Steve Connor, The Independent 27 Jun 08;
It seems unthinkable, but for the first time in human history, ice is on course to disappear entirely from the North Pole this year.
The disappearance of the Arctic sea ice, making it possible to reach the Pole sailing in a boat through open water, would be one of the most dramatic – and worrying – examples of the impact of global warming on the planet. Scientists say the ice at 90 degrees north may well have melted away by the summer.
"From the viewpoint of science, the North Pole is just another point on the globe, but symbolically it is hugely important. There is supposed to be ice at the North Pole, not open water," said Mark Serreze of the US National Snow and Ice Data Centre in Colorado.
If it happens, it raises the prospect of the Arctic nations being able to exploit the valuable oil and mineral deposits below these a bed which have until now been impossible to extract because of the thick sea ice above.
Seasoned polar scientists believe the chances of a totally icefreeNorth Pole this summer are greater than 50:50 because the normally thick ice formed over many years at the Pole has been blown away and replaced by hugeswathes of thinner ice formed over a single year.
This one-year ice is highly vulnerable to melting during thesummer months and satellite data coming in over recent weeksshows that the rate of melting is faster than last year, when therewas an all-time record loss of summer sea ice at the Arctic.
"The issue is that, for the first time that I am aware of, the NorthPole is covered with extensive first-year ice – ice that formed last autumn and winter. I'd say it's even-odds whether the North Pole melts out," said Dr Serreze.Each summer the sea ice melts before reforming again during the long Arctic winter but the loss of sea ice last year was so extensive that much of the Arctic Ocean became open water, with the water-ice boundary coming just 700 miles away from the North Pole.
This meant that about 70 per cent of the sea ice present this spring was single-year ice formed over last winter. Scientists predict that at least 70 per cent of this single-year ice – and perhaps all of it – will melt completely this summer, Dr Serreze said.
"Indeed, for the Arctic as a whole, the melt season startedwith even more thin ice than in 2007, hence concerns that we may even beat last year's sea-ice minimum. We'll see what happens, a great deal depends on the weather patterns in July and August," he said.
Ron Lindsay, a polar scientist at the University of Washington in Seattle, agreed that much now depends onwhat happens to the Arctic weather in terms of wind patterns and hours of sunshine. "There's a good chance that it will all melt awayat the North Pole, it's certainly feasible, but it's not guaranteed," Dr Lindsay said.
Thepolar regions are experiencing the most dramatic increasein average temperatures due to global warming and scientists fear that as more sea iceis lost, the darker, open ocean will absorb more heat and raise local temperatures even further. Professor Peter Wadhams of Cambridge University, who was one of the first civilian scientists to sail underneath the Arctic sea ice in a Royal Navy submarine,said that the conditions are ripe for an unprecedented melting of the ice at the North Pole.
"Last year we saw huge areas of the ocean open up, which hasnever been experienced before. People are expecting this to continuethis year and it is likely to extend over the North Pole. It isquite likely that the North Pole will be exposed this summer – it's not happened before," ProfessorWadhamssaid.
There are other indications that the Arctic sea ice is showingsigns of breaking up. Scientists at the Nasa Goddard Space Flight Centre said that the North Water 'polynya' – an expanse of open water surrounded on all sides by ice – that normally forms near Alaska and Banks Island off the Canadian coast, is muchlarger than normal. Polynyas absorb heat from the sun and eat away at the edge of the sea ice.
Inuit natives living near Baffin Bay between Canada and Greenland are also reporting thatthe sea ice there is starting to break up much earlier than normal and that they have seen wide cracks appearing in the ice where it normally remains stable. Satellite measurements collected over nearly 30 years show a significant decline in the extent of the Arctic sea ice, which has become more rapid in recent years.
This summer may see first ice-free North Pole
Seth Borenstein, Associated Press Yahoo News 28 Jun 08;
There's a 50-50 chance that the North Pole will be ice-free this summer, which would be a first in recorded history, a leading ice scientist says.
The weather and ocean conditions in the next couple of weeks will determine how much of the sea ice will melt, and early signs are not good, said Mark Serreze. He's a senior researcher at the National Snow and Ice Data Center and the University of Colorado in Boulder, Colo.
The chances for a total meltdown at the pole are higher than ever because the layer of ice coating the sea is thinner than ever, he said.
"A large area at the North Pole and surrounding the North Pole is first-year ice," Serreze said. "That's the stuff that tends to melt out in the summer because it's thin."
Preliminary February and March data from a NASA satellite shows that the circle of ice surrounding the North Pole is "considerably thinner" than scientists have seen during the five years the satellite has been taking pictures, NASA ice scientist Jay Zwally said Friday. He thinks there is slightly less than a 50-50 chance the North Pole will be ice-free.
Last year was a record year for ice melt all over the Arctic and the ice band surrounding the North Pole is even thinner now.
There is nothing scientifically significant about the North Pole, Serreze said. But there is a cultural and symbolic importance. It's home to Santa Claus, after all. Last August, the Northwest Passage was open to navigation for the first time in memory.
A more conservative ice scientist, Cecilia Bitz at the University of Washington, put the odds of a North Pole without ice closer to 1 in 4. Even that is far worse than climate models had predicted, which was 1 in 70 sometime in the next decade, she said.
But both she and Serreze agree it's just a matter of time.
"I would guess within the next 10 year it would happen at least once," Bitz said.
Already, figures from the National Snow and Ice Data Center show sea ice in the Arctic as a whole at about the same level now as it was at its low point last year in late June and early July.
The explanation is a warming climate and a weather phenomenon, scientists said.
For the last couple of decades, there has been a steady melt of Arctic sea ice — which covers only the ocean and which thins during summer and refreezes in winter. In recent years, it has gradually become thinner because more of it has been melting as the Earth's temperature rises.
Then, this past winter, there was a natural weather shift called the Arctic Oscillation, sort of a cold weather cousin to El Nino. That oscillation caused a change in winds and ocean that accelerated a normal flushing of sea ice in the Arctic. That pushed the older thicker sea ice that had been over the North Pole south toward Greenland and eventually out of the Arctic, Serreze said. That left just a thin one-year layer of ice that previously covered part of Siberia.
The National Snow and Ice Data Center: http://nsidc.org/index.html
Thin Ice: The Arctic Meltdown Explained
Andrea Thompson, LiveScience.com Yahoo News 28 Jun 08;
If the North Pole becomes ice-free this summer - the odds for that are 50-50, one scientist says - that doesn't mean that the whole Arctic region will become an open ocean.
Mark Serreze of the U.S. National Snow and Ice Data Center in Colorado told The Independent, a London-based newspaper, "I'd say it's even-odds whether the North Pole melts out."
The article, posted on the newspaper's Web site Friday, generated some confusion as to what would actually happen at the North Pole, and in the Arctic Ocean as a whole, as the summer melt season gears up in the next few weeks.
In a telephone interview with LiveScience, Serreze explained that a melt-out at the North Pole wouldn't mean that all Arctic ice would melt. Rather, the thin, newly-formed ice around 90 degrees latitude could melt away for a few days. Such an event would be significant, he said, because any holes that have appeared in the ice at the North Pole up until now have been a result of winds pushing the sea ice around and creating cracks, not the melt-related processes that have taken hold in the Arctic in recent years.
Usually, the North Pole is covered with thick, perennial ice that forms over several years. But during last summer's record melt, which opened up the fabled Northwest Passage, a substantial amount of older ice melted. (Typically only the thinner, first-year ice melts in the summer, while the thick, perennial ice survives.) Average sea ice extent at the end of the summer was 1.65 million square miles (4.28 million square kilometers), almost 30 percent lower than the previous record low.
As winter cooled the Arctic waters, ice re-formed over the ocean, as it usually does. But this newly formed ice is thinner, first-year ice, more susceptible to melting once summer comes around again.
As it happened, wind patterns and ocean currents over the last few months moved that newly formed ice smack over the North Pole, setting up the situation where at least a temporarily ice-free North Pole could form.
"It's this symbolic thing, I think," Serreze told LiveScience. "This is where Santa Claus lives ... it kind of hits you in the stomach."
The North Pole isn't the only part of the Arctic Ocean covered with this newly-formed ice - a substantial part of the region is capped by this thin frozen veneer. That "we're going to lose a bunch of ice," is more or less certain, Serraze said, but just where that melt will occur is "a roll of the dice."
One factor affecting where and how much ice will melt this summer is the somewhat higher ice extent that re-froze this winter. (While the winter extent was higher this year than last year, it was still about 390,000 square miles (1 million kilometers) smaller than average - that's equal to an area about the size of Texas and New Mexico combined.
Sea ice forms not by spreading out along the surface of the ocean, but rather as water just below the ice freezes onto the underside of the ice. This means that more ice probably also means slightly thicker ice, said Josefino Comiso of NASA's Goddard Space Flight Center, which helps monitor sea ice coverage. Thicker ice is more likely to survive the summer and become second-year ice, becoming thicker still in the winter.
The North Pole is also cooler than lower Arctic latitudes, meaning North Pole ice could better resist melting. Even if it does, there's still the possibility that winds could move the ice around so that a hole that formed at a lower latitude could be pushed over the North Pole, making it ice-free, Serreze said.
It's these weather patterns that scientists will be watching in the coming weeks to get a better sense of what will happen in the Arctic this summer. Serreze says that a warm spring season has put melting about on par with where it was at this point last year.
But other scientists say this summer's melt is unlikely to be as spectacular as last year's.
"We may not see a record minimum at all," said Tharston Markus, also of Goddard.
Scientists are monitoring the sea ice extent daily and say that after the main melt occurs over the next few weeks, they'll have a better idea of what the minimum extent, which typically occurs in mid-September, might be. For now though, all they can do is watch and wait.