Environment

Antarctic lake disappears after ice shelf fractures

Antarctic lake disappears afte...
Landsat 8 images show the Antarctic ice lake before (left) and after it drained
Landsat 8 images show the Antarctic ice lake before (left) and after it drained
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Landsat 8 images show the Antarctic ice lake before (left) and after it drained
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Landsat 8 images show the Antarctic ice lake before (left) and after it drained

An Antarctic lake holding twice the volume of water as San Diego Bay in California has vanished. An international team of scientists used satellite imagery to show that on the Amery Ice Shelf in East Antarctica, a lake containing an estimated 600 to 750 million cubic meters (21 to 26 billion cu ft) of water drained through the ice and into the ocean during the 2019 Antarctic winter.

Unless it involves dams breaking, one doesn't expect something like a full-size lake to simply disappear. However, the Antarctic ice cap isn't a normal place by everyday standards. Though the popular image of the region is one of unending snow and ice, lakes filled with meltwater form on the surface during the Antarctic summer.

According to the team, the lake in question was formed by decades of meltwater accumulating under a layer of ice that developed on the lake's surface in the winter darkness. It then underwent a process called hydrofracturing. That is, the weight of the growing body of water pressed down on the ice, causing it to fracture and allowing the water to quickly drain away into the ocean below. The surface ice layer then collapsed into the empty crater, known as an ice "doline", or sinkhole.

Such an event is rare, but not unheard of. However, this one is unusual not only because of the size of the lake but also because such water draining through ice as thick as 4,590 feet (1,400 m) is uncommon.

The event was observed by images from NASA's Landsat 8 and ICESat-2 satellites. The latter's green-light laser instrument transmits photon pulses and records the reflection point of each photon it receives back from Earth. This data allowed the team to calculate how far the ice layer collapsed and how the floating ice shelf rose by up to 118 ft (36 m) as the weight of the lake was removed.

In addition, the rising area created another lake, which drained directly into the crater at a rate of a million cubic meters (35.3 million cu ft) per day.

As well as being a curiosity, the vanishing lake also sheds light on the danger of widespread hydrofracturing resulting from a warming climate, which could cause ice shelves to collapse, releasing more meltwater to add to rising sea levels. The data gathered from the event could provide a better understanding of the frequency and evolution of deep lakes on the ice.

"It is exciting to see ICESat-2 show us details of processes that are occurring on the ice sheet at such fine spatial scale," says Helen Amanda Fricker, a glaciologist at Scripps Institution of Oceanography. "Since surface meltwater on ice shelves can cause their collapse which ultimately leads to sea-level rise when grounded ice is no longer held back, it’s important to understand the processes that weaken ice shelves."

The research was published in Geophysical Research Letters.

Source: Scripps Oceanography

10 comments
10 comments
VincentWolf
The global melting goes on and on like the energizer bunny and that is the problem friends--once it gains momentum it will be unstoppable. Goodbye Florida. Goodbye New Orleans. Goodbye DC. Goodbye New York. You think those areas can sue all the Republicans in the mid-West who argue global warming is a fake so that they don't have to give up their lucrative oil and gas leases on their farms and ranches? Yes, they will be sued.
wolf0579
I've been saying for years that someday the exec of oil corps will have bounties on their heads, and their memories will be reviled.
WonderingWhen
Guys, how do you get to work? Where does your food come from? This happened in the Antarctic winter. It is a natural process that has happened forever. The climate has been changing for 4.5 Billion years. There has been a snowball earth 2 or 3 times, then it warmed up. We need to do what is economically feasible, but I’m betting you have air conditioning? So chill.
Bruce Warren
A floating piece of ice, no matter how large, does not raise ocean levels when it melts. Frozen or melted the water weighs the same. Ice on land, like a glacier, does raise the ocean level when it melts.
Eric Snyman
Some of the commenters here didn't actually read the article. This had virtually NOTHING to do with global warming/climate change. I would have thought that New Atlas readers, unlike Facebook, would read an article before commenting on it.
bwana4swahili
A process that has been going on for millennia and will continue for millennia longer. Complaining about rising oceans doesn't accomplish anything; adapt or die has always been nature's way and this hasn't changed!
Catweazle
It is astonishing how many people seem to believe that perfectly normal weather events demonstrate imminent global catastrophe, and even more who fail to comprehend the implications of the Archimedes principle.
WillNC
Deniers deny that's what they do. Or the nothing newers yes apparently since the earth could hold water it has been freezing and melting, got it. But have you considered that about 8 billion humans now reside on the planet depending on relatively stable more or less temperate climate providing a roof over their heads and food on the table? Maybe and it will happen way sooner when the insurance companies won't insure and the banks won't lend then deniers and nothing newers will be angry, heads will roll.....
Signguy
Bruce Warren: A floating piece of ice, no matter how large, does not raise ocean levels when it melts. Frozen or melted the water weighs the same. Ice on land, like a glacier, does raise the ocean level when it melts.
THATS RIGHT PEOPLE! YOU FREAK OUT OVER NOTHING!
Kevin Ritchey
I’m so sorry to see some of the comments that people make while remaining ignorant of the facts. We are in very deep trouble. I’m saying this as I live next to Portland Oregon with the last 3-days experiencing the highest temperatures ever recorded in the city much less elsewhere in June. It’s hotter than Las Vegas and that’s in a desert. Better reconsider your knowledge gap before exposing your cognitive dissonance and ignorance.