In the minutes it takes to read this article, nearly 12 million tons of ice will have melted away from Greenland’s ice sheet alone.
In August, scientists made a startling discovery: Even if global warming serendipitously ceased to exist today, the melting process already underway is now irreversible. Sea ice in the polar regions is melting so fast that the Arctic may be ice-free by the 2030s, and Antarctica's glaciers are unstable and at risk of collapsing.
Ice loss puts the planet at risk for a cascade of environmental issues. The thinning and loss of sea ice, for example, accelerates global warming. Glacial ice loss, on the other hand, acidifies the ocean, modifies weather patterns, and contributes to global rising sea levels, The latter leaves hundreds of millions vulnerable: coastal flooding, erosion, and compromising drinking water supplies, to name a few.
“The melting we’ve been experiencing is not going to get better—it’s only going to get worse,” said Catherine Walker, a glaciologist at Woods Hole Oceanographic Institution in Massachusetts.
While human-caused global warming has taken the world’s ice past the tipping point, some say the only solution must also come from humans in the form of massive intervention to reverse the warming processes already underway. Enter: Geoengineering.
Geoengineering is an umbrella term for the controversial idea of intervening in the Earth’s natural systems using emerging technologies to counteract the climate crisis. The solutions vary tremendously in viability, side effects, infrastructure needs, and timeline. Where they do intersect is scale: the proposed solutions are as big and potentially disruptive as the processes they’re intended to halt.
“We’re past the point of no return if we don’t do negative emissions or geoengineering,” said Peter Irvine, climate change lecturer at University College London. “But with these, we could stabilize things.”
Glaciologists, however, have many concerns about the possible unintended side effects of these solutions. Will geoengineering do more environmental harm than good?
“Geoengineering gives us a modicum of hope that we can find a technological fix, but I think we’re much more likely to end up with massive unintended consequences from any experiment we would try to do,” said Dr. Michele Koppes, a glaciologist at the University of British Columbia.
“We know how to change things. We’re causing it in the first place”
According to Professor Helen Amanda Fricker, a glaciologist at Scripps Polar Center at Scripps Institution of Oceanography, Earth’s systems are complex and there is so much unknown about polar regions that it is impossible to fully assess the environmental impacts of any geoengineering solution.
“Why wouldn’t we just fix the root cause?” asks Fricker. “We know how to change things. We’re causing it in the first place.”
Intertwined with engineering feasibility is the issue of scale. Antarctica, for example, is roughly the size of Mexico and the U.S. combined. Rolling out a solution on the glacial body would be a massive undertaking. “My gut reaction is we can’t even fathom how we would make a dent in these changes with any kind of geoengineering solution,” said Koppes.
For geoengineers, however, too much is at stake to not consider alternate solutions.
“To the best of our knowledge, the ice sheets are at severe danger,” said John Moore, a geoengineer and climate scientist at China's Beijing Normal University. “You have to put it in perspective: There are enormously bad things that will happen if we carry on just emitting greenhouse gases.”
What exactly would geoengineering solutions look like? Here are four leading concepts relating to melting polar ice.
Stratospheric Aerosol Injection
Proposal: Atmospheric aerosols are found naturally in the air and keep the Earth cool by reflecting sunlight back into space. Stratospheric aerosol injection proposes scattering aerosols into the upper atmosphere to keep temperatures low. This would, in turn, reduce surface water temperatures that are melting ice. The inspiration comes from the aftermath of volcanic eruptions, which have shown how an increase in aerosols can cool the planet.
Cost: at least $2.25 billion per year
Can it work? Moore and his peers have modeled this technology using Greenland’s ice sheet. While it can reduce surface temperature, the impact on ice sheets is limited since it doesn’t tackle ice melt caused by the warming ocean. In Greenland, where half the melt is due to surface temperatures, aerosol injection is promising. But for Antarctica, which is the bigger threat, it’s predicted to be less effective since the melt has more to do with the overall ocean temperature.
What’s the downside? Even if you limit aerosol injections to Greenland, the released particulate could spread around the world. Alan Robock, a climatologist at Rutgers University focusing on geoengineering, warns this technology has a plethora of possible biological impacts: drought in Africa and Asia, ozone depletion, continued ocean acidification, and even increased acid rain and snow. "Research is needed to evaluate the potential benefits and risks so that society can make an informed decision in the future about whether or not to deploy stratospheric injections,” said Robock.
Refreeze Sea Ice
Proposal: Sea ice is thinning and scientists at Arizona State University are proposing a solution to artificially thicken it. The idea is to use a wind-powered pump to take deep seawater from the ocean in the winter and place it on the ice’s surface. The water would refreeze in the cold winter temperatures, resulting in thicker ice that would be less vulnerable to thinning during the summer.
Cost: $50 billion per year to cover 10 percent of the Arctic
Can it work? It doesn’t look promising. In 2019, researchers tested the concept using a climate model and found it wouldn't make a dent in the big picture. Lorenzo Zampieri, lead author of the study and Ph.D. candidate at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, said that while they found pumping deep sea water onto the surface of ice sheets “could potentially delay the Arctic sea ice decline by some decades, this would not help in the fight against global warming and polar amplification.”
What’s the downside? Since deep seawater has more salt, Zampieri said the geoengineered sea ice cover would be saltier and it is unknown how the modified surface would impact the sea ice ecosystem. Plus, the massive pumps and equipment themselves could pollute the Arctic environment.
Reflecting Sunlight With Silica Beads
Proposal: When it comes to sea ice, age matters; old sea ice is thicker, more reflective and thus more effective at reflecting back sunlight. But ancient sea ice has declined by 95 percent, leaving young, thin sea ice on the surface of the ocean. Nonprofit Arctic Ice Project (formerly Ice911) is using hollow air-filled glass silica beads, which look like fine white beach sand, to increase the reflectivity of sea ice. The beads stick to ice and water to create a thin reflective layer on Arctic ice.
Cost: 100,000 km² of strategic targeted deployment would be roughly $1-5 billion per year
Can it work? The technology has been tested on contained pools of seawater in Utqiaġvik, Alaska, located north of the Arctic Circle. The scientists' preliminary findings are that silica bead-treated ice has higher reflectivity and thickness than untreated ice. The researchers propose strategically placing the beads for maximum impact using climate modeling.
What’s the downside? The silica beads would break down in the ocean—the sea naturally has 2.8 million billion tons of silica—raising questions about environmental impact. Leslie Field, Arctic Ice Project founder and CTO, said the next step is to collaborate on an ecotoxicology study to confirm her team’s findings that the beads are harmless to the local ecosystem. “My mantra here is first do no harm,” said Field.
An Underwater Seabed Curtain
Proposal: A team of international scientists suggests creating an underwater seabed curtain to block the warm water that is eroding the base of ice sheets. Inspired by kelp beds found in nature, the curtains—made of Teflon-coated glass fiber cloth, reinforced with hollow fiberglass pipes—would be anchored to the seabed. The concept evolved from a 2018 idea to prop melting glaciers using underwater sills.
Cost: A curtain outside Antarctica’s Thwaites Glacier alone would cost $20 billion.
Can it work? Bowie Keefer, adjunct at the University of British Columbia and mastermind behind the sea curtain idea, said the idea currently looks effective and feasible. That said, the idea has only undergone very preliminary modeling. Keefer isn’t recommending this should be built at this point, but that it should be further explored.
What’s the downside? Cost and engineering in harsh environments. Keefer admits the landscape and cold temperatures would make building a sea curtain very difficult. But he still says it’s vital to assess it as a potential intervention to halt the underwater erosion of polar ice.