What is the Doomsday Glacier and Why Does it Matter?

The Doomsday Glacier (aka. Thwaites Glacier) has garnered a lot of media attention in recent years due to the threat it poses to rising global sea levels. Scientific research has revealed that the glacier is one of the fastest receding glaciers and also has one of the least stable ice shelves in all of West Antarctica. Not only this, but the collapse of the Doomsday Glacier risks creating a knock on effect and brings into question the stability of surrounding glaciers too. 

👉 In this article we’ll explore what the Doomsday Glacier actually is, why it’s got scientists so worried, and what we can do to prevent its collapse.

Thwaites Glacier, aka. the Doomsday Glacier is huge in size, measuring in at around 120 km wide and covering an area of 192,000 square kilometers. To put its size into perspective, the glacier is larger than England, Wales and Northern Ireland put together - or larger than the state of Florida for our American readers! And like many glaciers across the world, the Doomsday Glacier is on the retreat, losing around 50 billion tons more ice than is replaced by fresh snowfall every year. 

Even more worrying is the fact that the amount of ice loss suffered by the glacier has doubled over the last thirty years alone which means that the rate of ice loss is increasing.

As with many glaciers, melted water from the Doomsday Glacier runs off directly from the glacier, into the ocean. This means that the more the glacier melts, the bigger the threat to rising sea levels it represents. 

As it currently stands, the global sea level rises by about 3 millimeters every year, and experts believe that the Doomsday Glacier supplies as much as 4% of this incoming water. If the Doomsday Glacier were to suddenly collapse, global sea levels would rise by as much as 65cm - which would result in disastrous consequences. 

Not only would the melting ice result in a significant sea level rise across the globe, but the collapse of the Doomsday Glacier also has the potential to set off a chain reaction, resulting in the breakdown of surrounding glaciers too. If the Thwaites Glacier’s neighbors were to also collapse, sea levels could rise by as much as an additional 3 meters. 

Worryingly, the Doomsday Glacier is undergoing the largest changes of any ice-ocean system in Antarctica: it’s one of the fastest receding glaciers and also has one of the least stable ice shelves. This is why the glacier has attracted so much media attention in recent years. 

The Doomsday Glacier is partly supported by an ice shelf (ie. the Thwaites ice Shelf) that extends out into the ocean. This ice shelf acts as a sort of plug, supporting the land-bound glacier and protecting it from the warmer ocean waters. However, this important ice shelf is under threat from the rising temperatures of our ocean waters and scientists are concerned that the ice shelf could collapse within the next decade, causing the glaciers' contribution to global sea level rises to increase from 4% to 5% in the short term, and accelerating even further over the next few centuries.

Scientists have been studying the Doomsday Glacier for several decades and have measured an increase in both the glacier’s flow, and a retreat of its grounding line. So what exactly does this mean? 

Glacial flow refers to the movement of the glacier. This movement is caused by gravity and means that glaciers will always flow downstream - in the case of the Doomsday Glacier, it’s an outlet glacier, which is to say that it’s flowing towards the ocean. 

This movement is what causes the ice shelf to form - in the case of the Doomsday Glacier this dazzling-white ice shelf is vast, stretching out for 120km, standing 40 meters above sea level, and reaching a depth of 200 meters below the ocean’s surface. 

The problem with an increasing glacial flow is that it causes the ice shelf to break up more quickly than new ice can be created, thereby destabilizing the ice shelf. This is highly problematic since the ice shelf provides stability to the glacier and is preventing a rapid acceleration in its collapse. 

The retreat of the Doomsday Glacier’s grounding line is another observation of the glacier’s increasing instability. The grounding line is a term that describes the boundary between the floating ice and the ice that sits on top of actual land. A retreating grounding line isn’t good news. As the grounding line retreats back inland, a cavity is created underneath the now floating ice sheet; the larger this is the more unstable the ice sheet becomes and the more prone to collapse and breaking off it is. 

The Doomsday Glacier’s receding grounding line has led to the creation of a gigantic cavern at the bottom of the Doomsday Glacier. The retreat of this line allowed for warmer ocean water to find new gaps between the bedrock and the ice above it, which meant that the water was able to flow in, melting the glacier from below. 

In 2021, a NASA led study discovered the scale of the cavity. Standing at nearly 300 meters in height and two thirds the size of the area of Manhattan, the cavity is thought to have once contained around 14 billion tons of ice. 

What was most shocking about the discovery however, was the speed at which the cavity was formed. It only took 3 years for the ice to melt and for the cavernous space to take its place. This heightens the risk of the glacier becoming dislodged from the rock bed, below which helps to keep it in place and to maintain its stability. 

Recent studies have shown that the threat presented to the Doomsday Glacier is a lot more nuanced than originally thought and it’s melting in a way that has surprised scientists. Research has revealed that even though the glacier is receding, the rate of ice melt at its base is less than expected, which is certainly good news. However, there is also cause for concern. 

The underwater landscape of the glacier is made up of staircase-like structures called terraces, alongside other cracks and crevasses. The rate of melting was found to be particularly high in these areas, which is worrying since it allows the warmer ocean water to infiltrate the glacier and to advance the rate of melting, creating instability as it goes. Scientists have even warned that these features could trigger the collapse of the ice shelf within the next ten years.

The Doomsday Glacier, like many glaciers across the world, is experiencing an increased rate of melting and retreat on account of human activity. 

The industrial revolution marked the beginning of our unsustainable use and reliance on fossil fuels such as coal, petroleum and natural gas. This resulted in the expulsion of carbon dioxide and other greenhouse gases into the Earth’s atmosphere, causing global temperatures to rise and warming our ocean waters. 

The effect of global warming is even more pronounced at the Earth’s polar regions, which means that glaciers such as the Doomsday Glacier are experiencing rapid rates of melting and retreat.

We’ve already talked about rising sea levels as a result of glacial collapse, but what exactly would this mean for mankind? 

The melting of glaciers such as the Doomsday Glacier in remote regions like the Antarctic have global effects. With the excess water entering our oceans we can expect sea levels to rise, which threatens coastal communities, forcing migration and putting livelihoods at risk. 

But these are not the only effects. The glacial melt also has the potential to alter the circulation of our oceans and affect weather patterns across the globe. The melting of glaciers in the Antarctic region in particular is changing the circulation of deep ocean water, something that is crucial for the health of our oceans and that also plays an important part in absorbing and storing excess carbon dioxide from the atmosphere.

❗️ The Doomsday Glacier’s called this for a reason, and scientists are highly concerned by the glacier’s rapid rate of retreat. Their research has revealed that the Thwaites ice shelf is at risk of collapse as soon as the next decade, which will ultimately accelerate the rate at which the glacier itself declines. 

However, even if the ice shelf collapses, the effects will be progressive and it will take several centuries for the glacier to melt. So what can we do in the meantime to prevent the melting of glaciers? 

The most important thing that we can do to try and slow down the rate of glacier melt is to eliminate the emission of greenhouse gasses. As long as we’re releasing these gasses into the air, global temperatures will continue to rise, which means that glaciers will continue to suffer from accelerated melting. This is why it’s so important that we take steps to decarbonise our societies and to reduce our dependence on fossil fuels. 

❗️Even if we manage to reach net zero emissions, a lot of damage has already been done, and the Earth’s glaciers will continue to melt for decades to come. This is why scientific research into the melting of glaciers such as the Doomsday Glacier is so important - it allows scientists to create models that predict the impacts of the melting ice, which will help us to better prepare for and adapt to the effects of climate change.

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