‘Doomsday’ Antarctic glacier melting faster than expected, fueling calls for geoengineering

New studies about the Thwaites Glacier, also called the “Doomsday Glacier,” have sparked a conversation about geoengineering as a climate change solution.

One study published in May and led by University of California Irvine and University of Waterloo scientists found that warming tidal currents are accelerating the Thwaites’ melting and leading to quicker retreat than models have predicted, while another study published in August and led by researchers at Dartmouth College and University of Edinburgh found that the Thwaites may be less vulnerable to instability and collapse than previously thought.

With the fate of the Thwaites still uncertain, some scientists and engineers are turning to controversial ideas on how to alter the environment to slow glacier melt.

Understanding accelerated melt from warm tidal currents

The Thwaites Glacier is one of a line of glaciers sitting along the marine-facing rim of the West Antarctic Ice Sheet (WAIS)—a massive bowl of ice nearly three times the size of Texas sitting in a basin below sea level in Western Antarctica. The only bulwarks that prevent the ocean from filling the basin and melting or dislodging the ice are the glaciers.

This situation has led scientists and the media to term the Thwaites—a glacier larger than the entire state of Florida—the “Doomsday Glacier” because its breach would allow warmer ocean waters to melt the WAIS and raise sea levels by nearly 11 feet. This would put many large coastal cities and small island nations at extreme risk.

The Thwaites is retreating rapidly due to climate change, and already accounts for 4% of sea level rise on Earth, losing 50 billion tons of ice each year. Due to the catastrophic sea level rise that would occur, the breaching of the Thwaites and subsequent dislodgement of the WAIS are what’s known as a tipping point in climate science.

A tipping point is when crossing a critical threshold—in this case, atmospheric and oceanic warming—leads to large, accelerating, and irreversible changes in the climate system. The melting of the Thwaites Glacier would lead to the collapse of the WAIS which would in turn cause irreversible sea level rise that could endanger millions of people and accelerate warming of other ice.

The PNAS study led by UC Irvine and University of Waterloo researchers used high-resolution satellite images and hydrological data to identify areas where warm tidal currents were flowing under the ice and causing faster melt. Understanding the melt rate is critical for predicting sea level rise according to Christine Dow.

Dow, an associate professor of glaciology at the University of Waterloo and a co-author of the study, said in an interview with Scientific American, “We were hoping it would take a hundred, 500 years to lose that ice. A big concern right now is if it happens much faster than that.”

However, there is some hope for the WAIS. The study by Dartmouth College and University of Edinburgh researchers found that the Thwaites is not as susceptible to a process called marine ice cliff instability (MICI) as previously thought.

The MICI hypothesis suggests that tall ice cliffs formed by retreating glaciers are unstable and collapse more easily, but this study showed that thinning of the Thwaites could actually reduce the calving rate and stabilize ice cliffs, highlighting the need for better models when making predictions about the WAIS.

Debate over geoengineering as a solution

Faced with uncertainty and the potential of rapid and extreme sea level rise if the Thwaites melts faster than expected, some scientists are turning to glacial geoengineering—the process of using technology and infrastructure to slow or stop glacier retreat even as global temperatures increase—as a potential solution.

A group of glaciologists affiliated with the Climate Systems Engineering Initiative at the University of Chicago released a report in July of this year calling for more research into glacier geoengineering in response to the threats posed by rapidly retreating glaciers.

John Moore, a professor with the Arctic Center at the University of Lapland and co-author of the report, explained the necessity of starting this work now to UChicago News, saying, “it will take 15 to 30 years for us to understand enough to recommend or rule out any [glacier geoengineering] interventions,” meaning they must start immediately to be prepared.

Some of the ideas for protecting the Thwaites and other marine-terminating glaciers like it are considered radical, including creating giant submarine curtains that would at least partially prevent warm tidal currents from reaching the glacier ice. The curtains could be made of fabric or even bubbles if a pipe with holes drilled into it and air pumped through it could be placed between the Thwaites and the warm water.

Glacial geoengineering interventions like these could be extremely useful if implemented correctly, according to Gernot Wagner, a climate economist in the Columbia Climate School. In an interview with GlacierHub, Wagner said, “for some polar tipping points like Arctic sea ice and the WAIS, glacial geoengineering seems to be the only way for us to more or less guarantee that we can address these tipping points.”

However, many of these ideas have faced opposition from glaciologists and climate scientists who claim that they would be difficult or impossible to achieve and draw focus away from the more necessary conversation of reducing carbon emissions. By relying too much on strategies like geoengineering, these scientists argue we may fail to act to curb emissions.

Wagner takes a nuanced approach. His initial reaction to the idea of installing curtains was “that it seems crazy. Geoengineering options like these curtains could detract from the need to cut emissions.” On the flipside, he said, “you can use it as a push to say, ‘wait, if serious people are talking about [using curtains] as a solution, maybe we should be taking it more seriously and cutting emissions much more.'”

As we creep closer to climate tipping points like the melting of the Thwaites Glacier, many believe geoengineering has the potential to be a powerful tool so long as it is not treated as a silver bullet. As Wagner stated, “When we talk about glacial geoengineering, we need to tell the truth, which is that it’s not a solution to climate change—at best, it’s a painkiller. It allows us to get out of bed and do what is necessary to address the underlying illness while taking the edge off the worst of the pain.

“[But] geoengineering doesn’t solve anything, so we need to use the time it gives us to address emissions.”

This story is republished courtesy of Earth Institute, Columbia University http://blogs.ei.columbia.edu.