Icebergs: Uncovering the giants
TORONTO – Living in the Great White North means that we see lot of snow and ice — even in the summer months.
After months of cold weather in the northern hemisphere, sea ice melts, often resulting in the journey of icebergs from the far north and Greenland. For the shipping industry it means big headaches. But for communities in Newfoundland and Labrador, icebergs mean tourism.
And luckily for them, Newfoundland and Labrador has seen a higher number of icebergs off its shores this year.
Why are we seeing more icebergs?
“There has been a little bit more [ice] melt than average,” said Walt Meier of the National Snow and Ice Data Center in Bolder, Colorado. “Things are clearing out a little bit faster than normal, but not as extreme as in some years.”
This is one factor that has led to more icebergs being spotted off the coast of Newfoundland and Labrador. But, Luc Desjardins, Senior Ice and Iceberg Forecaster for the Canadian Ice Service said that it is just one of many factors contributing to the increase.
Because it can take a year or more for the icebergs to reach Canadian waters, weather patterns are greatly responsible for the direction that the icebergs travel. If there is a storm (or storms) that push into the area, it will cause icebergs to head to coastal areas where people can observe them. Other years, it might push the icebergs further south.
“It’s what took place many years ago that has led to this particular crop this year off the Newfoundland waters… Had the prevailing winds and water currents had been a little bit more off shore this year, none of them would be in the location they’re in right now. And people would have said, ‘We haven’t seen icebergs this year. Why’s that?'”
“We are seeing more in the southern Newfoundland waters like the Straight of Belle Isle and along the St. Anthony coast or the northern peninsula. But we’re not seeing as many in St. John’s region.”
How do icebergs form?
You might be surprised to discover that all icebergs form on land.
Icebergs come from glaciers which formed over thousands of years of snowfall. The snow falls and, over time, layers form. The layers press down, compacting the layers beneath. Glaciers continue to move, downward and outward in all directions. And as they move, they may head out to open waters. It is there where the life of icebergs begin.
Pieces of the glaciers “calve” or break off. Calving also occurs on the larger icebergs as they move along their journey.
Icebergs are slightly flexible, but when the waves come in — not the waves we see on the surface, but ones farther down below — they can cause more brittle parts of an iceberg to break, causing them to calve further, sending more pieces out into the ocean.
The glacier responsible for the most recent spate of icebergs is the Petermann Glacier in Greenland. This massive ice sheet has produced many of the icebergs that have travelled through Canadian waters.
“Right now we’re seeing several smaller chunks of the massive ice island that broke off the Petermann chunks in the southern Labrador-northern Newfoundland waters. And these smaller chunks, but still huge…they’re almost little floating glaciers and they’re actually calving and there’s a piece that breaks off every so many days or perhaps several times a day, depending on the stormy weather that hits the area,” said Dejardins. “And what happens is you find yourself surrounded by way more icebergs in that particular area than you’d normally find in a typical non-Petermann massive chunk calving event that occurred in the years prior.
“There are still pieces of the Petermann calving event from 2010 that are still alive and kicking and they are trapped in the coastal ice along the Baffin Island coast…and there are also pieces of the 2012 trapped in the shallow waters along the Baffin Island coast and they may remain there for perhaps another year before they lose sufficient mass to float up and continue their journey.”
Younger icebergs appear blue; older ones more like the solid piece of snow most people tend to think of.
And, though the icebergs we see are huge, it’s what lies below that can be mind-blowing.
“What you see above the waterline is about 10 to 15 per cent,” Meier said. “So it’s about 85 to 90 per cent is below.”
Is this a sign of global warming?
There is no doubt that the Arctic is seeing less sea ice than it has in recorded history.
“We’ve lost over 40 per cent of summer ice cover,” Meier said. “We’ve also seen significant decline in the ice sheet in Greenland.”
And this reduction can have significant impacts on the global climate. The sun’s energy reflects off the sea ice and melts ice.. But when the ice melts, the ocean doesn’t reflect as much of that energy out and warms the oceans. Then that can heat up the atmosphere. It’s what Meier calls a “positive feedback loop.”
When it comes to climate change, Desjardins believes it’s part of a bigger picture.
“It may mean drier weather and forest fires in Quebec…it may be a flood in the Prairies. It affects different areas in different ways. But surely it has an effect on the Greenland glaciers.”
© Shaw Media, 2013