Antarctica’s ‘Doomsday’ glacier is melting faster than expected, intensifying calls for geoengineering

New research on the Thwaites Glacier, also called the Doomsday Glacier, has sparked talk of geoengineering as a solution to climate change.

One study published in May, led by scientists at the University of California, Irvine and the University of Waterloo, found that warming tidal currents are accelerating the melting of the Thwaites and leading to faster retreat than models predicted. another study published in August and carried out by researchers from Dartmouth College and the 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 unknown, some scientists and engineers are turning to controversial ideas about how to change the environment to slow the melting of glaciers.

Understanding the accelerated melting of warm tidal currents

Thwaites Glacier is one of a chain of glaciers located along the seaward edge of the West Antarctic Ice Sheet (WAIS), a massive ice bowl nearly three times the size of Texas located in a basin below sea level in West Antarctica. The only strongholds that prevent the ocean from filling the basin and melting or dislodging the ice are glaciers.

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

The Thwaites quickly retreat due to climate changeand already amounts to 4% sea level rise on Earth, losing 50 billion tons of ice every year. Due to the catastrophic sea level rise that will occur, the Thwaites breach and subsequent displacement of the WAIS is what is known as turning point in climate science.

A tipping point is when a critical threshold (in this case atmospheric and ocean warming) is crossed, leading to major, accelerating, and irreversible changes in the climate system. The melting of the Thwaites Glacier will cause the collapse of the WAIS, which in turn will lead to irreversible sea level rise that could put millions of people at risk and accelerate the warming of other ice sheets.

PNAS The study, led by researchers from the University of California, Irvine and the University of Waterloo, used high-resolution satellite imagery and hydrological data to identify areas where warm tidal currents flowed under the ice and caused faster melting. Understanding melt rates is critical to predicting sea level rise, according to Christina Dow.

Dow, assistant professor of glaciology at the University of Waterloo and co-author of the study, said in his report. interview With Scientific American“We were hoping it would take a hundred, five hundred years to lose this ice. The big concern now is that this will happen much faster.”

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

The MICI hypothesis suggests that tall ice cliffs formed by retreating glaciers are unstable and more easily eroded, but this study found that thinning the Thwaites River may actually reduce calving rates and stabilize ice cliffs. emphasizing the need for better models when making forecasts about WAIS.

Debate over geoengineering as a solution

Faced with uncertainty and the possibility of rapid and extreme sea ​​level rise If Thwaites melts faster than expected, some scientists will turn to glacial geoengineering – the process of using technology and infrastructure to slow or stop the retreat of glaciers even as global temperatures rise – as a potential solution.

A group of glaciologists affiliated with the University of Chicago Climate Systems Initiative published report in July this year called for more research into glacial geoengineering in response to threats posed by rapidly retreating glaciers.

John Moore, a professor at the University of Lapland’s Arctic Center and co-author of the report, explained to UChicago News the need to start this work now, saying, “It will take us 15 to 30 years to understand enough to recommend or rule out any (glacial geoengineering) interventions,” i.e. their preparation must begin immediately.

Some ideas for protecting Thwaites and other sea-ending glaciers like it are considered radical, including creating giant underwater curtains this would at least partially prevent warm tidal currents from reaching the glacier. Curtains could be made from fabric or even bubbles by placing a pipe with holes drilled in it and air pumped through it between the Thwaites and the warm water.

According to Gernot Wagner, a climate economist at the Columbia Climate School, such glacial geoengineering interventions could be extremely beneficial if implemented correctly. In an interview with GlacierHub, Wagner said: “For some polar tipping points, such as Arctic sea ice and WAIS, glacial geoengineering seems to be the only way for us to more or less ensure that we can deal with these tipping points.”

However, many of these ideas have faced opposition from glaciologists and climate scientists who argue they will be difficult or impossible to achieve and distract attention from the more necessary conversation about reducing carbon emissions. These scientists argue that by relying too much on strategies like geoengineering, we may fail to take action to curb emissions.

Wagner takes a subtle approach. His initial reaction to the idea of ​​installing curtains was: “It seems crazy. Geoengineering options like these curtains could distract attention from the need to reduce emissions.” On the other hand, he says, “you can use this as a nudge to say, ‘Wait, if serious people are talking about using curtains as a solution, maybe we should take this more seriously and cut emissions significantly.’ “

As we approach climate tipping points such as the melting of the Thwaites Glacier, many believe geoengineering can be a powerful tool if 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 is not a solution to climate change—at best, it is a painkiller. It allows us to get out of bed and do what needs to be done. to eliminate the underlying disease while simultaneously relieving the most severe pain.

“(But) geoengineering doesn’t solve anything, so we need to use the time it gives us to solve emissions problems.”

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