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The problem is clear: the world’s glaciers are melting, causing sea levels to rise.
As global temperatures soar due to the continued influx of greenhouse gases trapped in the Earth’s atmosphere, melting glaciers are adding more water to the oceans. Sea level rise is projected to encroach on coastlines, affecting communities and ecosystems. As a result of this human-caused climate change, global rates of sea level rise have been unprecedented over the past 2,500-plus years.
An inundation of freshwater in the ocean would also affect the ocean’s currents, which depend on a delicate balance of salinity, density, and temperature to churn and regulate Earth’s climate.
To address these concerns, scientists are developing mitigation and adaptation strategies that they think could help save us and the glaciers — large sheets of ice and snow found on every continent but Australia — from worsening impacts. But, right now, these measures are largely theoretical.
“Just as many humans take supplements to counter bone mass loss after a certain age, there may be low-cost, low-impact, logistically simple methods to counter ice sheet mass loss,” Dr. Ken Mankoff, senior scientific programmer at New York’s NASA Goddard Institute for Space Studies, told The Independent via email on Thursday. “It’s worth exploring if this is possible.”
Ocean heat-blocking
One approach would be to stop warm ocean water from flowing underneath the Antarctic ice shelves using giant curtains or submarine seawalls to hold it back.
Although, what exactly the curtains would be made out of has yet to be determined. Scientists told Grist last year that they could potentially use air as that barrier, pumping it from a pipe drilled with holes.
Controlling glacier friction
A second idea is increasing the friction between glaciers and the rock that’s below their ice in order to slow them down, as they naturally begin to slide out or down under the pressure of their own weight.
This strategy would pump water either into or out of the cracks between the ice and the Earth’s rocky crust to control that friction and potentially slow down a glacier’s movement.
Thickening the ice
A third method shared by Douglas MacAyeal, professor emeritus from the University of Chicago’s Department of Geophysical Science, is to pump water on parts of the Antarctic ice sheet in the winter.
The water would then freeze over and thicken the ice to the point where it would also increase the friction, making the ice shelves so thick that they can’t even move over bays.
He explained that the various proposals on the table are based on our understanding of how glaciers in Antarctica and Greenland naturally change, as they move in response to gravitational forces and stress. Still, scientists don’t yet know if these ideas would be enough to stop the melt of something like the Thwaites “Doomsday” Glacier. That glacier alone is responsible for about a percent of global sea level rise.
“Could we really do that?” he wondered. “Even though, we know other glaciers have been stopped in the past by changing water at their bed or by the fact that there’s different oceanographic heat fluxes to their grounding lines.”
Ocean heat-blocking interventions — including the curtain or seawall — have the most research, Dr. Michael Wolovick, postdoctoral researcher at the Alfred Wegener Institute for Polar and Marine Research, explained via email. He believes that they’re “probably the most likely to be effective.”
“Whole-planet interventions like stratospheric aerosol injection would also benefit the ice sheets, although they would probably have a bigger immediate impact on Greenland than Antarctica, because Greenland loses more mass to surface melt at the present day,” he noted.
Sulfate aerosol injections
Aerosol injections, shooting particles made of sulfur compounds into the air like a volcano does, may lower the Earth’s temperature by reflecting away solar radiation. However, the wider implications of that plan are worrying.
But while theories are abundant in glacial engineering, making them a reality would prove difficult.
It would take decades to make the necessary measurements to understand what it would actually take to perform such interventions, Slawek Tulaczyk, a glaciologist at UC Santa Cruz, and Wolovick both pointed out.
“It is important to keep in mind that we still have a great deal of uncertainty, but despite this uncertainty, we still need to make decisions and act,” Wolovick said.
Glaciers are expected to undergo major changes in the coming decades. Two-thirds of glaciers are slated to disappear by 2100, according to a 2023 study published in the journal Science. More than 400 billion tons of ice have already been lost since the mid-1990s.
But for some scientists, these long-term projects carry risks — including potential impacts on the climate — that aren’t worth taking.
“They tend to be very difficult to scale. They often involve extensive resources and additional emissions themselves,” said Dr. Twila Moon, Deputy Lead Scientist and Science Communication Liaison at the National Snow and Ice Data Center. “Many of them are likely to have unintended consequences for the environment or may even alter the ice, be it the glacier or sea ice surface, in ways that can actually exacerbate the problem.”
Moon cited the end of the non-profit Arctic Ice Project that was experimenting with using silica beads to slow ice melt in the Arctic. Testing revealed that the plan had “potential risks to the Arctic food chain,” but the group blamed a “broad skepticism toward geoengineering” for its decision to shut down.
“And, I think for myself and many in the glaciology scientific community, we’d really like to see folks focusing on mitigation and successful adaptation,” Moon said.
Jeremy Bassis, a professor at the University of Michigan, told The Independent that he believes geoengineering is “never going to play a meaningful role as part of a climate solution.”
He likened it to taking a painkiller for a cavity without a plan to see a dentist.
“So, if we don’t address the underlying cause of sea level rise, there is nothing geoengineering, that we can do that will stop sea level rise,” he said.
MacAyeal has heard criticism of the field, which he said is at a crossroads. He pointed out that the goal is, in no way, designed to provide an excuse for anyone to not regard the reduction of carbon dioxide emissions as the number one way in which humans can advance a better future.
“Even though, the idea that if we develop knowledge on glacial geoengineering, that’ll be a deterrence to further emission reduction. That is one of the main criticisms of all geoengineering,” said MacYeal.
“I don’t know how to answer that criticism other than … in my gut feeling, knowledge is better than ignorance. And, maybe if we fail to curb climate change, maybe we might have to resort to some of these things,” he said.
