Satellite images reveal huge CRACKS in Greenland glacier | Daily Mail Online

Satellite images reveal huge CRACKS in Greenland glacier, sparking fears massive chunk will break off and cause more ice to spill into the sea

By Cheyenne Macdonald For Dailymail.com

Published: 19:06 EST, 7 February 2019 | Updated: 19:07 EST, 7 February 2019

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Scientists have spotted a massive crack running through one of the most prominent glaciers in northwest Greenland.

Ice flow at the Petermann Glacier has been speeding up over the past few years, and satellite images now suggest a new iceberg could break free sometime in the near future.

Petermann is one of just three glaciers in Greenland that has an ice tongue – a 43-mile floating expanse that stretches into the Petermann Fjord.

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According to a new study led by AWI, the recent acceleration was spurred by the loss of a large iceberg back in August 2012 (shown on left). According to the models, a similar phenomenon could occur if another piece breaks off. Recent satellite images (right) show massive cracks that could signal a calving event

WHAT IS A GLACIER CALVING EVENT? 

Glacier calving is a natural occurrence caused by the forward motion of a glacier making its end unstable.

During a calving event, part of the end of a glacier drops off, often forming an iceberg.

Calving of glaciers is often accompanied by a loud cracking or booming sound before blocks of ice up to 60 metres (200 ft) high break loose and crash into the water.

The entry of this ice into the water can cause large and hazardous waves.

‘The satellite data shows that Petermann Glacier had a flow speed of roughly 1135 meters per year in the winter of 2016,’ said glaciologist Niklas Neckel, from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).

‘That equates to an acceleration of about 10 percent in comparison to the winter of 2011, and we asked ourselves what was responsible for the increased speed.’

According to a new study led by AWI, the recent acceleration was spurred by the loss of a large iceberg back in August 2012.

And, according to the models, a similar phenomenon could occur if another piece breaks off.

‘On their way to the sea, the glacier’s ice masses rub along the rock walls that enclose the fjord to the left and the right,’ said lead author, AWI ice modeller Martin Rückamp.

‘If a major iceberg breaks away from the end of the glacier’s tongue, it will reduce the tongue’s overall length, and with it, the route along which the ice masses scrape against the stone.

‘This in turn limits the walls’ braking effect, so that the glacier begins flowing faster.’

Ice flow at the Petermann Glacier has been speeding up over the past few years, and satellite images now suggest a new iceberg could break free sometime in the near future. Peterman is one of just three glaciers in Greenland that has an ice tongue – a 43-mile floating expanse that stretches into the Petermann Fjord

As of now, scientists say it’s too early to know when an iceberg will break free from the glacier. When it does happen, though, it won’t be an isolated event.

‘We can’t predict when Petermann Glacier will calve again, or whether a calving event would actually calve along the cracks we identified in the ice tongue,’ Rückamp said.

‘But we can safely assume that, if it does come to a new calving event, the tongue will retreat considerably, and the rock’s stabilizing effect will further decline.’

Northern Greenland has been relatively stable compared to its southern reaches, where glaciers have seen far more acceleration.

Scientists have spotted a massive crack running through one of the most prominent glaciers in northwest Greenland. As of now, scientists say it’s too early to know when an iceberg will break free from the glacier. When it does happen, though, it won’t be an isolated event

‘If a major iceberg breaks away from the end of the glacier’s tongue, it will reduce the tongue’s overall length, and with it, the route along which the ice masses scrape against the stone. ‘This in turn limits the walls’ braking effect, so that the glacier begins flowing faster,' the researchers warn. The glacier is shown above

Now, however, the researchers say this may be changing.

‘We now know that the loss of icebergs increases the glacier’s flow rate,’ Neckel said.

‘In addition, we’ve observed that calving events on Petermann Glacier are happening more frequently.

‘But the question of whether these changes are due to the warming atmosphere over Greenland, or to warmer seawater, isn’t an aspect that we could investigate using the satellite data.’

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https://www.dailymail.co.uk/sciencetech/article-6680501/Satellite-images-reveal-huge-CRACKS-Greenland-glacier.html