Arctic sea ice ties for smallest area this winter

The 2011 Arctic sea ice extent maximum that marks the beginning of the melt season appears to be tied with that for 2006 for the least amount of ice ever measured by satellites, say scientists at the University of Colorado Boulder's National Snow and Ice Data Center.

Sea ice on the Arctic Ocean usually starts growing in September and hits its maximum area in February or March. The CU-Boulder research team believes the lowest annual maximum ice extent of 5,650,000 square miles (14.64 million square km) occurred on March 7. The maximum ice extent was 463,000 square miles below the 1979-2000 average, an area slightly larger than the states of Texas and California combined. The 2011 measurements were tied with those from 2006 as the lowest maximum sea ice extents measured since satellite record keeping began in 1979.

That area of ice-covered water is 471,000 square miles (1.2 million square km) below the average maximum ice extent observed by satellites from 1979 to 2000, the center said in a statement.

The seven lowest maximum Arctic sea ice extents measured by satellites all have occurred in the last seven years, said CU-Boulder Research Scientist Walt Meier (left) of the National Snow and Ice Data Center, who participated in the latest study. "I'm not surprised by the new data because we've seen a downward trend in winter sea ice extent for some time now."

As of Tuesday, March 22, the extent of the ice had shrunk for five straight days, but there is a chance it could expand again, the center said.

"Sea ice extent in February and March tends to be quite variable, because ice near the edge is thin and often quite dispersed," the statement read.

This thin ice is sensitive to weather, which can make it move or melt quickly, and it often stays around the maximum for days or weeks, as it has done this year.

Arctic sea ice extent -- the area the ice covers in summer and winter -- is one measure scientists use to track changes in global climate. Virtually all climate scientists believe shrinking Arctic sea ice is tied to warming temperatures in the region caused by an increase in human-produced greenhouse gases being pumped into Earth's atmosphere. Because of the spiraling downward trend of Arctic sea ice extent in the last decade, some CU scientists are predicting the Arctic Ocean may be ice free in the summers within the next several decades.

Scientists believe Arctic sea ice functions like an air conditioner for the global climate system by naturally cooling air and water masses, playing a key role in ocean circulation and reflecting solar radiation back into space, said Meier. In the Arctic summer months, sunlight is absorbed by the growing amounts of open water, raising surface temperatures and causing more ice to melt.

"I think one of the reasons the Arctic sea ice maximum extent is declining is that the autumn ice growth is delayed by warmer temperatures and the ice extent is not able to 'catch up' through the winter," said Meier. "In addition, the clock runs out on the annual ice growth season as temperatures start to rise along with the sun during the spring months."

Since satellite record keeping began in 1979, the maximum Arctic sea ice extent has occurred as early as Feb. 18 and as late as March 31, with an average date of March 6. (At left: 2011 Greenland ice) Since the CU-Boulder researchers determine the maximum sea ice extent using a five-day running average, there is small chance the data could change.

In early April (approximately the second week of April) CU-Boulder's National Snow and Ice Data Center will issue a formal announcement on the 2011 maximum sea ice extent with a full analysis of the winter ice growth season, including graphics comparing 2011 to the long-term record.

Source:
Reuters,"Arctic sea ice ties for smallest area this winter", accessed March 24, 2011
RedOrbit, "Arctic Sea Ice Loss Continuing", accessed March 25, 2011

Researchers warn Arctic fishing under-reported

The amount of fish caught in the Arctic has been dramatically under-reported for decades, making the northern ocean environment appear far more pristine than it really is, according to a new study. (At left: salmon)

An estimated 950,000 tons of fish were caught in Russian, Canadian and U.S. Arctic waters between 1950 and 2006, which is 75 times higher than reported by the United Nation's agency that records catch levels, according to Canadian researchers.

Ineffective reporting "has given us a false sense of comfort that the Arctic is still a pristine frontier when it comes to fisheries," lead researcher Dirk Zeller of the University of British Columbia said in a written statement.

The results of the study were published this week in the journal Polar Biology.

The researchers said they collected data on fish catches from a variety of sources in the region, including those kept by indigenous people, and compared it to what was reported to the U.N.'s Food and Agriculture Organization.

The researchers estimate that, between 1950 and 2006, 89,000 tons of fish were caught in Alaskan coastal waters in the Arctic and 94,000 tons in Canadian waters, but neither Canada nor the United States supplied that data to the U.N.

An estimated 770,000 tons of fish were caught in Russian waters off Siberia, far above the 12,700 tons reported by the United Nations, according to the study.

The researchers said that most Arctic conservation efforts concentrate on protecting animal such as seals and polar bears, and they warned that the marine mammals will not survive if the rest of the region's ecosystem is neglected.

The researchers said the problems could become worse if climate change pushes more fish into polar waters and melting sea ice allows greater access by the world's fishing fleets.

Researchers at the university issued a study in December warning that global fleets were running out of fishing grounds, and the waters of the Arctic and Antarctic were among the few areas remaining for exploitation.


Source:
Reuters, "Researchers warn Arctic fishing under-reported", accessed February 5, 2011

Polar bear swims for 9 days in search of sea ice

One of Alaska's own polar bear experts is making headlines this week with a new revelation about the toll climate change is taking on polar bears as a result of melting sea ice. In one of the most dramatic signs ever documented of how shrinking Arctic sea ice impacts polar bears, researchers at the U.S. Geological Survey in Alaska have tracked a female bear that swam nine days across the deep, frigid Beaufort Sea before reaching an ice floe 426 miles offshore.

The marathon swim came at a cost: With little food likely available once she arrived, the bear lost 22% of her body weight and her year-old female cub, who set off on the journey but did not survive, the researchers said.

"Our activity data suggests that she swam constantly for nine days, without any rest. Which is pretty incredible," said George M. Durner, a USGS zoologist and a lead author of the study, published last month in the journal Polar Biology.

"We have observed other long-distance swimming events. I don't believe any of them have been as long in time and distance as what we observed with her," he said. "How often does this happen? We're trying to get a handle on that."

Polar bears spend much of their waking lives on the shifting Arctic sea ice floes. They survive mainly on the ringed seals that are also dependent on sea ice and swim in abundance in the relatively shallow coastal waters of the continental shelf.

Polar bears spend much of their waking lives on the shifting Arctic sea ice floes. They survive mainly on the ringed seals that are also dependent on sea ice and swim in abundance in the relatively shallow coastal waters of the continental shelf.

But sea ice has been melting dramatically in recent years, forcing polar bears during the fall open-water periods to either forage from shore or swim longer distances in search of sea ice.

Bears that retreat to land usually find little or no food there, and "typically … spend the duration fasting while they await the re-formation of ice needed to access and hunt seals," according to a 2008 government study.

"We are in awe that an animal that spends most of its time on the surface of sea ice could swim constantly for so long in water so cold," George M. Durner told BBC News of the "marathon" bear, which reported the findings Tuesday. Durner is a research zoologist with the U.S. Geological Survey in Anchorage at the Alaska Science Center.

With data collected over a two-month period in 2008 using data from a GPS-equipped radio collar, along with body temperature monitoring equipment and motion sensors previously attached to the bear., Durner and his colleagues chronicled the bear's eastward journey along the Alaska coast, during which she made that incredible nine-day, 426-mile swim from land to floating pack ice over the sea's deep waters. Along the way, she lost her yearling cub and 22 percent of her body weight: more than 100 pounds.

"Our observation confirms that yes, indeed, polar bears are capable of, they have the ability to undergo these extraordinary behaviors such as long distance swimming. No one else has been able to provide data like this before," Durner said in an interview from his Anchorage office Tuesday, January 25, 2011.

The comprehensive data comes from a unique mix of hi-tech gadgets that were affixed to the bear in August 2008, each equipped with computer chips that recorded and preserved the data that scientists were able to download two months later, when the bear was again captured.

Through satellite tracking, motion detectors and thermometers they kept tabs on her every hour of every day. They not only knew where she was but also whether she was walking or swimming, resting or active, and how warm or cold it was outside or in the water and, with a sensor buried in the fat beneath her skin, they recorded her own body temperature -- a blend of gadgets designed to assist not only the ongoing studies, but also a USGS University of Wyoming study looking specifically at the physiology of polar bear on land and sea ice during summer in the Beaufort Sea. For scientists, having all of the technology on a single animal was a rare expedition that, as best as it could, let them travel alongside the mother bear via data diary.

"What makes her particularly unique is the wealth of data that we have available from this animal to be able to tell a story about what she experienced," Durner said.

What was her life like in the two months scientists eavesdropped on her? She started as a healthy, 500-pound bear that was lactating and caring for a yearling cub. At some point she left Alaska's coast and went for a swim in search of sea ice, the floating surface bears use to travel over hunting grounds.

Along the way, during the swimming journey that went on far longer than scientists have to-date recorded, she lost her cub. Durner suspects it died from exhaustion during the long, 426-mile swim from land to pack ice, but there's no way to know for sure. The floating ice pack was farther off shore than usual -- a trend attributed to melting sea ice and climate change. And it was over deep waters which aren't as food-rich as the shallower continental shelf, over which summer pack ice in years past has been found.

By the time scientists caught up with the polar bear again in October 2008, she had traveled hundreds of miles eastward toward Canada. Her cub was gone, she had stopped lactating and she had lost a lot a weight.

In the past, polar bears haven't had to swim as far to reach the ice, Durner said, adding that the mother bear probably had no idea what she was getting herself into.

"The bear probably went swimming back in 2008 and probably didn't say to itself, 'I've got 687 kilometers to swim.' It probably just said, 'I'll go swimming and pretty soon I'll come to the sea ice habitat where I want to be," he said.

The bear's journey shows that while, yes, polar bears can adapt to changing environments, it comes at great cost, Durner said. Cubs may not be able to survive the hardships and females may not be able to maintain enough body weight to give birth or successfully care for their young.

Norway's 'Spy on the ice'

High Tech Cams get High Tech videos of Polar Bears

Durner and his colleagues aren't the only people employing technology to help satisfy their curiosity about what polar bears are up to at any given moment. On the other side of the Arctic Ocean, the British Broadcasting Corp. recently had its own surveillance operation underway. In Svalbard, an island cluster in Norway's northernmost region, the "Spy on the Ice" crews deployed specially designed video cameras to surreptitiously gather hard-to get images.

Polar Bears Play Football with Spy Cams

While "Blizzard cam," "snowball cam," "drift cam" (left) and "iceberg cam" look like they belong in "Star Wars V: The Empire Strikes Back," they are actually a collection of covert, cold-weather camera housings created to operate unmanned and withstand the arctic climate. Some, equipped with skis, can quietly travel up to 40 mph and remain operational for up to a week. Motion and heat sensors allow the cameras to lay in wait until the bears show up, coming to life just in time to record the action.

Polar Bear Flirtation

In one clip, a snowball cam (left) chronicled a cub's first emergence out of the birthing den. And although a blizzard left a blanket of snow clouding the lens, a paw swipe from the curious mother cleared the view, which the camera also caught. The program's narrator sums up the remarkable results: "The cub's first steps outside the den, filmed by his mother."

Cub Emerges for first time from winter den

In another clip, iceberg cam records images above and below the water and manages to capture a polar bear's stealthy hunt for a seal. Iceberg Cam (left) was designed to blend seamlessly amongst the ice flows. It’s powerful thrusters produced enough speed to keep up with swimming bears. Iceberg Cam was decked out with two cameras for above and below water filming. It's an impressive display of clever planning and predator prowess, and in one shot the bear is caught eerily popping up behind the seal undetected, just before slinking back into the water to make its move.

Knowing that polar bears are curious and may even be prone to vandalism, the camera's designers equipped blizzard cam (the gadget which slides, self-propelled on skis, along the ice and snow shown at right) with a getaway plan. In the event of an attack, it's able to deploy snowball cam as a decoy -- a distraction meant to keep the bears occupied long enough for the larger module to flee to safety.

Turns out, it works. But the bears did get the better of the cams. One consolation? Snowball cam filmed to the very end of its paw-smashing, teeth-tugging demise.

Polar Bears Smash SpyCams on Ice

The result is a stunning collection of footage chronicling the life of the polar bear, from which the BBC recently aired a 60-minute program, "Polar Bear: Spy on the Ice."

Source:
Alaska Dispatch, "Polar bear swims for 9 days in search of sea ice", by Jill Burke, accessed January 28, 2011
Los Angeles Times, "Polar bear's long swim illustrates ice melt", accessed January 31, 2011

Global warming may be harming Pacific walrus: scientists

The Pacific walrus may be the new icon of global warming. Like polar bears, walruses are dependent on floating sea ice to rest, forage for food and nurture their young. Like polar bears, walruses are suffering because of a scarcity of summer and fall sea ice in Arctic waters that scientists attribute to climate change.

And like polar bears, which were listed as threatened in 2008, protections under the Endangered Species Act may be granted to walruses, even though it is hard to get an accurate count of their population.

"You don't have to know how many passengers are on the Titanic to know it's in trouble when it hits an iceberg," said Rebecca Noblin, staff attorney for The Center for Biological Diversity, which sued to obtain Endangered Species Act safeguards for the walrus.

For the lumbering, long-tusked marine mammals, problems caused by scarce ice are showing up on beaches in northwestern Alaska and across the Bering Strait in northeastern Siberia.

For the third time in four years, thousands of walruses have hauled out on the Alaska shore, congregating this summer on the shorelines of the Chukchi Sea instead of spreading over chunks of floating ice.

That ice has largely disappeared. This year, summer sea ice levels reached their third-lowest point since satellite measurements started in 1979, according to the National Snow and Ice Data Center in Boulder, Colorado.

As the sea ice retreats away from the shore, there is less and less ice available to the walruses -- mostly females and their young -- over relatively shallow waters where they can feed. Ultimately, if they no longer can find ice over shallow waters, they must swim ashore -- sometimes over great distances. Those that survive the trip "haul out" along the shoreline where conditions tend to much less favorable than they would be on ice over shallow waters.

As many as 15,000 walruses began crowding the shore near Point Lay, Alaska, in August and are just starting to disperse as ice forms in chilly fall weather, federal biologists said. (At right: walruses in 2009 from a similar haul-out).

According to Alaska Dispatch:

"USGS scientists traveled to Point Lay earlier this month to tag some of the walruses in an effort to track and study their movement. They're particularly interested in how much more swimming the hauled out walruses, most of which are females, will have to do to find food and how that extra effort will affect the animals' health. They're also worried about how young walruses -- which rely on a mother's care for two years and which nurse for the first six to seven months of life -- will fare."

CROWDED BEACHES

Such congregations place walruses far from the best sources of clams and other food they pluck from the icy waters and, if they are young and small, at risk of sudden and grisly death especially if there is a stampede.

Under similar conditions in September 2009, large numbers of walruses hauled out along the Alaskan and Russian shores. On 14 September 2009, scientists encountered 131 walrus carcasses near Icy Cape, Alaska. (see left) A USGS report (Enumeration of Pacific Walrus Carcasses on Beaches of the Chukchi Sea in Alaska Following a Mortality Event, September 2009) said:

"All appeared to be young animals .... The events that led to the death of these animals are unknown, but appear to be related to the loss of sea ice over the Chukchi Sea continental shelf. In years prior to this event, other investigators have linked walrus deaths at other Chukchi Sea coastal haulouts to trampling, exhaustion from prolonged exposure to open sea conditions, and separation of calves from their mothers."

The U.S. Fish and Wildlife Service was to announce last month its recommendation for an Endangered Species Act listing. The deadline was extended to January 31 to give the agency time to evaluate two new studies. (Walrus distribution map at left)

Both reports warn of a grim future. One predicts that the Chukchi Sea will be ice-free for three months a year by mid-century and up to five months by the end of the century, and that ice-free periods in the Bering Sea also will expand.

The other study calculates that the ice-dependent walruses have a 40 percent chance of being extinct or in danger of extinction by century's end.

A LONGER 'COMMUTE?'

The latest estimate of the total Pacific walrus population is 129,000, said Joel Garlich-Miller, a Fish and Wildlife Service biologist. That figure is based on incomplete aerial surveys conducted by U.S. and Russian scientists and is probably on the low end, he said. (Map at right: Walrus range)

Another key question is whether walruses stuck on shore are spending significantly more energy searching for food than they would if they could forage from floating ice.

"There's this commute that's new to them, and it costs them," said Anthony Fischbach, a biologist and walrus specialist with the U.S. Geological Survey.

He also suspects there may be fewer calves than there should be.

"It's certainly shocking to see over 100 dead calves that were apparently healthy. But it's hard to put it in context," said Fischbach, one of the biologists who documented the carnage.

"Are these the strong ones that come ashore, whereas the ones that are weaker couldn't make the 150-mile swim to shore?"

To try to find answers, he and his colleagues have embarked on studies to count the adult-calf ratio within herds and use radio tracking to pin down their travels for food.

Advocates of Chukchi Sea oil drilling and other development are expected to oppose any Pacific walrus listing. The state of Alaska, which supports oil drilling in walrus habitat, already has sued to overturn the listing of polar bears and formally opposed new protections considered by the government for ice-dependent Arctic seals. The state also objected to habitat protections proposed for polar bear and endangered Steller sea lions.

Source:
Reuters, "Global warming may be harming Pacific walrus: scientists", accessed October 5, 2010