Satellite images reveal HUGE CRACKS in Antarctic ice sheet


New images taken by the ESA’s Copernicus Sentinel satellites shows two major new cracks in the West Antarctic Ice Sheet.

The cracks appeared on Pine Island Glacier, a part of the West Antarctic ice sheet which has been shedding rapidly increasing amount of ice into the ocean over the last 25 years.

Scientists anticipate the cracks, which measure over 20 kilometers long, could soon lead to the creation of an enormous new ice berg.

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The ESA's Copernicus Satellite program has captured images of cracks and ice berg calving on the Pine Island Glacier (pictured above)

The ESA’s Copernicus Satellite program has captured images of cracks and ice berg calving on the Pine Island Glacier (pictured above)

According to a report from the ESA, the ice velocity on the Pine Island Glacier currently exceeds 10 meters a day, leading to a series of major calving events in 1992, 1995, 2001, 2007, 2011, 2013, 2015, 2017, and 2018.

According to the ESA, the latest observed cracks appeared after the 2018 calving, which led to the creation of an enormous ice berg called B-46.

‘These new rifts appeared very soon after last year’s major calving of iceberg B46,’ the ESA’s Mark Drinkwater said.

‘Sentinel-1 winter monitoring of their progressive extension signals that a new iceberg of similar proportions will soon be calved.’

The B-46 iceberg separated from Pine Island Glacier last November and measured 66 square nautical miles, or 87 square miles, about three times the size of Manhattan.

Satellite imagery show Pine Island Glacier (pictured above) with no major rifts, or ice cracks, in 2018

Satellite imagery show Pine Island Glacier (pictured above) with no major rifts, or ice cracks, in 2018

New imagery from 2019 shows two 20-kilometer cracks (pictured above) in the sea ice on Pine Island Glacier

New imagery from 2019 shows two 20-kilometer cracks (pictured above) in the sea ice on Pine Island Glacier

Ice shelves, floating glacial ice areas that surround much of Antarctica, calve icebergs as part of the natural process of ice flowing out to sea.

The accelerating pace of calving events in recent years has helped driven rises in global sea levels.

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Pine Island and nearby Thwaites Glacier alone are contributing about 1 millimeter per decade to global sea level rise, as their flow of ice to the sea has accelerated in recent years, according to NASA research.

THE ANTARCTIC ICE CRISIS

Global sea levels are rising three times faster than a quarter of a century ago because of global warming, a study shows.

Ice losses from Antarctica have increased sea levels by almost 8mm (1/3 inch) since 1992, with two-fifths of this rise coming in the last five years alone.

The finds mean people in coastal communities are at greater risk of losing their homes and becoming so-called climate refugees than previously feared.

They are the result of a major climate assessment known as the Ice Sheet Mass Balance Inter-comparison Exercise (Imbie).

In one of the most complete pictures of Antarctic ice sheet change to date, an international team of 84 experts combined 24 satellite surveys to yield the results.

Study co-leader Professor Andrew Shepherd, of Leeds University, said: ‘We have long suspected that changes in Earth’s climate will affect the polar ice sheets.

One of these calving events produced another usual phenomenon, a neatly rectangular ice berg the size of Delaraware called A-68.

‘The berg was so clean-cut that it was reasonable to assume it might have very recently calved from the Larsen C ice shelf,’ NASA said, referring to another ice sheet near the West Antarctic Ice Sheet.

The iceberg was spotted on October 16, 2018, during a flight for Operation IceBridge -NASA’s long-running aerial survey of polar ice.

During that day’s survey of glaciers and ice shelves along the northern Antarctic Peninsula, scientist Jeremy Harbeck spotted the compelling berg.

Not only were the edges of the iceberg extremely straight, but the two corners appeared ‘squared off’ at right angles.

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Scientists used images from Landsat 8 and the European Space Agency’s Sentinel-1 to trace the berg back to its origins.

The berg cruised all the way north and through a narrow passage between the A-68’s northern tip and a rocky outcrop near the ice shelf known as Bawden Ice Rise. NASA/UMBC glaciologist Chris Shuman likens this zone to a nutcracker.

A-68 has repeatedly smashed against the rise and caused pieces of ice to splinter into clean-cut geometric shapes. 

By November 2018 the iceberg had moved out of the rubble zone and into open water.

Shuman said: ‘Now it’s just another iceberg on its way to die.’

A second rectangular berg, known as a ‘tabular’ iceberg, was spotted off the east coast of the Antarctic Peninsula, near the Larsen C ice shelf and close to the first one.

It is part of a large ‘field of bergs NASA experts may have recently broken off the shelf, and say the sharp angles and flat surfaces are evidence the break occurred very recently.

The breakup produced a number of striking, tabular ice bergs.

In an interview with LiveScience, NASA scientist Kelly Brunt said ‘tabular icebergs are rather like fingernails that crack of, giving them sharp edges.  

The largest observed ice berg in the world, the B-15, was calved from Antarctica in March of 2000 and measured more than 4.200 square miles.

By last year, B-15 had drifted north toward South America and lost almost all of its mass, diminished to just 50 square nautical miles. 

THE RECTANGULAR BERG’S INCREDIBLE JOURNEY

It calved from the ice shelf’s new front in early November 2017, just a few months after A-68 broke away.   

The rectangle berg then began a northward journey, navigating the newly open water between the Larsen C ice shelf and Iceberg A-68. 

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Collision threats were everywhere: A-68 could smash into the little bergs at any time, and smaller bergs could collide with each other.

The berg cruised all the way north and through a narrow passage between the A-68’s northern tip and a rocky outcrop near the ice shelf known as Bawden Ice Rise. NASA/UMBC glaciologist Chris Shuman likens this zone to a nutcracker. 

An area of geometric ice rubble is visible in the Landsat 8 image  from October 14, 2018, two days before the IceBridge flight. A-68 has repeatedly smashed against the rise and caused pieces of ice to splinter into clean-cut geometric shapes. The once-long rectangle berg did not make it through unscathed; it broke into smaller bits. The iceberg in Harbeck’s photograph, circled in the annotated Landsat 8 satellite image, appears closer to the shape of a trapezoid. The trapezoidal berg is about 900 meters wide and 1500 meters long, which is tiny compared to the Delaware-sized A-68.

An area of geometric ice rubble is visible in the Landsat 8 image from October 14, 2018, two days before the IceBridge flight. A-68 has repeatedly smashed against the rise and caused pieces of ice to splinter into clean-cut geometric shapes. The once-long rectangle berg did not make it through unscathed; it broke into smaller bits. The iceberg in Harbeck’s photograph, circled in the annotated Landsat 8 satellite image, appears closer to the shape of a trapezoid. The trapezoidal berg is about 900 meters wide and 1500 meters long, which is tiny compared to the Delaware-sized A-68.

A-68 has repeatedly smashed against the rise and caused pieces of ice to splinter into clean-cut geometric shapes. 

An area of geometric ice rubble is visible in the Landsat 8 image from October 14, 2018, two days before the IceBridge flight.

The once-long rectangle berg did not make it through unscathed; it broke into smaller bits. 

The iceberg in Harbeck’s photograph, circled in the annotated Landsat 8 satellite image, appears closer to the shape of a trapezoid. 

The trapezoidal berg is about 900 meters wide and 1500 meters long, which is tiny compared to the Delaware-sized A-68.

By November 2018 the iceberg had moved out of the rubble zone and into open water.  



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