproductive failure by 2080.
Extinctions that would take about 10,000 years in normal evolutionary time frames are now occurring every century. Scientists said that this was the direct result of human intervention in the environment, in the form of degradation, pollution and climate change.
Scientists estimate that there are fewer than 26,000 polar bears left, spread out across 19 different subpopulations that range from the icescapes of Svalbard, Norway, to Hudson Bay in Canada to the Chukchi Sea between Alaska and Siberia.
Polar bears draw on energy reserves built up during the winter hunting season to make it through lean summer months on land or time spent on ice in unproductive waters. Though the bears are used to fasting for months, their body condition, reproductive capacity and survival will eventually diminish if they are forced to go too long without food.
The authors said their study was limited by the use of a single “earth systems model”, which is used to determine how sea ice will be affected, and because of uncertainties and variations in bear behaviour and energy usage among different sub-populations.
-CHK
