Greenland’s ice shelves have shrunk by more than a THIRD since 1978

  •  Of the eight ice shelves in North Greenland, three have collapsed completely
  •  Ice shelves hold back glaciers from the sea and prevent sea levels from rising 



Greenland’s ice shelves have lost more than a third of their volume since 1978, researchers have warned. 

Warm ocean waters have accelerated the disintegration of the vital ice shelves, melting them from beneath and increasing their risk of collapse. 

Of the eight ice shelves which support North Greenland’s vast glaciers, three have already collapsed completely, while the remaining five have rapidly retreated.

As the ocean continues to warm, scientists say the ice shelves will continue to retreat – with severe consequences for global sea levels.

If these disappear entirely, these ice shelves could release enough water to raise global sea levels by 6.8ft (2.1m), according to experts from the French National Centre for Scientific Research (CNRS). 

Scientists warn that Greenland’s eight floating ice shelves have shrunk by over 35 per cent since 1978 with three ice shelves collapsing completely
Satellite images show Ostenfeld ice shelf as it completely collapsed between 2003 and 2010

READ MORE: Humans have ‘lost control’ of the West Antarctic Ice Sheet melting

Greenland’s ice shelves were previously believed to be stable, unlike the more sensitive regions of the Polar Ice Cap.

However, scientists used field observations, aerial photography, satellite data, and regional climate models to show that the ice shelves have undergone a rapidly accelerating collapse. 

Since the 2000s, the floating ice shelves of Zachariæ Isstrøm, Ostenfeld and Hagen Brae glaciers have completely collapsed.

In 2003, 80 per cent of the Ostenfeld ice shelf collapsed into the sea, losing 6.5 cubic miles (27 cubic km) of ice.

Likewise, Hagen Bræ collapsed between 2001 and 2005, leaving a little more than a tenth of its original mass behind. 

Greenland’s vast glaciers, highlighted here in green, meet the sea by passing through a number of fjords where the ice shelves act like frozen dams
Hagen Bræ ice shelf went from being relatively stable in the 1980s to totally collapsing, after beginning to lose mass in the 2000s

The Greenland Ice Sheet

One of two continent-scale ice masses on Earth, the Greenland Ice Sheet is the largest body of ice in the Northern Hemisphere.

Almost 80 per cent of Greenland’s landmass is covered with ice.

It covers an area of 656,400 square miles (1.7 million square km), yet only meets the sea in a few areas where glaciers travel down fjords. 

If the entire ice sheet were to melt sea levels may rise up to 24ft, although experts say this is a highly unlikely scenario.

The other remaining ice shelves have also thinned and shrunk rapidly, with some retreating up to five miles (8.3km). 

The danger of these collapses is that they will increase the rate at which ice enters the ocean, which could have an enormous impact on sea levels. 

The ice shelves function like giant frozen dams, which hold back the glaciers from entering the sea.

Greenland is already responsible 17.3 per cent of the rise in sea levels between 2006 and 2018.

However, the glaciers of North Greenland are hosting enough ice to raise sea level by 6.6 feet (2.1 meters).

Writing in Nature Communications, the researchers, led by Romain Millan, said: ‘Overall, 25% of the ice sheet area is drained through former or remaining ice shelves, which represents a sea level rise equivalent of 2.1 m.

‘If the glaciers located in North Greenland lose the buttressing provided by ice shelves, the increase in discharge could rival the largest contributors to Greenland ice mass loss.’

Researchers say that the driving factor behind the rapid disintegration of Greenland’s ice sheet is rising ocean temperatures

The diagram shows how the front of the glaciers in the eight ice shelves have retreated over time. The dark green lines show the extent of ice in the 1990s while whiter lines show more recent extents

READ MORE: Global sea levels will rise by 4.6 FEET by 2150 if temperatures continue to rise at the current pace

Ocean temperatures in Western North Greenland increased modestly between 1965 and 2000, rising from 31.8°F (-0.1°C) to 32°F (0.0°C). 

However, between 2000 and 2015 ocean temperatures increased faster as they rose from 32°F (0.0°C) to 32.45°F (0.3°5C). 

In the North East, temperatures rose even faster and climbed from 32.7°F (0.4°C) to 34.2°F (1.2°C) between 1990 and 2020.

The authors added: ‘The observed increase in melting coincides with a distinct rise in ocean potential temperature, suggesting a strong oceanic control on ice shelves changes.’ 

Recent studies suggest that a worst case scenario in which global temperatures continue to rise at the current pace could see the oceans rise by an extra 4.6 feet by 2150.

If global emissions are only weakly cut, temperatures could triple according to scientists from Pusan National University in South Korea and Fabian Schloesser at the University of Hawaii.

Even limiting global warming to 3.6°F (2° C) above pre-industrial levels – a key aim of the Paris Agreement – would be insufficient to slow down the rate at which sea levels are rising.

Only by limiting global temperature increase below 3.2°F (1.8°C) relative to pre-industrial levels by the end of this century can sea level rise acceleration be avoided, the new study warns. 

If sea levels continue to rise at current rates then large parts of the United Kingdom could be at risk of flooding.

SEA LEVELS COULD RISE BY UP TO 4 FEET BY THE YEAR 2300



Global sea levels could rise as much as 1.2 metres (4 feet) by 2300 even if we meet the 2015 Paris climate goals, scientists have warned.

The long-term change will be driven by a thaw of ice from Greenland to Antarctica that is set to re-draw global coastlines.

Sea level rise threatens cities from Shanghai to London, to low-lying swathes of Florida or Bangladesh, and to entire nations such as the Maldives.

It is vital that we curb emissions as soon as possible to avoid an even greater rise, a German-led team of researchers said in a new report.

By 2300, the report projected that sea levels would gain by 0.7-1.2 metres, even if almost 200 nations fully meet goals under the 2015 Paris Agreement.

Targets set by the accords include cutting greenhouse gas emissions to net zero in the second half of this century.

Ocean levels will rise inexorably because heat-trapping industrial gases already emitted will linger in the atmosphere, melting more ice, it said.

In addition, water naturally expands as it warms above four degrees Celsius (39.2°F).

Every five years of delay beyond 2020 in peaking global emissions would mean an extra 8 inches (20 centimetres) of sea level rise by 2300.

‘Sea level is often communicated as a really slow process that you can’t do much about … but the next 30 years really matter,’ said lead author Dr Matthias Mengel, of the Potsdam Institute for Climate Impact Research, in Potsdam, Germany.

None of the nearly 200 governments to sign the Paris Accords are on track to meet its pledges.

Reference

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