Scientists have long known that glaciers are melting and contributing significantly to sea level rise. What’s not fully understood, however, is the complex ways they are moving deep within, a process critical to understanding this melting.
Now, two MIT researchers said they have created the first usable model to analyze movements across the Antarctic Ice Sheet, looking at how ice flows in the glacier’s core, according to a study published on May 30 in The Proceedings of the National Academy of Sciences.
The implications are massive: a critical step in understanding the potential speed and severity of sea level rise, the researchers said. The keys to unlocking all of this can be found at the microscopic level with glacier flow, the study reported.
“We really need to better understand how ice works on a really small scale, in order to understand how ice sheets are going to change on a large scale,” said Meghana Ranganathan, the first author of the study.
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Glaciers themselves are a “river of ice,” said Brent Minchew, the second author of the study. The ice inside the glacier flows like “honey,” he said.
“If you pour honey on a plate, it spreads out over the plate, and ice behaves in much the same way,” Minchew said.
Glacier flow refers to the process of glaciers deforming when they are under “stress,” Minchew said, and defects or deformations will always exist. Glacier flow is “by far the dominant component” in sea level rise, he said.
“The flow of glaciers is really the thing that could lead to catastrophic sea level rise scenarios,” said Minchew, also an associate professor of geophysics at MIT. “It’s entirely possible that we could get up to two meters of sea level rise by the end of the century, which would be a global calamity. It would displace at least hundreds of millions of people.”
The study, which took the two researchers about three and a half years to complete and publish, becomes increasingly relevant as the climate continues to warm and “glaciers are speeding up in response,” Minchew said, making glacier flow, sea level rise, and climate change inextricably linked.
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The researchers created their model based on two specific deformation mechanisms — dislocation creep and grain boundary sliding, the study said.
Using decades of research in the field, they applied past experimental data to analyze current movement within the Antarctic Ice Sheet, said Ranganathan, who was a PhD student at MIT when completing the study.
“The study that we’re focused on takes a really big and important step toward understanding what the future is going to look like,” Minchew said.
Ginny Catania, a senior scientist at the University of Texas at Austin, said the study looks inside the glaciers, making observations the scientific community “hasn’t ever heard before.”
“This is actually saying to most of us that there’s a lot happening in the ice itself that can be really critical,” Catania said. “It’s really important, which is why it got published in this journal.”
However, long term, Catania said the model needs to be tested. She hesitated to say any predictions of sea level rise can be concrete.
“We don’t know which of these models might be correct,” Catania said. “We also don’t know how humans are going to behave.”
But communities, especially those on the Massachusetts coast, need to be ready for sea level rise even if it’s a “huge question mark” on what the changes will look like, she said.
“We need to take seriously the fact that our coastline is going to look dramatically different for future generations and how do we plan now for that kind of change for our grandkids and their grandkids?” Catania said.
Minchew, who recently started a nonprofit called Arête Glacier Initiative to tackle the challenge of rising sea levels, is now asking broader questions: “What can we do about it? We can’t just sit by and let half a billion people lose their homes,” he said.
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For Ranganathan, who will start as an assistant professor of geophysical sciences at the University of Chicago on July 1, she plans to continue to perfect the model with more factors — ice temperature, the size and the orientation of individual ice crystals, whether the ice is fractured, or whether it’s completely intact.
“What’s exciting about science is that you almost always go in a different direction from when you started, which is always a good thing,” she said.
Ava Berger can be reached at ava.berger@globe.com. Follow her @Ava_Berger_.