A mere thousand feet above the frigid waters of the North Atlantic the debate began in earnest. The pilot of the U.S. Coast Guard's sturdy C130 plane believed the object which had appeared on both of the plane's radars was an iceberg. One of two young but experienced ice observers onboard disagreed.
To definitively identify the target, the plane started to descend to a harrowing 400 feet. This is what hundreds of ships that traverse this relatively small part of the ocean continually demand of the staff of the International Ice Patrol.
Ever since the Titanic struck what was actually one of more than 350 icebergs drifting amidst the northern Atlantic shipping lanes in April of 1912, the Coast Guard has undertaken annual iceberg patrols to help protect passenger and freight vessels that sail through the congested waters east of Canada and down the east coast of the United States.
International Ice Patrol
"Before we started there were 113 recorded sinkings caused by icebergs," said Michael Hicks, commander of the International Ice Patrol. "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, tracked and on occasion ineffectually bombed by aircraft, in order to prevent disasters at sea. Yet in other years, including 2006, few if any bergs manage to migrate south from the Arctic Circle. If the unidentified floating object below the plane on patrol last year was in fact an iceberg, it would have been the first one seen in many months, a situation perplexing to oceanographers but emboldening to those shouting loudly about the effects of climate change.
"I've been trying to understand the variability for years," said Don Murphy, the Ice Patrol's veteran oceanographer. "And every year that goes by I get another year of experience and realize how little we really know."
MANY UNKNOWNS
After a century of study, there are still many unknowns regarding the movement of icebergs and the reasons for the wide variability in the number that mischievously make it into the 300-mile-long and 60-mile-wide area of the North Atlantic known as "Iceberg Alley." What is certain is those that do make it this far south are nearing the end of a three-year journey and their existence.
"When the bergs get this far south, their days are numbered," Hicks said, explaining that the warmer waters of the Gulf Stream cause all icebergs to ultimately melt, ensuring one less threat to ships and one less iceberg for the patrol to monitor. What formed from 1,000-year-old ice atop the majestic ice cap in Greenland ends up becoming an indistinguishable part of the ocean and a sterile statistic in the Coast Guard's table of meddlesome bergs.
International Ice PatrolIce must be longer than 45 feet at the waterline to be considered an iceberg. This shape is known as tabular ice.
The International Ice Patrol is a unique organization. A division of Coast Guard, it 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 and icebergs in Canadian waters, and the Danish Meteorological Service is concerned with bergs around its territory of Greenland, the International Ice Patrol 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 patrol for icebergs," Hicks said. "The following year, the U.S. Navy could no longer spare the ships to do that, so the Revenue Cutter Service, which was the predecessor to the U.S. Coast Guard, stepped up. The U.K. actually asked the U.S. Government, since we had started doing this, to continue and, with the exception of the World 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 Ice Patrol's notifications. However, they are not compelled to act on them, hence the 19 sinkings that have occurred since 1913.
An iceberg, which is technically a piece of ice longer than 45 feet at the waterline, has to make it past 48 degrees north – a line of latitude that passes through northern France in Europe – before the Patrol 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.
AIRCRAFT SPOT WHAT SHIPS CANNOT
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.
International Ice PatrolPatrols now made by plane were once made by ship.
"Up until that time it was just cutters," Hicks said. "Generally they would assign two or three cutters and they would take turns going out from Halifax or St. Johns, finding the southern most iceberg and staying with the iceberg and radioing their position to ships coming across the Atlantic."
In 1973, the Patrol stopped using ships and has relied on airplanes ever since.
"The C130 aircraft can cover a much larger area in a lot less time," Hicks said. "They also have the capacity to carry side-looking airborne radar, which is an old but very effective radar system. It was designed to detect oil spills but it works pretty well for icebergs."
The planes, which conduct 12 or more missions each month, normally fly for six to eight hours at an altitude of between 5,500 and 8,000 feet. Yet because of the weather, even at that height, the sea is visible only 30 percent of the time.
"We will descend as low as 400 feet if we detect a target on the radar that we can't identify and the cloud base is low," Hicks said. "Hopefully we will see the surface by that point."
International Ice PatrolA bomb crater after the U.S. Navy's failed experiment to blow up icebergs using airborn bombs and floating mines.
Once an iceberg has been detected, its size and location are plotted onto a map, which is marked with all known ice. The map is then disseminated to ships crossing the Atlantic – there are more than a dozen each day – and is posted on the Patrol's website. To ensure a margin of safety, the line depicting the limits the ice is usually drawn 30 miles 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 said. "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."
Hicks acknowledges that the model is not flawless.
"In the short term it does a pretty good job," he said. "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."
Studies show that icebergs generally drift no more than 12 miles in a day.
450 ICEBURGS A YEAR
Only once, in 1966, had the Patrol recorded zero icebergs in a season - until last year. In 2006, the number of icebergs sighted past 48 degrees north, and therefore inside shipping lanes, was again zero, according to the Patrol's annual report. This is a stunning change, given that in 2003 there were 927 icebergs on record.
"On average we expect to see about 450 icebergs a year," said Don Murphy, the oceanographer, who explains that all of the icebergs that appear in the North Atlantic are produced by ice flowing slowly but steadily from glaciers in Greenland into the sea and breaking away. The floating chunks of frozen water are then at the mercy of ocean currents, which initially carry them north and then west across to Canada's Baffin Bay before the Labrador Current pushes them south.
"The currents are weak and variable along Baffin island so every iceberg's southward track is characterized by long periods of no motion," Murphy said. "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 that the ones that do make it – less than one percent 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 a while, then when they float again they are large enough that they still bring a substantial amount of ice with them."
BLOWING UP BERGS
Those icebergs that survive all the way from the glaciers to the Grand Banks take up to three years to make the 1,500-mile journey. Once there, they will be tracked by the Patrol and left to disintegrate into the ocean. However, from the time the Titanic sank up until the 1960's, 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 said. "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 World War II, 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."
International Ice PatrolIcebergs travel thousands of miles over several years, degrading as they go. This shape is non-tabular.
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," said Murphy, who has been a professional oceanographer for 22 years. "Studies in Greenland show that the 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 Center, sea ice cover was at its lowest since satellite monitoring began in 1979, and in 2006 officials at the International Ice Patrol 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 mean that those icebergs liquefy long before they reach 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 (there were 15 icebergs in 1952 and 1,500 in 1972). After thoroughly studying and analyzing 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.
CLIMATE CHANGE
"Back in the mid 90's 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."
International Ice PatrolThe tallest iceberg on record is 550 feet.
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 said. Nevertheless, only 11 icebergs were spotted in the shipping lanes in 2005.
This made last year's debate on board the low-flying C130 all the more intense. As the plane continued its descent through the clouds, seagulls are spotted atop the floating white object. At 400 feet 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," Hicks said. "We know there are icebergs out there."
Michael Park has contributed to The Sunday Times Magazine, The Independent, and The Herald.