Gone missing
John Mcconnico, the Associated Press
Have the icebergs lost their way? In the past, the International Ice Patrol has spotted as many as 2,000 a year migrating south of the Arctic Circle. This year there were none.
By Michael Park
Special to The Hamilton Spectator
(Jun 3, 2006)
A mere 300 metres above the frigid waters of the North Atlantic the debate began. The pilot of the U.S. Coast Guard plane believed the object on the plane's radars was an iceberg. One of two young but experienced ice observers onboard disagreed.
To identify the target, the plane descended to a mettle-testing 100 metres. This was both part of the mission and what the hundreds of ships that cross this relatively small part of the ocean demand of the staff of the International Ice Patrol.
Ever since the Titanic struck one of more than 350 icebergs drifting in north Atlantic shipping lanes in April 1912, the U.S. Coast Guard has undertaken annual patrols to protect passenger and freight vessels that sail the congested waters east of Canada and the United States.
"Before we started, there were 113 recorded sinkings caused by icebergs," says Michael Hicks, Commander of the International Ice Patrol (IIP). "There have only been 19 since the Titanic sank, and all of those were vessels that chose to ignore our warnings."
In the past, in a single year, more than 2,000 icebergs have been spotted and on occasion ineffectually bombed to prevent disasters at sea.
Yet in other years, including this one, few if any bergs manage to migrate south of the Arctic Circle.
If the unidentified floating object below the plane is an iceberg, it'll be the first one seen in the shipping lanes since May 2005, a situation perplexing to oceanographers but emboldening to those shouting about the effects of climate change.
"I've been trying to understand the variability for years." says Don Murphy, the IIP's veteran oceanographer. "And every year that goes by I get another year of experience and realize how little we really know."
After a century of study, there are still many unknowns in the movement of icebergs and the wide variability in the number that mischievously make it into the 500 kilometre-long, 100-kilometre-wide area of the North Atlantic that mariners refer to as 'iceberg alley' due to the number of bergs pushed through by currents and underwater topographical features.
What is certain is that for any that do make it this far south, they will be nearing both the end of a three-year journey and their existence.
The warm waters of the Gulf Stream ultimately melt all icebergs ensuring one less threat to ships.
What formed from 1,000-year-old ice atop the majestic ice cap in Greenland ends up becoming an indistinguishable part of the ocean.
The International Ice Patrol, a division of the U.S. Coast Guard, is the only world body (funded by 17 countries) that constantly monitors icebergs that stray into the Atlantic shipping lanes parallel to and south of Newfoundland.
While the Canadian Ice Service is dedicated to monitoring sea ice in Canadian waters and the Danish Meteorological Service is concerned with bergs around Greenland, the IIP has, since its inception in 1912, been charged with alerting cross-Atlantic traffic to any iceberg threats.
"Almost immediately after the Titanic sank, the U.S. Navy assigned two cruisers to the Grand Banks to let the ships know were the icebergs were." says Hicks.
"The following year the U.S. Navy could no longer spare the ships to do that so the Revenue Cutter Service, the predecessor to the Coast Guard, stepped up. The U.K. asked the U.S. government to continue and, with the exception of the war years, we have been doing it ever since."
The International Convention for the Safety of Life at Sea (SOLAS), a major treaty governing merchant ships, mandates that all vessels crossing the North Atlantic during the months when there is a threat from icebergs (usually February to July) receive and read the IIP's notifications.
However, they are not compelled to act on them, hence the 19 sinkings that have occurred since 1913.
An iceberg (technically a piece of ice longer than 14 metres at the waterline) has to make it past 48 degrees north before the IIP counts it as having the potential to interfere with shipping (the Titanic sank just south of 42 degrees north, and icebergs have been spotted in waters as far south as those parallel to Washington D.C.).
Surprisingly it wasn't until 1946 that the Coast Guard started using aircraft to supplement its ships in the search for these monstrous and potentially lethal pieces of ice.
"Up until that time it was just cutters," says Hicks. "Generally they would assign two or three cutters and they would take turns going out from Halifax or St. John's, finding the southernmost iceberg and staying with it and radioing their position to ships coming across the Atlantic."
The IIP stopped using ships in 1973, relying on airplanes.
"The C130 aircraft can cover a much larger area in a lot less time," says Hicks. "They also have the capacity to carry side-looking radar, which is old but very effective. It was designed to detect oil spills but it works pretty well for icebergs."
The planes do 12 or more missions a month and fly for six to eight hours at an altitude of 1,800-2,800 metres yet because of the weather, even at that height, the sea is visible only 30 per cent of the time.
"We will descend to as low as 100 metres if we detect a target on the radar that we can't identify and the cloud base is low." Hicks says. "Hopefully we will see the surface by that point."
Once an iceberg has been detected, its size and location are plotted on a map marked with the limits of all known ice. The map is then disseminated to all ships crossing the Atlantic (more than a dozen a day) and posted on the IIP's website.
To ensure a margin of safety, the line depicting the limits of all known ice is usually drawn 50 kilometres south of the actual last known position of an iceberg.
When the planes aren't flying, the maps are still updated every 24 hours.
"We forecast where we think the bergs are going using a computer model," Hicks says. "That model uses ocean currents, winds, water temperature and waves to predict where the iceberg is going to drift and how long it is going to take to melt." He admits the model is not flawless.
"In the short term it does a pretty good job. But as you go beyond six or seven days it becomes less reliable, just like a weather forecast, so that's why we patrol so often." Icebergs generally drift no more than 20 kilometres a day.
With most of this year's ice season over, not a single berg has been seen within 500 kilometres of the shipping lanes. Only once before, in 1966, has the IIP recorded zero icebergs in a season. There's no question the low number is unusual.
"On average we expect to see about 450 icebergs a year," says Don Murphy who explains all icebergs in the North Atlantic are produced by ice flowing slowly but steadily from glaciers in Greenland into the sea and breaking away.
The floating chunk of ice is then at the mercy of ocean currents that carry it northwards and then westwards across to Baffin Bay before the Labrador Current pushes it southwards.
"The currents are weak and variable along Baffin Island so every iceberg's southward track is characterized by long periods of no motion," says Murphy.
"Most will go aground on a pinnacle or submerged mountain around the edge of the continental shelf and you have to wait for them to deteriorate until finally they can float off the bottom and can continue their path.
"Then Boom! They get stuck again or get driven so far into a bay that they never make it out and waves destroy them."
Murphy says the ones that do make it -- less than 1 per cent of all the bergs produced annually -- are "the ones with a shape that ensures they aren't as sensitive to the wind's effects, so they stay offshore or have enough mass that even if they are grounded for awhile, then, when they float again, they are large enough that they still bring a substantial mount of ice with them."
The icebergs that survive all the way from the glaciers to the Grand Banks take up to three years to make the 2,500-kilometre journey. Once there, they'll be tracked by the IIP and left to disintegrate into the ocean. However, shortly after the Titanic sank and up until the 1960s, there was a belief that icebergs could, and should, be destroyed.
"It was thought that if you shot a shell at an iceberg that the ice was so brittle that it would just disintegrate," Murphy says. "The U.S. Navy attempted it, but all they did was loosen a basketful of ice. Then they decided to float mines against the sides of the bergs and blow them up, but that didn't work either."
Further attempts were made after the Second World War using larger bombs. "They arranged to drop 20 1,000-pound bombs on an iceberg. They hit it 17 times over a six-day period but the end result was an insignificant change in the size of the berg, so they gave up. It was a silly idea and it was abandoned; the ocean does the job perfectly."
Icebergs always succumb to warm water and warm weather, but now there is considerable debate as to whether climate change is playing any part in the fate or future of these floating photogenic white sculptures.
"There is no doubt in my mind major climate change is happening," says Murphy, who has been an oceanographer for 22 years.
"Studies in Greenland show glaciers are moving twice as fast as before. That means a lot of production of ice. My expectation has always been if the Greenland glaciers started moving faster, there would be increased production (of icebergs) for decades and there should be an increase in the number of icebergs into the shipping lanes.
"That was my model. But the last couple of years that hasn't happened and I'm having a hard time understanding what is going on except that there are complicating factors having to do with increased storms.
"Maybe the destruction processes dominate over the production processes."
The main destruction process is wave action. Icebergs that run aground are the most vulnerable to sustained wave attack. In past years large concentrations of sea ice have been thought to help icebergs remain afloat and prevent erosion from waves.
In 2005, according to the U.S. National Snow and Ice Data Centre, sea-ice cover was at its lowest extent since satellite monitoring began in 1979 and this year the IIP have noticed "very little -- although not an absolute minimum" level of sea-ice conditions. Yet a computer model linking sea-ice levels to the number of icebergs making it into the shipping lanes has performed 'horribly,' according to Murphy.
So while climate change could be expected to bring about an increase in the number of icebergs being forced into the ocean, its effect in reducing the level of sea ice through increased sea temperatures could equally mean that those icebergs liquefy long before they reach any areas of concern.
Yet, Murphy points out, that does not explain the huge discrepancy in the number of icebergs recorded in years before climate change was considered an issue - e.g. 15 icebergs in 1952; 1,500 in 1972.
After thoroughly studying and analysing data from as far back as 1900, Murphy can find no significant or consistent pattern in the number of icebergs making it into the shipping lanes.
"It's a very complicated system and there are a lot of moving parts," he says, but he claims some people are eager to ascribe meaning to the figures.
"Back in the mid '90s when we had thousands of icebergs I got a call from Japanese TV who wanted to do a story on us because they believed the large number of icebergs was indicative of global warming," he says.
"Then, in 1999 we had only 22 icebergs and I got a call from a European TV company who wanted to a story because they were certain that the fact that there were only 22 bergs in the shipping lanes was a clear indication of global warming."
Murphy himself is reluctant to draw any conclusions from the ever changing number of icebergs.
Commander Hicks also believes the century-long variability precludes blaming climate change for the present low numbers.
"There would have to be a decade of consistently light or consistently heavy years to say something is happening here and we haven't seen that," he says.
Nevertheless, only 11 icebergs were spotted in the shipping lanes last year and they remain even more elusive this year.
This makes the debate on board the low-flying C130 all the more intense. As the plane continues its descent through the clouds, seagulls are spotted atop the floating white object.
At 100 metres above the churning ocean, when the flight crew and the ice observers can all see the object in detail through thick Plexiglas windows, they realize it is, disappointingly, an inverted, dead Northern Right whale.
"We'll keep looking," says Hicks. "We know there are icebergs out there and maybe some will make it south before July."
If they do, the International Ice Patrol will certainly count them, but they'll leave it to others to decide the significance of the number.
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