Environment

Antarctica's newest giant iceberg may destabilize the ice shelf

A huge chunk of the Larsen C ice shelf broke off last month, but researchers say this might not be the end of the story
A huge chunk of the Larsen C ice shelf broke off last month, but researchers say this might not be the end of the story
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A huge chunk of the Larsen C ice shelf broke off last month, but researchers say this might not be the end of the story
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A huge chunk of the Larsen C ice shelf broke off last month, but researchers say this might not be the end of the story

On July 12, a giant iceberg was born as a chunk some 6,000 km2 (2,300 mi2) broke away from the Larsen C ice shelf in Antarctica. The breakup was the result of an 18-month suspense story, as scientists watched the crack extend across the ice. But with the berg now adrift and satellites continuing to monitor the site, it seems the saga isn't over yet: the remaining cracks are spreading towards a feature that's integral to the stability of the rest of the ice shelf.

Several satellites have been watching the site for months to study the effects of climate change on the region, and now that there's a huge new iceberg floating around, they're tracking its movements to keep any shipping lane chaos to a minimum. So far, the berg, which has been officially named A68, has drifted about 5 km (3.1 mi) away from the remaining shelf.

Larsen C lost about 10 percent of its area after the calving, with the event also creating at least 11 smaller icebergs up to 13 km (8 mi) long, splintering off from both A68 and the mainland. But that number could be set to rise as a network of cracks creeps across the ice towards a key part of the landscape.

"The satellite images reveal a lot of continuing action on Larsen C Ice Shelf," says Anna Hogg, a researcher at the University of Leeds. "We can see that the remaining cracks continue to grow towards a feature called Bawden Ice Rise, which provides important structural support for the remaining ice shelf. If an ice shelf loses contact with the ice rise, either through sustained thinning or a large iceberg calving event, it can prompt a significant acceleration in ice speed, and possibly further destabilization. It looks like the Larsen C story might not be over yet."

The researchers are careful not to claim that the breakaway was a direct result of climate change, since the rate of collapse isn't entirely unprecedented. This kind of thing happens naturally during the life cycle of ice shelves, but it may have been accelerated by changing environmental conditions. Satellites will continue to monitor the area to learn about the processes at work.

"Although floating ice shelves have only a modest impact on of sea-level rise, ice from Antarctica's interior can discharge into the ocean when they collapse," says Hilmar Gudmundsson, a researcher from the British Antarctic Survey. "Consequently we will see increase in the ice-sheet contribution to global sea-level rise. With this large calving event, and the availability of satellite technology, we have a fantastic opportunity to watch this natural experiment unfolding before our eyes. We can expect to learn a lot about how ice shelves break up and how the loss of a section of an ice shelf affects the flow of the remaining parts."

A paper on the calving event was published in the journal Nature Climate Change, and the speed of the breakup can be seen in the video below.

Source: University of Leeds

Larsen-C giant iceberg breaks away

7 comments
ThomasEdwardMiller
It seems one has to reduce solar energy from entering oceans and warming them. Almost all solar energy falling on the ocean is absorbed unless solar elevation angles are small. As I have said before, creating a spray mist over the oceans prevents solar absorption by the ocean, to a significant extent. Mist and clouds absorb some ultra viloet, some visible light and a lot of infrared radiation from the sun. Floating spray mist pumps would be very good.
Bob
Somehow this all reminds me of coffee. A few years ago scientists were telling us that coffee was really bad for us. Today they say a few cups a day is good for us and prevents a number of health problems. I can just imagine that in the next few years there will be some volcanic eruptions, changes in ocean currents or reduction in solar radiation that will start cooling the earth and all these scientists will be telling us to burn more fossil fuels to increase CO2 to stop global cooling. History does repeat itself.
owlbeyou
I can just see all the naysayers of climate change getting their knickers in a twist and claiming that this ice shelf calving is not all it's cracked up to be. :)
Lardo
"The researchers are careful not to claim that the breakaway was a direct result of climate change ... ... but it may have been accelerated by changing environmental conditions." "Changing environmental conditions"... i.e. climate change. "Consequently we will see increase in the ice-sheet contribution to global sea-level rise." How many times, over the last 20 years or so, have we been told that this, that, and the other thing, would lead to global sea-level rise? And yet they haven't. Label me a "naysayer of (man-made) climate change".
CharlieSeattle
Ice flows already in the sea that break away will not raise seal levels. However, If Glaciers high on land, that the sea ice locked in place is now free to flow to the sea. The freed glacier ice will raise sea levels.
Wolf0579
For all you climate deniers out there... one, you're reading this over the web. A Product of Science. It Works. Two, If you distrust science, immediately give up your cell phones. It doesn't take genius to anticipate your reaction.
Grunchy
The thing about climate change is that it's possibly another correlation/causation error. Just because two things happen at the same time doesn't mean they are directly related. Just because you pray to a god at some point, and you happened to experience some good luck, doesn't necessarily mean there's a god in hiding somewhere secretly listening into your thoughts to give you rewards (doesn't disprove it either). So just because the Earth is experiencing high CO2 emissions and global warming at the same time doesn't mean they are correlated or have a causation relationship; nor does it disprove it. If you scrutinize climate science, there's a pretty weak case that higher CO2 concentration has any effect on the radiative emissivity of the planet as a whole; which is really the crux of the issue. Has anyone read the Chicken Little story? Yes sure, go tell the King that the sky is falling; but if the mathematics isn't compelling, why should anybody listen? (The thing about an actual greenhouse: the plants inside absorb the CO2 and emit a lot of O2 gas. So is it the high O2 concentration that causes the high temp inside the greenhouse? Or is it the glass that actually traps the heat. Things that make you go "hmm".)
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