Could Freezing Arctic Sea Ice Combat Climate Change?
Rachel Feltman: For Scientific American’s Science Quickly, I’m Rachel Feltman.
You don’t have to pay much attention to the news to know that climate change is causing Arctic sea ice to melt—and to understand that this is a huge problem. Ice reflects sunlight, which helps keep cold places cold. Warmer weather means less ice, but less ice means more heat from the sun, which means it gets warmer, which means there’s less ice—and the sea level keeps rising and rising.
It would be great if we could cut this problem off at the source by dropping our greenhouse gas emissions, but we’re not exactly making great progress on that front. In the meantime what if we could just make more ice?
It might sound silly, but some folks in the polar geoengineering space are making a very serious attempt to do just that.
To get the inside scoop I’m handing the reins over to Pulitzer Center ocean reporting fellow Alec Luhn. He’s the author of a feature on the subject in Scientific American’s June issue, and today he’s going to take us along on a trip to the Arctic.
[CLIP: Snowmobile engine starting.]
Alec Luhn: I’m snowmobiling out onto the sea ice from the Inuit village of Cambridge Bay in Canada’s Arctic Archipelago. It’s –26 degrees Celsius. That’s –15 degrees in Fahrenheit. The blasting wind makes it feel far colder. My goggles are freezing over, and my thumb is getting numb on the throttle. But this is actually warm for Cambridge Bay in February. It’s been the warmest winter in 75 years, and the temperature at the North Pole even briefly went above freezing.
In front of me a local Inuit guide is towing a sled full of team members from the U.K. company Real Ice to a point about seven kilometers [roughly 4.3 miles] from town.
Scientists say as early as the 2030s the Arctic ice cap could start melting away completely in the summertime, raising temperatures around the globe. Real Ice hopes to stop that by artificially freezing more sea ice. It’s one of several geoengineering projects trying to save the world’s glaciers, ice sheets and sea ice.
Some scientists think it’s ridiculous or even dangerous, but Real Ice co-founder Cían Sherwin says we no longer have any option but to try.
Cían Sherwin: So right now we’re about to start drilling the—that 10-inch [25.4-centimeter] auger hole for the pump.
[CLIP: Cían Sherwin drills into the sea ice.]
Luhn: Cían was part of a student group at Bangor University in Wales that built a “reicing machine” after they saw a TV documentary about the melting Arctic. In 2022 he co-founded Real Ice to try it on a larger scale.
The ice outside Cambridge Bay is more than a meter [approximately 3.3 feet] thick. Cían drills a hole in it with a long battery-powered auger. If you’ve ever been ice fishing, you’ve seen this kind of tool. It looks kind of like a jackhammer, only with a giant rotating screw rather than a chisel at the end.
Inuit guide David Kavanna widens the edges of the hole with an ice saw, and the team puts a wooden box around it. Cían lowers an industrial pump with a long hose through the hole. He plugs a cable into a battery pack, and seawater starts pouring out of the hose, creating a brilliant blue pool on the sea ice.
Sherwin: Where that flow rate isn’t as strong, the ice—or the water acts almost like lava, becoming thicker in viscosity, and ice formation starts to begin almost instantly.
Luhn: Sea ice freezes from below, where there’s water that’s just under zero degrees C [32 degrees F]. But once the first layer of ice forms it partially insulates that water from the freezing air above, which can be as cold as –50 degrees C [–58 degrees F]. So the thicker the ice gets, the slower it grows. Real Ice is trying to bring the water up to the cold air by pumping it on top of the sea ice.
After about three hours the team comes back to take the pump out. The pool of water has congealed into an electric blue slush, like a gas station Slurpee.
Sherwin: So by the time we return here now, tomorrow morning, this will already be frozen.
Luhn (tape): New sea ice?
Sherwin: New sea ice—or a new layer on top of the sea ice.
Luhn: Releasing small particles to block sunlight is probably the most common geoengineering idea. It’s also highly controversial because it could affect weather, like rainfall. Mexico banned solar geoengineering after an American firm released balloons full of sulfur dioxide there. A city in California recently halted an experiment spraying sea-salt particles into the air.
In May the U.K. allocated about $75 million to geoengineering research, becoming one of the first countries to fund outdoor experiments in this field. One experiment will launch balloons to test mineral dust that could someday be released into the atmosphere to block sunlight. Another two will develop nozzles to spray sea-salt particles, including potentially over Australia’s Great Barrier Reef.
But the largest grant in the British program, about $13 million, went to a research group that includes Real Ice. It also includes the Dutch company Arctic Reflections, which has been testing giant pumping platforms to thicken sea ice in Svalbard [Norway] and Newfoundland, Canada.
Polar geoengineering trials have been moving forward in other places, too. A U.S. nonprofit has been scattering tiny white clay granules to reflect more sunlight away from glaciers in Iceland and the Himalayas. And a Scandinavian project has been testing materials for huge underwater curtains to try and stop warm water from reaching the underside of Antarctic glaciers and melting and collapsing them.
If it works, polar geoengineering like sea-ice thickening could affect the entire Earth. Arctic sea ice is like a big mirror, reflecting up to 90 percent of the sun’s radiation back into space when it’s covered in snow. But ocean water absorbs 90 percent of sunlight. The more ice melts, the more ocean water warms. That heats up the planet—and melts even more ice.
The thick sea ice that lasts year round has shrunk about 40 percent in the last four decades. If it starts melting away completely in the summertime, global temperatures could rise an extra 0.19 degrees C [roughly 0.34 degrees F] by 2050.
Last winter real ice thickened about 250,000 square meters [almost 2.7 million square feet] of sea ice. In the winter of 2027–28 the company plans to thicken 100 square kilometers [about 38.6 square miles] as a demonstration. If that works, the team hopes it could scale up to eventually keep Arctic sea ice from disappearing in the summer.
Sherwin: Targeting an area roughly a million square kilometers [about 386,100 square miles]across the entire Arctic region could be enough to help prevent the loss of sea ice.
Luhn: On the one hand that’s small: it’s one fifth of how much ice is currently left in the summertime. On the other hand it’s enormous: the size of Texas and New Mexico combined. Real Ice says it could be possible. All they’d need is half a million underwater drones... [full transcript]
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