How Antarctica ‘Doomsday Glacier’ Thwaites could COLLAPSE and send sea levels soaring

EARTH'S most dangerous chunk of ice is probably the Thwaites Glacier in Antarctica – so at risk it's called the "Doomsday Glacier".

But is it really at risk of disappearing, and how much damage would it cause? Here's what you need to know.

Antarctica's ice – what's going on?

When we think of Antarctic ice, it's tempting to think of huge bergs floating through the sea.

But that ice is already in the water, and therefore can't increase sea levels.

The real threat is all of the Antarctic ice locked on land, which can melt and flow into the ocean.

Around 90% of the world's freshwater is in Antarctica, so the potential for melt is huge.

Antarctica is split into two main ice sheets: west and east.

The eastern sheet is actually reasonably safe in the short-term. It's mostly above sea level, and the ice is very thick.

But the west sheet is a real worry.

For a start, it's much smaller and – like ice cubes in your drink – melt faster the smaller they are.

It's also almost entirely below sea level. In fact, it would be largely underwater if it wasn't for enormous barriers of glacial ice keeping the sea at bay.

So the western sheet is at risk of flooding (and therefore melting) if the barrier of ice is damaged significantly.

Thwaites Glacier – what is it and why should we care?

The Thwaites Glacier is...a glacier. A massive one that poses such risk it's been branded the 'Doomsday Glacier".

Glaciers are huge sheets of ice moving very slowly, and contain vast amounts of water.

It's a little smaller than Britain, so it's absolutely massive.

And it's melting very quickly, which is a huge concern to scientists.

To make matters worse, Nasa uncovered an enormous cavity below Thwaites just last year.

This enormous hole is around 300 metres tall and roughly two-thirds the size of Manhattan.

This adds a real risk of collapse to the already fast-melting glacier.

If Thwaites disappears, what happens?

If Thwaites melted, estimates suggest sea levels globally would rise around 0.5 metres on average.

That would be devastating for low-lying coastal communities. But it's not the worst bit.

Think of Thwaites a bit like a keystone in an arch, holding everything together.

Thwaites sits on a central edge of Antarctica's western sheet, and can be traced far inland.

If Thwaites disappears, it risks destabilising huge parts of the west sheet.

When it disappears, warm water can flood much further inland. A higher percentage of the sheet is then in contact with water.

And without the physical support of the massive glacier, chunks can start to break off more easily.

Loss of ice means faster melting generally, too. There's less ice to cool the remaining ice down.

Scientists think that the western ice sheet holds an additional 3 metres of sea level rise.

So if the entire sheet were to melt, it would pose huge problems for coastal areas around the world.

Is Thwaites likely to disappear?

Yes, sadly.

It's melting quickly, and could very well disappear within a few centuries.

Thwaites also slopes downwards towards the ocean, which means the higher ice at the back is constantly trying to force itself into the sea.

What we don't know is how much of an impact that will have on the ice sheet surrounding Thwaites – because it's very difficult to model.

Scientists are investigating how to slow or stop the glacier melting, but there's no concrete answer just yet.

What we do know is that as seas warm and rise, Thwaites will be under increasing threat.

And its structure seems to be too weak to sustain itself forever.

If sea levels rise, what would happen?

Sea levels rising creates an obvious risk to any low-lying populated regions near the coast.

Many towns, cities and villages are built near oceans, because the sea is a great resource and makes trading easier.

Sadly this means low-lying coasts are often hugely populated, and many places people call home today could end up underwater in the future.

This isn't a new phenomenon: a huge area around Britain and Europe called Doggerland was once above sea level, but now rests at the bottom of the ocean.

It's also worth remembering that rising sea levels mean tsunamis and storm surges can reach much farther in land.

And the threat of flooding quickly increases as sea levels rise.

And let's not forget: rising sea levels are also a self-fulfilling property.

The more sea levels rise, the more damage they can do to Antarctica's ice sheets.

And the more the ice sheets melt, the more sea levels rise.

This cyclical process concerns scientists, who fear a "runaway effect" where sea levels begin to rise very quickly.

Is it all doom and gloom?

Yes and no.

Rising sea levels pose real risks to many people around the world.

We shouldn't underestimate that, and coastal areas need to work on flood defences.

Governments also need to work on reducing their contribution to climate change to avoid accelerating any damage.

But not all of Antractica's ice is doomed – and scientists hope much of it can be preserved.

The Thwaites Glacier might one day disappear, but it doesn't spell the end for humanity.

In other news, the first full map of the hidden continent below Antarctica has been revealed.

Antarctica is being melted from below by warm underground rivers, panicked scientists have warned.

And, experts think melting Antarctic ice could cause areas of the ocean to turn a "deep green" colour by 2100.

Are you worried about climate change? Let us know in the comments!

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