As icebergs drifted through his Antarctic-bound ship, David Holland spoke this week about how the melting glacier to which he sails could contain warning signs for the coast of distant Canada.
The atmospheric and oceanic scientist from Newfoundland is part of an expedition to one of the world’s most icy and remote places – the Thwaites Glacier in the western part of the continent – where he will measure water temperatures in a submarine canal as large as Manhattan .
“The question of whether sea level will change can only be answered by looking at the planet where it matters, and that is at Thwaites,” Holland, director of the Environmental Flow Dynamics Laboratory at New York University, said during a satellite telephone interview from aboard the South Korean icebreaker Araon.
Read more:
‘Historic’ Halifax sea wall is being redeveloped as municipality seeks to reduce the impact of climate change
It is more than 16,000 kilometers from Holland’s hometown in Brigus, NL, on Conception Bay, to the site about 100 kilometers inland from the “land zone” where the Thwaites’ glacier leaves the mainland and stretches across the Pacific Ocean.
The team’s 20,000 tons of drilling equipment will be assembled to measure the temperatures, salinity and turbulence of the Pacific waters that have crept under and flowed away at the bowels of the glacier.
“If it (the water) is above freezing, and in salt water it means above -2 degrees Celsius, it is not sustainable. A glacier can not survive it, ”said Holland.
Since 2018, more than 60 scientists from the International Thwaites Glacier Collaboration group have been exploring the sea and marine sediments, measuring warming currents flowing into the deep ice, and examining the stretch, bending and grinding of the glacier across the landscape below.
The Florida-sized Thwaites Glacier looks at the Amundsen Sea, and researchers have suggested in journal articles over the past decade that it could eventually lose large amounts of ice due to deep, hot water being driven into the area as the planet warms. Some media have dubbed Thwaites the “doomsday glacier” due to estimates that it could contribute about 65 centimeters to global sea level rise.
Holland takes note of current research models mainly suggesting that this would happen in a few centuries, but there are also lower probability theories of “catastrophic collapse” taking place, where the massive ice shelf is melting in the span of decades. “We want to pay attention to things that are plausible, and rapid collapse of that glacier is a possibility,” he said.
While Holland looks at the submarine meltdown, other scientists are investigating how the land-based portions of Antarctic glaciers are losing their grip on points of attachment to the seabed, possibly causing parts to loosen. Still other researchers point to the risk of initial fractures causing the ice bank to break, much like a damaged car windshield.
Read more:
Sea whale damage is a sign of things to come amid rising sea levels and climate change, experts warn
All of the mechanisms need to be carefully observed to prove or disprove models about the melting rate, Holland said.
“If the (water-filled) cave under the glacier we study becomes larger, then Antarctica is losing ice and retreating, and if the cave collapses on itself, (the cave) will disappear. “This is how Antarctica can withdraw, these kinds of specific events,” he said.
The implications of the glacier work stretch back to Atlantic Canada – which, along with communities along the Beaufort Sea and in southwestern British Columbia, is the region most vulnerable to rising sea levels in the country, according to federal scientists.
Everything from how to calculate the future elevation of dikes at the low-lying Chignecto Countryside – the narrow band of land that connects Nova Scotia to the rest of the country – to whether the Fraser River lowlands may face floods, is made possible by glacier melting in Antarctica, he said.
Scenarios where Antarctic ice is melting faster than expected are briefly discussed in the 2019 federal report Canada’s Changing Climate. The 2019 report was largely based on reports from the Intergovernmental Panel on Climate Change which referred to them as theories with a low probability “tip”, the possibility of a one meter sea level rise by 2100.
However, Blair Greenan, a federal oceanographer who oversaw the relevant chapter of the report, said in a recent interview that a rise in global sea levels approaching two meters by 2100 and five meters by 2150 “cannot be ruled out” not “due to uncertainty about ice sheet processes such as Thwaites.
“We do not know, no one knows,” Holland said. “But it’s plausible that these things could change, and a few feet of sea level change would have a big impact on Atlantic Canada. What is needed is glacier forecasting that matches the kinds of accuracy that weather forecasting currently offers.”
However, the collection of glacier forecast data is a daunting undertaking in the short period – from late January to mid-February – when scientists can safely take lectures. Helicopters will transport a hot water drill, 30 barrels of fuel and water to Holland’s site from the end of January. The drill will have to penetrate over a kilometer of ice to reach the 300 meter submarine canal to take measurements.
As the data is collected, some scientists are questioning whether there really is much that Canadian coastal dwellers should be concerned about at this stage.
One study by Ian Joughin, a glaciologist from the University of Washington, suggested that Thwaites would only lose ice at a rate that caused sea level rise of one millimeter per year – and only next century. At that rate, it will take 100 years for sea levels to rise 10 centimeters.
In a telephone interview last week, Joughin said planning coastal protection and other measures for the more extreme scenarios may not be cost-effective at this stage, as it could take up to a century before the major risks begin to unfold.
However, Joanna Eyquem, a Montreal-based geoscientist who studies ways to prepare infrastructure for rising sea levels, said in a recent email that glacier research shows that sea level forecasts are “constantly evolving”, and adaptation efforts need to be faster.
“The question is: How desperate must the situation be before we act?” she asked.
This report by The Canadian Press was first published on January 23, 2022.
© 2022 The Canadian Press
Reference-globalnews.ca