Linda Welzenbach / Courtesy photo
Tasha Snow / Courtesy photo
There’s no question that ice is flowing rapidly out of western Antarctica’s Thwaites Glacier, threatening to contribute to dangerously rising sea levels in coming decades that could swamp cities and irrevocably upend the lives of people around the globe.
The key uncertainties surrounding the dynamic now unfolding there and making the region something of a glaciology wild card, are simple; how much, and how fast?
Scientists believe that between the Thwaites Glacier and neighboring Pine Island Glacier, the amount of ice that could funnel out of them and into the Amundson Sea combined could lead to 3 meters of sea level rise; the Thwaites Glacier by itself could produce 80 centimeters of sea rise.
Several researchers at the University of Colorado Boulder are part of the International Thwaites Glacier Collaboration, a five-year international effort to study every aspect of what is happening at the 74,000-square-mile glacier that launched April 1, 2018, and is currently funded through March 31, 2023.
CU Boulder doctoral candidate Tasha Snow sat down Thursday, along with one of her advisors, CU Cooperative Institute for Research in Environmental Sciences senior research scientist Ted Scambos, to discuss the ongoing project, a partnership jointly supported by the National Science Foundation and the United Kingdom’s Natural Environment Research Council.
Snow returned March 27 from a two-month stint at Thwaites Glacier aboard the icebreaking research vessel Nathaniel B. Palmer. Scambos was most recently down in the region — his nineteenth trip to Antarctica — in November and December.
“It’s the most incredible place in the world,” Snow said of Antarctica, which she has now visited three times. “It’s one of the few untouched frontiers in the world. I’m a person who loves to observe and experience a place in its natural state.”
The front of the Thwaites Glacier stretches for about 120 kilometers.
“The location we went to in front of Thwaites Glacier, no one has been before, no one has mapped that area before, ships have never been in some of the locations that we went to,” Snow said.
“There have been ships that have been nearby, but there is an entire area that has never been mapped, no bathymetry (sea floor mapping), no ocean measurements, no anything, before.”
In addition to Scambos and Snow, Betsy Sheffield, a professional research associate from CU Boulder’s National Snow and Ice Data Center, is project coordinator for the project’s Science Communication Office. Bruce Wallin, a professional research assistant from NSIDC, and various individuals in the CU Engineering department are also involved with instrument programming and development for one of the specific projects that are part of the initiative.
Precedent for a feared scenario
Scambos is co-principal investigator on the project’s Science Coordination Office, the primary mission of which is to coordinate the initiative’s eight funded research projects, which in the acronym-happy world they inhabit, are known by colorful monikers including THOR, PROPHET, GHOST and TIME.
Scambos said, “There are precedents in the record of sea level rise, where we have had a meter of sea level rise, within a century — actually, even more than that — and nobody is quite sure how and where that ice came from. But now it seems like we’re beginning to identify the processes that could lead to something like that. And maybe that is going to play out on Thwaites Glacier.”
He was referencing what is known to scientists as Meltwater pulse 1A, estimated to have occurred between 13,500 and 14,700 years ago.
“That’s the most rapid sea level rise that’s accurately dated in the geologic record. And it was right at the end of the last Ice Age,” Scambos said. “At the end of the last ice age, we saw events that would be disastrous if they played out in the present-day world. And that’s the kind of thing that’s lining up, or we think could be lining up, with Thwaites Glacier.
“And it’s not just Thwaites. There are other areas of Antarctica that appear to be capable of this sort of thing.”
And because ice sheets such as Antarctica lose some of their gravity as they shed their mass, the ice they lose converts into sea level rise that pushes north. That means coastlines in the Northern Hemisphere — including the United States — would be most severely affected.
Individual studies under the overall project umbrella are examining separate questions, but data and findings will be integrated, with teams coordinating their research efforts.
On Snow’s recent southern stint, three of the projects were represented. They were THOR (focusing on offshore research), TARSAN (a ship-based project studying how atmospheric and oceanic processes are influencing the behavior of the ice shelves) and GHC (which is gathering information about past ice sheet behavior and relative sea level change in the Thwaites Glacier system).
The level of collaboration between teams on the most recent research cruise, Snow said — specifically, pioneering mapping of the ocean floor by the THOR team — enabled the TARSAN group’s scientists to put a $4 million unmanned submersible vehicle under the floating portion of the ice shelf a full year ahead of schedule.
“We’re bringing groups together to kind of synergize the science being done, to get a lot more out of the research than what would be done, if any of these groups did it by themselves,” Snow said.
“And that’s what played out on this cruise. Everybody felt they had got more out of it than they expected to get. It really lays the groundwork for the next years’ research that are going to happen.”
The study is currently funded at a level of $50 million to $60 million, and will ultimately involve 80 to 100 scientists, with 30 to 40 going down each research season.
The size of the Thwaites Glacier has been likened to Great Britain and the state of Florida. Scambos prefers a comparison to Idaho, because, although Idaho is a little larger, it is vaguely similar in shape.
For Coloradans, he likes to compare it to the area of the state west of the Continental Divide, with the front of the glacier equating to about the span from Denver to Fort Collins.
“Is that area between Denver and Fort Collins going to move fast enough to empty most of that whole Western Slope within the next 50 to 100 years?” he asked, extending the comparison of the melting glacier. “It’s still a little mind boggling.”
He noted that a glaciologist in 1990, based on observations made at that time, would not have bet on such a dire scenario.
But since the start of this century, Scambos said, “We began to see several areas light up, so to speak, thinning faster, with lots of flow, lots of calving (of icebergs) and some processes that we’d never seen before, like breakups of ice the size of Boulder County in just a few weeks. So it’s a little hard to imagine, as a human being. But as a scientist who has watched the progression of change over the last 30 years or so, I don’t want to rule it out.
“Because, the consequences are too great and the models are there, saying, this looks like it could really take place.”