- Experts determined that the A68 iceberg that separated from Antarctica’s Larsen C ice shelf in July 2017 was caused by ice thinning.
- This layer is weakening due to the movement of ocean water under the ice shelves and climate change.
- When the ice mixture thinned, the crack was 249 ft. increased to 367 feet
Experts believe that the Delaware-sized A68 iceberg that separated from Antarctica’s Larsen C ice shelf in July 2017 was probably caused by a thinning of the crust of muddy frozen water that normally heals cracks. Used to give
Glaciologists from the University of California, Irvine and NASA’s JPL determined that the ice layer is weakening due to a two-pronged attack on the ice, the movement of ocean water beneath the ice layers, and climate change.
Looking at 11 cracks in the Larsen C ice shelf, they created three scenarios: if the ice shelf is thinning from melting; If the ice mixture became thin; If both the snow cover and the tincture became thinner.
Experts have determined that the Delaware-sized A68 iceberg that separated from Antarctica’s Larsen C ice shelf in July 2017 was caused by a thinning of a layer of slushy frozen water that would normally have healed cracks.
Once the ice mixture thinned, the crack widened, increasing from 249 feet to 367 feet.
When both the ice shelf and the admixture were thinned, the crack widened, but to a lesser extent.
And while the ice mail helped heal cracks in the thin ice shelf, the gap was cut down from 259 feet to 72 feet.
This layer is weakening due to the movement of ocean water under the ice shelves and climate change.
When the ice mixture thinned, the crack was 249 ft. increased to 367 feet
The lead author of the study, NASA’s JPL researcher Eric Larour, said: “Initially, the adulterant is thinner than ice. Statement.
‘When the melange is only 10 or 15 meters thick, it is like water, and the ice shelf begins to crack and crack.’
The differences in the three states are due to the different nature of the substances, Larour said.
In winter, warm ocean water can collide with the mantle below and extend the crack to the entire ice shelf.
‘The prevailing theory behind the increase in large iceberg calving events in the Antarctic Peninsula has been hydrofracturing, in which molten pools at the surface allow water to seep through cracks in the ice shelf, which expand when the water re-freezes. ‘ said Rignot.
‘But that theory fails to explain how iceberg A68 might have broken off from the Larsen C ice shelf in the dead of Antarctic winter, when no melt pool was present.’
In February, NASA images showed that the A68 iceberg disintegrated into an ‘alphabet soup’ of individual fragments as it drifted into the ocean north of Antarctica.
Given that these ice shelves are thought to prevent glaciers from entering the ocean, any weakening of the ice could accelerate ocean uplift and further destabilize the ice shelves.
Eric Rignot, one of the study’s co-authors, said in a statement, “The thinning of the ice floe that affixes large volumes of floating ice shelves together is another way that climate change can affect the ice of Antarctica.” can cause a rapid retreat of the shelves.
‘With this in mind, we may need to reconsider our estimates about the timing and extent of sea level rise from polar ice loss – that is, it could come sooner and have a bigger bang than expected. can.’
The researchers used NASA’s ice-sheet and sea-level system models, as well as observations from NASA’s Operation IceBridge mission and observations from NASA and European satellites.
‘A lot of people instinctively thought, “If you dilute the ice shelf, you’re going to make it more fragile, and it’s going to break,” Laour said.
Rignot said, ‘We have finally begun to look for an explanation as to why these ice shelves began to recede and come into these configurations, which had become unstable decades before hydrofracturing was acted upon.
‘Although the thinning of the ice is not the only process explaining it, it is sufficient to account for the decline we observed.’
The study has been published in Proceedings of the National Academy of Science.
What is the A-68 iceberg and what caused it to break away from Antarctica?
In July 2017, a massive crack in Antarctica’s Larsen C ice shelf caused a trillion-ton iceberg – the third largest ever recorded – to break away from the icy southern continent.
The giant mass of ice, called iceberg A-68, measures 5,800 square kilometers (2,240 sq mi), making it around the size of Delaware, or four times the area covered by Greater London.
As the A-68 broke up, it is unclear what would happen to the enormous mass, with fears that it might break into pieces too small to be tracked on a satellite, and flow into the shipping lane.
In July 2017, a massive crack in Antarctica’s Larsen C ice shelf caused a trillion-ton iceberg – the third largest ever recorded – to break away from the icy southern continent. These detailed images were captured by instruments aboard NASA’s Landsat 8 satellite
Experts have found that the cracks are still growing in Larsen C, and if they continue to grow, it is possible that the ice shelf could collapse.
If the Sarah Larsen C collapses, the ice it holds could add another 4 inches (10 cm) to global sea levels over the years.
Many scientists argue that a calving event was not necessarily due to climate change.
Instead, it may simply reflect the natural growth and decay cycle of an ice shelf.