Far North Science

Woolly Mammoth
Credit: Wikipedia Commons

Once upon a time, the prehistoric steppes of North America hosted a menagerie of giant mammals — woolly mammoths, saber-toothed tigers, cave bears, camels, horses, lions, giant ground sloths as well as bison, moose, musk-oxen and even spear-chucking humans dressed in fur.

As any video-watching child knows well, the late centuries of the ice age fairly rocked with these immense beasts and their furry companions.

And then, about 13,000 years ago, most of this fabulous megafauna rapidly died out. Mammoths went extinct. Lions and tigers and horses and sloths disappeared. Scientists have long debated the causes.

Was it overhunting by Pleistocene humans with spears, wild fire and shrewd killing strategies? Or was it a sudden shift in the climate that destroyed the productive grassy steppe that supported this network of grazers and their predators?

Now, an international team of scientists led by Richard Firestone of Lawrence Berkeley National Laboratory has uncovered evidence that an immense explosion — accompanied by a nuclear-strength shockwave — triggered a catastrophic climate shift that wiped out life across America. The work follows up on earlier findings by Firestone that a supernova 41,000 years ago may have created a killer space rock and sent it tumbling into the home planet.

In other words, just like the dinosaurs before them, the mammoths may have been fried by an asteroid.

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Microwave data from the Special Sensor Microwave
Imaging radiometer was used to create this image of
the 2007 Greenland melting anomaly which reflects the
difference between the number of melting days occur-
ring in 2007 and the average number of melting days
during the period 1988 – 2006.
Credit: NASA/Earth Observatory

As if the Arctic Ocean record meltdown wasn’t bad enough, NASA scientists say the Greenland ice pack has been melting faster.

Remember: Loss of the Greenland ice sheet is one of the final, city-swallowing catastrophes of runaway climate warming. Put that ice in the ocean as water, and sea level rises almost 24 feet.

This summer, melt ranged over the entire ice sheet. But with a twist:

“Melting in high-altitude areas was greater than ever at 150 percent more than average,” NASA reported in this online story. “In fact, the amount of snow that has melted this year over Greenland could cover the surface size of the U.S. more than twice.”

The results came from Marco Tedesco, a research scientist at the Joint Center for Earth Systems Technology, cooperatively managed by NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland at Baltimore County.

With satellite data, Tedesco comparged average snow melt between 1988 and 2006 with the melt observed during 2007. What he found matches may as alarming as the sudden shinkage of the polar ice cap north of Alaska and Siberia.

“In high altitude areas over 1.2 miles above sea level, the melting index — an indicator of where melting is occurring and for how long — was significantly higher than average,” NASA reported in this online story.

“Melting over those areas occurred 25-30 days longer this year than the observed average in the previous 19 years.”

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Source: NASA

The recent shrink of the Arctic ice cap has stunned scientists and swamped previous projections. After melting back at a rate never seen before, the 2007 minimum ice extent fell 1 million square miles below the 29-year average for September — the loss of a habitat as large as Argentina.

The decline occurred much faster than scientists thought possible, consuming as much ice in one season as one might expect to lose over three consecutive summers, according to a story published online by NASA.

Here’s the latest from the Arctic slush bowl. And the news is not reassuring.

As of Sept. 25, the ice cover in the Arctic Ocean hovered at about 1.61 million square miles — a scant 1 percent increase over the all-time minimum extent observed about 10 days earlier. The Northwest Passage, more ice free than at any time in decades, had slowly begun to clog up. But open water extended hundred of miles north and west of Alaska, exposing coastal villages to enormous fetches for storms and forcing marine mammals to deal with the smallest and most seaward ice habitat of their lives.

Stranded on the Beaufort Sea shore?
Source: FWS/Susanne Miller

As the Bush Administration spends time chatting with other major carbon-producing nations about making soft, ineffectual (and almost certainly symbolic) reductions in greenhouse gas emissions, the Arctic has gone soggy, appearing as ice-free as some climate researchers once predicted for 2050. (See the UN meeting on clmate change earlier in week.)

In fact, given the accelerated rate of melt, several scientists now say the ocean could become ice free in summer as early as 2030. That’s only 23 years — less than a generation for coastal residents, ice seals and bears.

“The amount of ice loss this year absolutely stunned us,” ice scientist Mark Serreze of the National Snow and Ice Data Center, told the Boulder Daily Camera in this story. “It didn’t just beat all previous records — it completely shattered them.”

“Going, going, gone,” Deborah Williams of Alaska Conservation Solutions, told the House Select Committee on Energy Independence and Global Warming, in a story published in the Anchorage Daily News. “We must take action now; it is urgent. We want to be part of the solution, not just the poster child of the problem.”

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Remains of bearded seal (Erignathus barbatus) of all ages
have been recovered from the Amaknak Bridge site on
the Island of Unalaska in the eastern Aleutians. Shown
here are mandibles from a fully mature prehistoric
adult and a pup several weeks old (top). Bearded seals
give birth on sea ice in early April and nurse their young
for about three weeks.

Winter ice once clogged the Bering Strait until late summer and surrounded the rugged shores of the Pribilof Islands most of the year, according to a new study of ancient animal bones at an Aleutian archeaological site.

This frigid climate, occurring during a mysterious 2,000-year-long cold snap that ended about 2,500 years ago, was powerful enough to trigger decisive shifts in the migrations of whales and the breeding habits of Northern fur seals, ultimately creating a thriving ecology very different than the one observed during the past few hundred yeaers.

Two Canadian archaeozoologists — Susan Crockford and Gay Frederick of Pacific Identifications Inc — say the findings suggest a startling conclusion: that marine mammals like seals may be far more adaptable that people realize.

“Sea ice not only extended further south than it does today but persisted longer into the summer,” they added. “No other type of evidence has documented an expansion of sea ice in the Bering Sea during this time period, which appears to explain the prehistoric distribution of at least one North Pacific marine mammal.”

Among other things, the two scientists found remains of a newborn bearded seal pup, an ice seal, suggesting that floes existed near Unalaska Island as late as April.

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Methane seekers: Radio reporter Melissa Block, UAF scientist
Katey Walter, and NPR producer Art Silverman
Photo: River Gates of Anchorage

It bubbled. It boiled. It stank.

University of Alaska Fairbanks scientist Katey Walter just wanted to show a National Public Radio news crew a smidgin of methane seeping from a lake on Alaska’s North Slope near Barrow. It’s all part of her investigations into the supergreenhouse gas, and how it oozes into the atmosphere all over the Far North.

Bacteria that digest dead vegetation and other edible gunk on the lake bottom produce methane that gets trapped in the muck, sometimes for eons. When lake-bottom permafrost melts in late summer, this flammable gas bubbles up into the air.

A potentially huge problem in the event of widespread meltdown of the Far North’s “permanently frozen” earth, this methane venting occurs on a small scale wherever vegetation rots.

But Walter and the journalists came upon a churning, bubbling spot in the middle of the lake located on the vast brown tundra near Barrow.

“When they reached their destination,” wrote UAF writer Sandra Boatwright in an online story, “Walter and the crew found even more than they bargained for — A lake violently boiling with escaping methane.”

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Syun-Ichi Akasofu

Many scientists have got the relationship between rising greenhouse gases and warming temperatures flat wrong, says Alaska’s Syun-Ichi Akasofu in an Wall Street Journal essay.

And is there legitimate consensus that human-generated emissions are the cause of the current bout of climate change?

Definitely not, Akasofu says.

“Definitive scientific proof that the present warming is mostly caused by the greenhouse effect … is simply an assumption that has morphed into a fact,” Akasofu wrote in an essay that appeared a few weeks ago. (It was based on an article from Far Eastern Economic Review, “Storm in a Teacup Over Climate Change.”)

As a reply, the climate change blog published by Nature took on Akasofu’s assertions one by one in Some climate change fallacies.

Akasofu, a pioneer in aurora research, seems to be “confused,” the blog argued.

“Akasofu immediately starts out on the wrong foot by claiming there are two sides, those of believers and non-believers,” wrote climate scientist Kevin Trenberth. “But it is not a matter of belief, it is a matter of scientific facts!”

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Sea ice north of Alaska during summer 2007.
Photo by Jenny Hutchings

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Ned Rozell is a science writer at the institute.

The news from the top of the world, according to William Chapman, who follows the fate of sea ice from his office at University of Illinois at Urbana-Champaign:

“September 12, 2007 . . . The (northern hemisphere) sea ice area is currently at its historic minimum (2.92 million square kilometers) representing a 27 percent drop in sea ice coverage compared to the previous (2005) record (northern hemisphere) ice minimum.”

The ice that floats on the Arctic Ocean is now the smallest conglomeration of frozen jigsaw puzzle pieces that people have seen in the era of satellites. That record is short, only going back to 1979, but the ice loss has been outracing some conservative computer models. According to an Alaska scientist just back from the ice pack, northern ice is not what she had seen before.

Jenny Hutchings is a sea-ice researcher for the International Arctic Research Center at the University of Alaska Fairbanks. She cruised the Beaufort Sea north of Alaska for more than a month from late July to late August. She was a passenger on the Canada Coast Guard icebreaker Louis St. Laurent. It was her second straight year in the area.

Satellite measurements aren’t perfect, and Hutchings noticed that some areas the satellites revealed as ice-free were instead ice, with water ponded on top. But for the most part, she noticed an ice mass in bad shape.

“We were seeing unusually thin, rotten ice, all the way to 79 degrees north,” Hutchings said. “That’s where you would expect some of the heaviest ice, and we were having no trouble at all getting through.”

Hutchings was on the cruise to validate satellite observations with what she saw and to continue tracking ice around the Beaufort Sea, the portion of the Arctic Ocean north of Alaska and northwest of Canada. She said much of the ice they encountered was ice that has survived from one to three winters.

She was surprised in the northern regions of the trip to find no first-year ice that formed last winter. New ice can grow to five feet thick in one winter, but it is also more vulnerable to melting than multi-year ice.

Source: NSIDC

The Louis St. Laurent encountered relatively easy going throughout the entire cruise, Hutchings said, including their route along the northwestern edge of Canada’s Banks Island.

“There wasn’t much ice around Banks Island,” she said. “Normally, there’s a lot of old, multi-year ice there and it’s more concentrated.”

USGS scientists, including Steve Amstrup of Anchorage, recently released a report about how shrinking sea ice could doom a majority of the world’s polar bears, and all of them off the coast of Alaska, within 50 years. On the northern portions of her cruise, Hutchings saw several polar bears, which seemed to be in good health, she said.

Other than the loss of white bears, which is very sad indeed, why should we care about the loss of ice that very few people will ever see?

Scientists have described the far north as “the refrigerator of the northern hemisphere,” and a small or vanished ice pack could result in less snow in places as far away as Colorado, and strange weather throughout the northern hemisphere.

Hutchings said she would look at her data this winter in an attempt to find out if the Beaufort Sea ice can recover during the cold season, which just began in the far north.

“The more I look at the situation this year, the more I realize how unusual it is,” she said.

Source: NSIDC

It’s got opportunity. There are fingerprints on the weapon. But what is the motive?

In a finding consistent with rising concentrations of greenhouse gases in the atmosphere, warm water oozing north from the Atlantic Ocean has once again been fingered as a prime suspect in the generation-long murder of Arctic ice.

In this instance, a remarkable study from Rutgers Institute of Marine and Coastal Studies found rising sea-surface temperatures in the Barents Sea as the factor liquidating winter ice cover northeast of Scandinavia.

And then the feedback mechanism kicks in. Less ice in winter leads to less ice in summer, with amplified warming of the sea, which in turn leads to even less ice in following winters. The meltback snowballs, in a manner of speaking.

“In the Barents Sea, I expected more influence from atmospheric heating; but it [the retreat of the ice edge] seems to be governed almost entirely by warming from the ocean,” said Jennifer Francis, associate research professor, in a story posted by the Institute.

Not so with the Bering Sea near Alaska.

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