An Ice-Free Arctic … Happening Before Our Eyes

Summer at the North Pole may be gorgeous, but the news from there is devastating again this year.

"The land of the polar bear" -- where in fact there is no land, only frozen sea surface -- is melting.

America's "summer air conditioner" -- the vast fields of sea ice that constantly rotate around the North Pole and feed cooling winds that sweep down to the lower 48 -- is continuing to shrink back this summer.

It is the effect of global warming occurring far faster than scientists predicted just a few years ago.

The refreezing of sea ice during the long, dark polar night of winter is also reportedly declining sharply.

Scientists believe this is all due not only to higher average temperatures of the air but also to the water, contributing to an Arctic that could be ice-free in summer far sooner than predicted only a year ago.

"It's continuing the pattern of extreme sea-ice loss," Mark Serreze of the National Snow and Ice Data Center said to ABC News. "What we're seeing in 2006 is way below the average ice extent over the 20 years ending in 2000."

There are still three weeks to go before the Arctic's "summer sea ice minimum," and already experts at the data center can see the bad news -- and you can, too, at "Figure 2" when you click here.

That light-blue line snaking down and hugging the dotted line? It's bad news.

It shows the 2006 summer melt back of sea ice virtually as great as that in the summer of 2005 -- which all means major changes under way for life, natural and human -- in the Arctic, the United States and worldwide.

The public is getting smarter and smarter about the importance of sea-ice loss, Serreze says.

The arcane craft he and his colleagues practice in the academic quiet of their labs and computer rooms is no longer quite so lonely.

All sorts of people now call up wanting to know what's up with Arctic melt back.

"That's why we created this new blow-by-blow site," Serreze said. "People can watch along with us" as each warming Arctic month shatters ever more sea ice -- and often records as well.

Bad News Bears

It's also more bad news for the world's polar bears, as confirmed in a new article in the peer-reviewed scientific journal Arctic.

Claire Parkinson, a NASA ice expert and author, told ABC News about new satellite data that show "the date at which the sea ice breaks up each summer, forcing polar bears back onto land, has been coming seven [days] or eight days earlier each decade" in Canadian Arctic regions she studies.

Polar bears -- Latin name Ursus maritimus or "Sea Bear" -- get virtually all their food, principally seals, on the sea ice.

The scientists say global warming means that summer melt backs are now dumping polar bears on land three weeks earlier each summer than in the mid-'70s, which means more hungry bears on land and more trouble for humans.

The Holy Grail -- 'What We Really Need to Know'

"But sea-ice volume is what we really need to know," Serreze said.

"It's the Holy Grail" for sea-ice experts, he says, adding that the news here is probably worse than any we've heard about sea-ice extent.

News from NASA that Arctic summer sea ice melted back 30 percent in the last 30 years -- and could well be gone completely by about the year 2070 -- made headlines in the summer of 2005.

But those findings measured only the loss of surface area, not the thickness -- thus the volume -- of the ice.

Satellites are close to being able to measure ice thickness accurately, Serreze said.

New techniques are closing in on how to measure the amount of ice "freeboard" floating above the surface, which with a little fancy math can tell scientists the volume of the ice.

The world's first nuclear submarine, the USS Nautilus, made the first submarine sonar measurements of Arctic sea-ice thickness in 1958.

"In the early '60s, they found thicknesses in the North Pole region of about 3½ meters [about 11 feet], and then in the late '80s and early '90s it was down to about 2½ meters [7 feet or 8 feet,]" Serreze said to ABC News.

"They needed that info back then for two reasons. First, to know where they could surface in an emergency. Second, to know where they could surface if there was a 'boomer' and they needed to fire off some missiles."

A third reason now adds great value to those ice-thickness measurements from Cold War submarines -- the accelerating advance of global warming.

Both U.S. and former Soviet Union ice-thickness measurements have been declassified and are available to the world's ice experts.

Serreze says that a number of his colleagues are now working on Arctic summer sea-ice thickness, and that their findings so far show massive volume loss over the last 30 years.

Serreze cites work by Wieslaw Maslowski of the U.S. Navy Post Graduate School in Monterey, Calif., that strongly suggests it's not only Earth's warming atmosphere that is melting the Arctic ice from above.

"Wieslaw is saying it's also the warming sea currents melting the sea ice from below. He's been arguing that 2070 is way too far out in the future -- way too conservative. I suspect he may be right," Serreze said.

Both these reporters walking out on the Arctic sea ice last summer in the company of scientists and Coast Guard officers of the Ice Breaker USCG Healy, were, as Arctic first timers, naturally worried about walking on thin ice a mile and a half above the sea floor.

"How thick? Is it safe?" we asked several times, stepping from small landing craft onto the beautiful white and blue undulating planes of ice reaching to the horizon.

We always got answers something like: "It's still OK -- it's about four feet thick. It used to be eight feet thick, but now it's about four in most places."

Coasties and scientists are watching that thickness ever more closely now as they step off their landing boats, racing to gather what knowledge they can of this largely unknown and breathtakingly beautiful environment that is now melting away fast.

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