Richard A Lovett
In a plan that sounds more like science fiction than something you’d expect in a major scientific journal, researchers from Germany are proposing that one solution for rising sea levels might be to create artificial blizzards in Antarctica.
The goal, say Johannes Feldmann and colleagues from the Potsdam Institute for Climate Impact Research, is to reduce the rate of ice flow from two major glaciers in West Antarctica – the Pine Island Glacier and the Thwaites Glacier.
Currently, Feldmann’s team writes in the online journal Science Advances, these glaciers are flowing ever more quickly into the Southern Ocean.
At the moment, they are contributing about half a millimetre per year to global sea level rise, but if they “collapse” and increase their flow dramatically, they could eventually cause as much as three metres of rise – enough to inundate large portions of such major coastal cities as New York, Calcutta, Shanghai and Tokyo.
To stop this, Feldmann and colleagues propose a massive geoengineering project in which vast quantities of seawater would be pumped onto the glacier’s slopes, thereby increasing their weight and slowing the glaciers’ advance toward the sea by; in essence, pinning them more firmly against the underlying bedrock.
The amount of snow needed to do this, however, would be truly gargantuan – tens of metres per year over an area half the size of Iceland, the study suggests. {%recommended 7367%}
But, it adds, that’s not impossible. Doing it would begin by pumping all of that water up from sea level to about 640 metres, the elevation where the extra mass of snow would do the most good.
That alone would require 145 gigawatts of energy – about the output of 12,000 high-end wind turbines. But the water would also have to be desalinated (to prevent its salt from melting the ice and undoing the entire project – another energy-intensive procedure.
And the process of spraying it into the air to fall back as snow – a technology commonly used by alpine ski areas in poor snow years – requires even more energy.
Other scientists are cautiously sceptical. Ken Caldeira, a climate scientist at the Carnegie Institution for Science’s Department of Global Ecology, in Stanford, California, notes that as massive as such a project’s proposed energy use sounds, it’s only a small fraction of humanity’s current energy-generating capability worldwide. So, he says, “[It’s] not completely crazy on the face of it.”
But, he adds, “I am not an expert in ice sheet modelling but I would ask about things like ice cliff instability”.
Ice cliff instability is a process under which glaciers that meet the sea in tall ice cliffs – as might be formed when the artificial-snow-thickened ice eventually reaches the ocean – break off more readily, forming more (and larger) icebergs to float away and subsequently melt.
Richard Alley, a glaciologist and climate researcher at Pennsylvania State University, agrees. “If cliffs form, taller ones might be even more unstable, depending on a lot of poorly known issues,” he says.
Furthermore, he says, ice loss from glaciers flowing into the sea can also be driven by ocean warming from below – a process that will continue as the planet warms.
That said, the new study isn’t so much a full-fledged geoengineering proposal as a demonstration of the magnitude of the problem that humanity is facing and the scale of the methods that may be needed to offset it.
Feldmann and colleagues in fact agree with Caldeira’s and Alley’s uncertainties, and add a few of their own.
Such a massive project, they say, would create a lot of underwater noise that would be harmful to marine mammals, and would otherwise disrupt ocean ecosystems by altering the flow of water near the pumping stations.
Nor would it do anything to reduce global warming from the buildup of carbon dioxide and other planet-warming gases.
What it is, they say, is “proof of concept.”
Alley adds, “I would view this as a first step, rather than a demonstration that it will work”.
