US sets aside 'critical habitat' for polar bear in Alaska

The Obama administration is setting aside 187,000 square miles (484,330 sq. kilometers) in Alaska as a "critical habitat" for polar bears, an action that could add restrictions to future offshore drilling for oil and gas.

The total, which includes large areas of sea ice off the Alaska coast, is about 13,000 square miles (33,670 sq. kilometers), or 8.3 million acres (3.36 million hectares), less than in a preliminary plan released last year.

Tom Strickland, assistant secretary for fish, wildlife and parks at the Interior Department, said the designation would help polar bears stave off extinction, recognizing that the greatest threat is the melting of Arctic sea ice caused by climate change.

"This critical habitat designation enables us to work with federal partners to ensure their actions within its boundaries do not harm polar bear populations," Strickland said. "We will continue to work toward comprehensive strategies for the long-term survival of this iconic species."

Designation of critical habitat does not in itself block economic activity or other development, but requires federal officials to consider whether a proposed action would adversely affect the polar bear's habitat and interfere with its recovery.

Nearly 95 percent of the designated habitat is sea ice in the Beaufort and Chukchi seas off Alaska's northern coast. Polar bears spend most of their lives on frozen ocean where they hunt seals, breed and travel.

Alaska Gov. Sean Parnell and the state's oil and gas industry had complained that the preliminary plan released last year was too large and dramatically underestimated the potential economic impact. The designation could result in hundreds of millions of dollars in lost economic activity and tax revenue, they said.

The U.S. Fish and Wildlife Service said reductions included in the final rule were mostly due to corrections that more accurately reflect the U.S. border in the Arctic Ocean. Five U.S. Air Force radar sites were exempted from the final rule, as were Native Alaskan communities in Barrow and Kaktovik, Alaska.

The Interior Department has declared polar bears "threatened," or likely to become endangered, citing a dramatic loss of sea ice. Officials face a Dec. 23 deadline to explain why the bears were listed as threatened instead of the more protective "endangered."

Kassie Siegel, a lawyer for the Center for Biological Diversity, an environmental group that has filed a lawsuit to increase protections for the polar bear, hailed the designation of critical habitat.

"Now we need the Obama administration to actually make it mean something so we can write the bear's recovery plan – not its obituary," she said.

Siegel called for the administration to impose a moratorium on oil and gas drilling in bear habitat areas. "An oil spill there would be a catastrophe," she said. "That seems like an understatement."

The Arctic Slope Regional Corp., which advocates for Alaska Native business interests, said in a statement that the decision disproportionately impacts Alaska Natives and called the designation the "wrong tool" for conserving the polar bear because it does nothing to address climate change.

"The burden of the impacts will be felt by the people of the Arctic Slope," said Tara Sweeney, vice president of external affairs for ASRC, which is based in Barrow, Alaska. "This is a quality of life issue for our people."

Kara Moriarty, deputy director of the Alaska Oil and Gas Association, said the action would hurt oil and gas exploration in Alaska by creating more delays and added costs to projects in what already is a high-cost environment, she said.

"The companies and the industry will be required to go through more permitting and create mitigation measures without a direct benefit to the polar bear or oil and gas development," Moriarty said. "The Fish and Wildlife Service has found over and over again our activities pose no threat to the polar bear."

Source:
The Guardian, "US sets aside 'critical habitat' for polar bear in Alaska", accessed December 6, 2010

Climate change threatens slow swimming narwhals

Narwhals are the 'marathon runners' of the oceans, scientists have discovered.

The Arctic-living tusked whales are exceptional endurance athletes, possessing a greater density of slow-twitch fibers in their muscles than any other marine mammal studied.

This ability also means that narwhales are one of the sea's slowest swimmers. That places them at high risk from climate change, as narwhals will not be able to cope with shifting, highly mobile ice floes caused by warmer seas. The highly mobile ice makes icebergs that are too big for these animals to swim beneath, and changes the reliability of known breathing holes.

Details of the narwhal's extreme endurance ability and susceptibility to climate change are published in the journal Marine Mammal Science.

Narwhals are one of three species of cetacean living in the Arctic, alongside the beluga whale and bow-head whale.

They are also known as the 'unicorns of the sea' due to their long, elongated tusks.

However, narwhals now have a new claim to fame, as the 'marathon runners' of the oceans, say researchers Professor Terrie Williams and Dr Shawn Noren of the University of California, Santa Cruz and Dr Mike Glenn, of Sea World, San Diego, US.

They made the first study of the physiological capacity of narwhals and found that the cetaceans have the highest levels of myoglobin in their muscles of any marine mammal measured to date. High levels of myoglobin allow large amounts of oxygen to be stored.

Narwhals also have the highest percentage of slow twitch muscle fibers within swimming muscles for any marine mammal, the researchers discovered. In narwhals, around 87% of their swimming muscle fibers are of the slow twitch variety, which respond slowly but do not tire easily.

Narwhals actually have a muscle composition close to that of human endurance runners, as the leg muscles of an elite marathon runner contain more than 90% slow twitch muscle fibers.

"This specialized morphology makes them excellent divers," Prof Williams stated, as their muscles can store and efficiently use large amounts of oxygen.

"But it comes at a cost. They appear to be one of the slowest swimmers out there."

Climate threat

This highly specialized swimming behavior puts narwhals at significant risk from the effects of climate change, warn the researchers.

Listed as 'near-threatened to vulnerable' on the IUCN list of endangered animals, around 75,000 narwhals are thought to survive, inhabiting the ice-choked waters of the Canadian Arctic and Greenland.

This means narwhals have to be able to predict where holes in the ice are, in order to reach the surface to breathe.

In fact, Prof William's study reveals that narwhals swim so slowly that they can only cover a distance of around 1.4km in any direction before they run out of oxygen, despite their endurance capability. So to survive, they need to be able to find a break in the ice at least every 1.4km.

"The big surprise is how little of the Arctic waters narwhals can use due to the limitation of breathing," says Prof Williams.

Worse, climate change will reduce the amount of suitable ocean, further endangering the species.

"Warmer temperatures are creating more icebergs and larger floes," says Prof Williams. "The problem is not the ice is disappearing, rather in the course of disappearing the ice has become highly mobile. That makes icebergs that are too big for these animals to swim beneath, and changes the reliability of known breathing holes."

The researchers estimate that just 10% of the water under larger ice floes contains enough breathing holes, or fish to hunt, to be suitable for narwhals. Shifting winds can also quickly move ice around, making the appearance of breathing holes even more unpredictable.

"A wrong decision [taken by a narwhal] or a shifting wind moving ice could be fatal."

Source:
BBC, "Climate change threatens slow swimming narwhals", accessed September 9, 2010

Estimated icecap loss halved

Estimates of the rate of ice loss from Greenland and West Antarctica, one of the most worrying questions in the global warming debate, should be halved, according to Dutch and US scientists.

In the last two years, several teams have estimated Greenland is shedding roughly 230 gigatons of ice, or 230 billion tons, per year and West Antarctica around 132 gigatons annually.

But, according to the new study, published in the Sept issue of the journal Nature Geoscience,(subscription required) the ice estimates fail to correct for a phenomenon known as glacial isostatic adjustment. This has led to a serious over-estimation of the rate of ice melt in the Arctic and Greenland.

Measuring a disappearing ice cap is actually quite difficult to do, as the areas in question are remote, hostile environments and the exact depth of ice is often unknown. This has caused a lot of argument among climate scientists regarding how much ice is melting and running into the sea, as this affects predictions of sea-level rise and other aspects of climate modeling. (Floating sea ice, like that which makes up most of the Arctic cap apart from Greenland, is less of an issue as its melting doesn't affect the sea level.)

Glacial Isostatic adjustment is the term for the rebounding of Earth's crust following the last Ice Age. Glaciers that were kilometers thick smothered Antarctica and most of the northern hemisphere for tens of thousands of years, compressing the elastic crust beneath it with their titanic weight.

'A good analogy is that it's like a mattress after someone has been sleeping on it all night,' said researcher Bert Vermeersen of Delft Technical University, in the Netherlands. The weight of the sleeper creates a hollow as the material compress downwards and outwards. When the person gets up, the mattress starts to recover.

Satellite data from NASA's Gravity Recovery and Climate Experiment (GRACE) has been used for preliminary ice rate estimates. GRACE consists of two spacecraft flying in tandem to measure Earth's gravitational field very precisely. These measurements enable a better understanding of ocean surface currents and ocean heat transport. The mission is able to measure changes in sea-floor pressure and show how the mass of the oceans change. It will also measures and monitors ice sheets and changes in the storage of water and snow on the continents.

The estimates from GRACE were until now uncorrected for the phenomenon of "rebound", where the Earth's crust rises as ice is removed. No one, however, was sure how much impact the "rebound" effect would have on the estimate. It turns out that it has quite a bit of impact.

Now a team of researchers based at NASA's Jet Propulsion Laboratory and in the Netherlands say they have the answer.

"The corrections for deformations of the Earth’s crust have a considerable effect on the amount of ice that is estimated to be melting each year," explains Dr Bert Vermeersen. "We have concluded that the Greenland and West Antarctica ice caps are melting at approximately half the speed originally predicted."

Vermeersen and his colleagues' calculations show that as little as 500 gigatons of ice or even less could have melted from Greenland during 2003-2009, translating into less than 2mm of sea-level rise. In the case of Greenland, it could be that the current estimates are triple what they should be.

Source:
The Straits Times, "Estimated icecap loss halved", accessed September 8, 2010
The Register, "Greenland ice loss rates 'one-third' of what was thought", accessed September 8, 2010