Climate change and warming shrinking Arctic sea ice and polar bears, experts say

Majestic, more and more hungry and liable to disappearing, the polar bear relies on one thing melting away on our warming planet: sea ice.

Within the harsh and unforgiving Arctic, the place frigid chilly is not only a lifestyle however a necessity, the polar bear stands out. However the place it lives, the place it hunts, the place it eats — it’s disappearing underfoot within the essential summertime.

“They’ve simply all the time been a revered species by individuals, going again a whole bunch and a whole bunch of years,” mentioned longtime authorities polar bear researcher Steve Amstrup, now chief scientist for Polar Bear Worldwide. “There’s simply one thing particular about polar bears.”

Scientists and advocates level to polar bears, marked as “threatened” on the endangered species record, because the white-hot warning sign for the remainder of the planet — “the canary within the cryosphere.” As world leaders meet in Glasgow, Scotland, to attempt to ramp up efforts to curb local weather change, the specter of polar bears looms over them.

United Nations Surroundings Program head Inger Andersen used to steer the Worldwide Union for the Conservation of Nature, which screens and classifies species in bother. She asks: “Do we actually wish to be the technology that noticed the top of the power of one thing as majestic because the polar bear to outlive?”

Arctic sea ice — frozen ocean water — shrinks through the summer time because it will get hotter, then types once more within the lengthy winter. How a lot it shrinks is the place international warming kicks in, scientists say. The extra the ocean ice shrinks in the summertime, the thinner the ice is general, as a result of the ice is weaker first-year ice.

Julienne Stroeve, a College of Manitoba researcher, says summers with out sea ice are inevitable. Many different consultants agree together with her.

Former NASA chief scientist Waleed Abdalati, now a prime College of Colorado environmental researcher, is considered one of them.

“That’s one thing human civilization has by no means identified,” Abdalati mentioned. “That’s like taking a sledgehammer to the local weather system and doing one thing enormous about it.”

The warming already within the oceans and within the air is dedicated — like a freight prepare in movement. So, it doesn’t matter what, the Earth will quickly see a summer time with lower than 1 million sq. kilometers of sea ice scattered in tiny bits throughout the Arctic.

The large query is when the Arctic will “seem like a blue ocean,” mentioned Mark Serreze, director of the Nationwide Snow and Ice Information Heart.

4:19
New e book particulars the plight of polar bears

Perhaps as early because the 2030s, most probably within the 2040s and virtually assuredly by the 2050s, consultants say.

The Arctic has been warming twice as quick as the remainder of the world. In some seasons, it has warmed 3 times quicker than the remainder of the globe, mentioned College of Alaska at Fairbanks scientist John Walsh.

That’s due to one thing referred to as “Arctic amplification.” Basically, white ice within the Arctic displays warmth. When it melts, the darkish sea absorbs rather more warmth, which warms the oceans much more rapidly, scientists say.

There are 19 completely different subpopulations of polar bears within the Arctic. Every is a bit completely different. Some are actually in bother, particularly the southernmost ones, whereas others are fairly near secure. However their survival from place to position is linked closely to sea ice.

“As you go to the Arctic and see what’s taking place with your personal eyes … it’s miserable,” mentioned College of Washington marine biologist Kristin Laidre, who has studied polar bears in Baffin Bay.

Shrinking sea ice means shrinking polar bears, actually.

Within the summertime, polar bears exit on the ice to hunt and eat, feasting and placing on weight to maintain them by the winter. They like areas which might be greater than half coated with ice as a result of it’s the best searching and feeding grounds, Amstrup mentioned. The extra ice, the extra they will transfer round and the extra they will eat.

Simply 30 or 40 years in the past, the bears feasted on a buffet of seals and walrus on the ice.

Within the Nineteen Eighties, “the males have been enormous, females have been reproducing frequently and cubs have been surviving effectively,” Amstrup mentioned. “The inhabitants seemed good.”

With ice loss, the bears haven’t been doing as effectively, Amstrup mentioned. One signal: A better proportion of cubs are dying earlier than their first birthdays.

Polar bears are land mammals which have tailored to the ocean. The animals they eat — seals and walruses largely — are aquatic.

The bears fare finest once they can hunt in shallow water, which is usually near land.

“When sea ice is current over these near-shore waters, polar bears could make hay,” Amstrup mentioned.

0:34
Manitoba to formally acknowledge polar bear as provincial emblem

However in recent times the ocean ice has retreated far offshore in most summers. That has pressured the bears to float on the ice into deep waters — typically almost a mile deep — which might be devoid of their prey, Amstrup mentioned.

Off Alaska, the Beaufort Sea and Chukchi Sea polar bears present a telling distinction.

Go 30 to 40 miles offshore from Prudhoe Bay within the Beaufort Sea “and also you’re in very unproductive waters,” Amstrup mentioned.

Additional south within the Chukchi, it’s shallower, which permits bottom-feeding walruses to thrive. That gives meals for polar bears, he mentioned.

“The bears within the Chukchi appear to be faring fairly effectively due to that further productiveness,” Amstrup mentioned. However the bears of the Beaufort “give us an actual good early warning of the place that is all coming to.”

Whilst world leaders meet in Scotland to attempt to ratchet up the trouble to curb local weather change, the scientists who monitor sea ice and watch the polar bears know a lot warming is already set in movement.

There’s an opportunity, if negotiators succeed and all the things seems excellent, that the world will as soon as once more see an Arctic with vital sea ice in the summertime late this century and within the twenty second century, consultants mentioned. However till then “that door has been closed,” mentioned Twila Moon, a Nationwide Snow and Ice Information Heart scientist.

So hope is melting too.

“It’s close to not possible for us to see a spot the place we don’t attain an basically sea ice-free Arctic, even when we’re capable of do the work to create a lot, a lot decrease emissions” of heat-trapping gases, Moon mentioned. “Sea ice is a kind of issues that we’ll see attain some fairly devastating lows alongside that path. And we are able to already see these influences for polar bears.”