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Katie Mettler, The Washington Post
February 25, 2019
A chasm and a crack on the Brunt ice shelf in Antarctica are getting closer and closer, and when the two finally meet, a plate of ice two times larger than New York City will come off and float to the large.
The two glacial faults are about 2.5 miles apart and it may take days or months to find them at last. But when they do, the iceberg that forms in the Weddell Sea will not be the largest in orbit of Antarctica. In fact, it might not even be in the top 20 history.
Its size is not what makes it remarkable: this is what the break itself says about the natural process of calving icebergs, about how climate change could destabilize other ice trays like Brunt and about how the movement could jeopardize the critical scientific research done by locals there for more than 60 years.
Since 1956, British scientists have been studying geology, glaciology and the atmosphere at Halley Research Station on Brunt Sea Ice. The laboratory has been destroyed and rebuilt several times over the decades. It took its most recent form in 2012 when the Halley VI research station – a mobile modular structure – delivered its first scientific data.
The same year, satellite monitoring showed that a vast chasm in the pack ice – officially called Chasm 1 – was expanding for the first time in more than three decades. According to the definition of a glaciologist, an abyss is described as a very large fissure that visibly crosses the sea ice to the sea.
If it continued to grow, Chasm 1 would eventually block Halley VI station. The British Antarctic Survey has therefore decided to move its researchers further inland and at a safe distance from the abyss for several months in 2016 and 2017.
But in October 2016, another crack, called Halloween, was quickly formed 17 kilometers north of the research station and continues to expand eastward.
In the two years since then, Chasm 1 's is close to the Halloween crack, preparing scientists for the inevitability of an iceberg break that could have consequences. more serious on the stability of the entire ice shelf Brunt. NASA predicts that the mass could extend over 1,700 square kilometers (660 square miles), making it the largest iceberg to separate from the Brunt Ice Shelf in more than 100 years.
"It's a big iceberg, but it's not a huge iceberg – not from an Antarctic point of view," said Christopher Shuman, a researcher at the University of Maryland's Joint Ground Systems Technology Center. Baltimore at NASA. "The impact on the region is the reactivation of these divisions and we do not know why. A new fault (Halloween crack) has formed what has been thought to be a pretty stable ice shelf. "
According to Helen Fricker, a glaciologist at the Scripps Institution of Oceanography, scientists have been studying glacier trays for a little over 100 years. It is therefore difficult to say whether icebergs regenerate faster at this point in the Brunt ice floe.
"I do not think you can link a calving event to climate change," said Fricker. "This does not mean that Antarctica is not undergoing rapid change related to climate change. But it's in another part of Antarctica.
Calving icebergs is a natural and natural process that helps maintain the net land mass of Antarctica. Floating ice shelves line the shores of the continent and grow outward as the snow falls. (You can see how the Brunt Ice Shelf grew up here.)
"That's how Antarctica works," said Fricker. "Icebergs come and icebergs go."
Research shows that on the west coast of the continent, where the waters are warmer than those of Brunt, the pack ice has cleared. In this region, scientists say that climate change has a clear role.
On the Brunt, Halley VI and its inhabitants are not threatened in the immediate future. Its current location is outside the expected iceberg, but a spokesman for the British Antarctic Survey said researchers were monitoring changes to the structural integrity of the pack ice.
Part of this monitoring included the precautionary measure of closure of operations at the research station during the last three Antarctic winters, characterized by months of darkness and heavy snowfall. Under these conditions, it would be more dangerous to launch a rescue mission if the cracks and abysses jeopardized the safety of Halley VI researchers.
The staff members are preparing to leave for the winter of 2019.
"Emergency plans are in place if the ice conditions were to change significantly before the departure of the station staff," the British Antarctic Survey told the Washington Post in a statement. "The station is designed to be relocated. The frequency of offshoring depends very much on how the ice behaves in the future. "
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