Looking at Antarctica - sea ice report from Margo - 28 February, 2021

 Looking at the Calving of the Brunt Ice Shelf, Methane, Sea Ice & Climate with Margo (Feb. 28, 2021)

Margo reviews methane data from CAMS & NOAA for Saturday, 2/27/21. She also shows the current state of the Arctic and Antarctic sea ice and looks at Climate Reanalyzer and recent earthquakes. Margo shares an article on the recent calving of the Brunt Ice Shelf and shows it on NASA Worldview.

Daily Mail,

1 March, 2021

A large iceberg the size of Bedfordshire has broken away from the Antarctic, scientists have revealed.

The separation, which took place near Britain's Halley research station, saw the iceberg measuring 1,270 square kilometres break off from the Brunt Ice Shelf in a process called 'calving', the British Antarctic Survey (BAS) said.  

It comes almost a decade after scientists first detected vast cracks had formed in the shelf which is located in the Weddell Sea section of Antarctica.

The BAS, which has been operating the research station since 2017, said the first indication that a calving event was imminent came in November 2020 when a major crack - called the North Rift – carved its way through the ice. 

In January, the rift pushed northeast at up to 1 km per day and eventually an iceberg was formed when the crack widened in the morning of February 26 and split from the rest of the floating ice shelf. 

The movement has been relayed back to the research station's headquarters in Cambridge and scientists will be inspecting satellite imagery when it becomes available. 

According to NASA, the crack in the Brunt Ice Shelf was stable for nearly 35 years before it recently began accelerating.

While it is not the largest iceberg to split off from the Antarctic, it is the biggest chunk the Brunt Ice Shelf has lost since observations began more than 100 years ago in 1915.

Britain's Halley VI Research Station, which monitors the state of the vast floating ice shelf daily, said their team had been preparing for the calving 'for years'.

BAS director Jane Francis said: 'Our teams at BAS have been prepared for the calving of an iceberg from Brunt Ice Shelf for years. 

'We monitor the ice shelf daily using an automated network of high-precision GPS instruments that surround the station, these measure how the ice shelf is deforming and moving. We also use satellite images from ESA, NASA and the German satellite TerraSAR-X. 

+5

A crack called the North Rift formed on the Brunt Ice Shelf in Antarctica before the iceberg formed

Naive for sure, but a sign that with some people with little understanding of science the truth might be percolating through.

This is from the conspiracy (and almost 100% climate change denial site, Godlike Productions)

BREAKING NEWS: The opening scene from the movie “Day After Tomorrow” is playing out in real life as we speak!!!!!

Here’s the opening scene of the movie. It’s a doomy movie where a bunch of people die. 

This is the opening scene, and the start of epic doom unleashing upon the world.



Now here’s real life with the iceberg breaking off. Epic doom will follow 

just like the movie. .



They always have to show us beforehand before they pull the real events. It’s some sort of karma

 code for them.

World's largest ice shelf is melting 10 times faster than expected as the ocean around it soaks up heat from the sun

Two years ago on Radio NZ they made conclusion that the Antarctic "was not melting like the Arctic" at the very time when scientists were discovering the terrible rate of loss. 

All nonsense of course.

The truth was that the ice is being melted from underneath.

Radio New Zealand claims Antarctic ice is not melting like the Arctic

"Temperatures in the Antarctic Peninsula have increased by 4.5 degrees Fahrenheit (2.5 degrees Celsius) over the past 50 years — five times the rate of the rest of the planet. And scientists think that warm ocean waters could be melting Antarctica's glaciers as they flow under the floating tongues of ice."

Now, as the good scribes they are they report on this latest paper without any sense of context.

Ross Ice Shelf: part melting ten times faster than the rest

A part of the world's largest ice shelf is melting ten times faster than the rest of it, and water heated by the sun is responsible, a study shows.

Radio New Zealand,

30 April, 2019

The National Institute of Water and Atmospheric Research (NIWA) discovered the process happening to the Ross Ice Shelf in Antarctica as part of collaborative research which has just been published in the journal, Nature Geoscience.

NIWA marine physicists Mike Williams and Craig Stewart, and a team from the UK, studied the ice shelf for several years to record how it was melting, and what was causing it.

Dr Williams said the Ross Ice Shelf was about the size of France, and the northwest corner was melting much faster than the rest of the shelf - which was linked to summer heat from the top layer of the ocean


There is a large ocean expanse in front of the Ross Sea Ice Shelf which does not have sea ice because of strong offshore winds. This area, the Ross Sea Polynya, absorbs heat from the sun quickly in summer and drives very high levels of melt underneath the front of the ice shelf.

This is the first study to show how important the heat from the sun is for melting ice shelves, prior to this work it was thought to have only a minor affect.

"What we've always assumed is that the big ice shelves have very low melt rates, so this study changes that perspective and says actually there's another way in which these ice shelves are vulnerable, and if we're wanting to predict what might happen in the future, we need to understand and we need to include that in our modelling," Dr Williams said.


Floating ice shelves stabilise the parent ice sheet, and loss of the major ice shelves would lead to accelerating ice flow and sea-level rise of several metres or more.


Dr Williams said the ice shelf is right up against Ross Island which is a pinning point with the island holding the shelf there. If there are really high rates of melt around Ross Island and the shelf disconnects from the pinning point, then Dr Williams said the ice shelf would likely melt very rapidly and carve more icebergs after it detaches.


The team, including scientists from Cambridge University and the British Antarctic Survey, collected four years of data from an oceanographic mooring installed under the Ross Ice Shelf with instruments measuring temperature, salinity and currents.


Installing the mooring required drilling a hole through 260m of ice and then lowering it into 600m of ocean beneath the shelf.


The data showed that warm water from the upper layer of the open sea transports heat into the cavity under the ice shelf causing melt rates to nearly triple during summer.


Dr Williams said climate change was likely to result in less sea ice and higher surface ocean temperatures in the Ross Sea - which suggests that melt rates in this region will increase in the future.


"This study builds our understanding of the important but rarely observed processes that drive melting of ice shelves. Understanding and monitoring these processes is critical to predicting the future of the ice sheet and global sea level."

World's largest ice shelf is melting 10 times faster than expected as the ocean around it soaks up heat from the sun

• The Ross ice shelf is a floating slab of ice which juts into the Antarctic ocean 
• Loss of ice shelves results in glacier acceleration because it removes a barrier 
• Over 4 years researchers measured temperature, salinity, melt rate and currents
• The instruments showed that surface water heated by the sun flowed into the cavity under the ice shelf, causing melt rates almost to triple in the summer

DailyMail,

29 April, 2019

Part of the world's largest ice shelf is melting 10 times faster than expected due to the sea warming around it, research shows. 

The Ross Ice Shelf, a floating slab of Antarctic ice the size of France which juts into the ocean, is more vulnerable to global warming than previously thought.

The finding suggests that surface water heated by the sun also plays a crucial role in melting ice as well their exposure to warm deep ocean water, as is often thought. 

Looking at data over the course of four years, the researchers found that this water flowed under the ice shelf, causing melt rates to almost triple in the summer.

Loss of ice shelves removes a barrier to glaciers transporting water to the ocean, allowing sea levels to rise.

The team, from Cambridge University, spent several years investigating how the Ross Ice Shelf's north-west sector interacted with the ocean beneath it.

Former Cambridge scientist Doctor Craig Stewart, now at the National Institute of Water and Atmospheric Research (NIWA) said: 'The stability of ice shelves is generally thought to be related to their exposure to warm deep ocean water.

However, he and his team found that solar heated surface water also plays a 'crucial role' in melting ice shelves.

The team took measurements of temperature, salinity, melt rate and ocean currents using instruments passed through a 850 feet (260-metre) borehole.

Four years' worth of data were also collected from an oceanographic mooring installed under the ice shelf.

In addition, a custom-made radar system was employed to survey the changing thickness of the ice.

The instruments showed that surface water heated by the sun flowed into the cavity under the ice shelf, causing melt rates almost to triple in the summer.

Doctor Stewart added: 'Climate change is likely to result in less sea ice, and higher surface ocean temperatures in the Ross Sea, suggesting that melt rates in this region will increase in the future.' 

Dr Poul Christoffersen, from Cambridge University, pointed out that collapsing ice shelves can double or triple the speed at which glaciers flow to the ocean.

'The difference here is the sheer size of the Ross Ice Shelf, which is over 100 times larger than the ice shelves we've already seen disappear,' he said.

 'The observations we made at the front of the ice shelf have direct implications for many large glaciers that flow into the ice shelf, some as far as 900 kilometres (559 miles) away.' 

The findings are published in the latest issue of the journal Nature Geoscience.

https://www.nature.com/articles/s41561-019-0356-0?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ngeo%2Frss%2Fcurrent+%28Nature+Geoscience+-+Issue%29

Larsen C ice shelf about to expel iceberg into the ocean

A Delaware-Sized Iceberg is About to Enter the Southern Ocean — Loss of Larsen C Ice Shelf Possible in Near Future

Robertscribbler,

26 June, 2017

A rift in West Antarctica’s Larsen C Ice Shelf is about to expel a 1,000 foot tall, Delaware-sized iceberg into the Southern Ocean. The crack began to form in 2011. But over the past year, it has expanded rapidly. Now this massive, newly-forming iceberg hangs by just a thin 13 kilometer wide thread.

As you can see from the above Sentinel 1 animation posted by Adrian Luckman, rift progression has occurred in large leaps as pressure on the shelf reached various breaking points. New additions to the rift have often been in jumps of 20 kilometers or more of rift length in numerous instances over the past year. With just 13 kilometers of connecting ice remaining, the entire state-sized iceberg could now break off at any time.

According to Project Midas, late June observations show the crack continuing to widen at the rate of about 2 meters per day. So the larger section of the newly-forming berg is progressing toward the Southern Ocean at a rather rapid rate. And this movement is increasing strain on the small remaining ice bridge to the larger Larsen C Shelf.

Once the massive berg breaks off, researchers are concerned that it could precipitate a larger collapse of the Larsen C Ice Shelf itself. Such an event would be the third ice shelf loss along the Antarctic Peninsula during recent decades. A series of ice shelf collapses precipitated by warming oceans and atmospheres induced primarily by fossil fuel burning.

(Many cities are already suffering from rising ocean levels. However, future rates of sea level rise can increase considerably over present rates depending on how rapidly glaciers and ice shelves are taken down by human-forced warming. Image source: Taino.)

Such ice shelf losses are a rather serious affair as they release the glaciers behind them — allowing these massive ice forms to enter the world ocean more rapidly and thus increasing the rate of global sea level rise. Already, numerous cities, islands and nations are under threat from oceans presently rising at the rate of 3.3 millimeters per year globally. But loss of buttressing ice shelves like Larsen C and others around Antarctica and Greenland may double the present rate of rise many times over.

At a recent meeting of over 250 U.S. Mayors in Miami to discuss how climate change is presenting a serious threat to cities, New York’s Bill de Blasio told reporters: “Miami Beach is facing, literally, an existential crisis.” But it’s not just Miami that’s under the gun. It’s pretty much every coastal town, city, state and nation around the world. And Larsen C is just one of the most recent sea level rise canaries to begin to show signs of ailing in the global warming coal mine.

Links:

Project Midas

A New Crack in One of Antarctica’s Largest Ice Shelves Could Mean a Major Break is Near

Miami Beach Mayors Talk Global Warming

Tamino

Hat tip to Abel

Note: 1,000 foot tall reference includes freeboard + below water line measure.

New crack found in Larsen C uce shelf

New Crack Found in Delaware-Sized Chunk of Larsen C Ice Shelf as it Heads Toward Southern Ocean

A 2,000 square mile section of the Larsen C Ice Shelf is hanging by a thread as it continues to drift toward the Weddell Sea.

(A second crack develops in Larsen C Ice Shelf. Image source: Project MIDAS.)

Robertscribbler,

4 May, 2017

The break-off section represents fully 10 percent of all the ice contained in the Larsen C system. It has been divided from the larger ice shelf by a 180 kilometer long crack that began to develop in 2009 and that swiftly lengthened during recent years. Now only a 10 kilometer wide bridge links the breaking section to the larger ice shelf. And considering the enormous stresses now being placed on this break-off section it is expected to go at any time.

Since January, according to researchers at Project MIDAS, the large crack has been widening but its length growth has stalled. However, recent reports out this week from MIDAS found that a new crack had developed at the ice-bridge end of the break-off section. The new crack appears to be rounding the corner of the bridge to begin a quicker path to segmenting the massive ice berg away from Larsen C. A testament to the powerful forces that are inevitably forcing this enormous section of ice to relinquish its hold.

(Large section of Larsen C is moving far faster than the rest of the ice shelf toward the Southern Ocean. Image source: Project MIDAS.)

At issue is the fact that the break-off section is moving toward the Weddell Sea considerably faster than the rest of the Larsen C ice shelf. Much of this large section of ice is proceeding away from the Antarctic mainland at 3 meters per day. Surrounding sections of Larsen C are moving at only 1-2 meters per day. As a result, the toe end of the break-off mass is tipping out into Weddell’s waters and the crack separating it from Larsen C is widening.

It’s not really a question of if this massive block of ice will separate from Larsen C. More an issue of how soon.

Loss of so large a section of ice from Larsen C threatens the entire ice shelf’s stability. And some scientists are questioning whether the whole ice shelf will destabilize and eventually splinter — as happened to Larsen A and Larsen B during recent years.

(Rapid loss of buttressing ice shelves like Larsen C lock in higher and higher ranges for sea level rise. A worrying risk for rapid sea level rise occurs as global temperatures warm to between 1.5 and 2.5 C. A level we are fast approaching. Scientists like James Hansen identify a significant risk for multi-meter sea level rise this Century if 2 C warming thresholds are breached. Video Source: Carbon Freeze.)

Warming ocean waters due to human-forced climate change are the primary driver for loss of ice shelves around the world. These ice shelves hold back land glaciers — preventing them from more rapidly sliding into the world’s oceans. Larsen C alone holds back glaciers capable of lifting global ocean levels by 4 inches. But there are numerous such ice shelves and many are now facing thinning and increasing instability due to warming ocean waters. As a result, a growing number of scientists are concerned about the possibility for multi-meter sea level rise this Century if fossil fuel burning is not swiftly halted.

Links:

Project MIDAS

Carbon Freeze

Second Giant Crack Appears on Larsen C

Crack in Larsen C Forks

Larsen C Destabilization Could Trigger 4 Inch Sea Level Rise

Hat tip to June

Hat tip to Andy in San Diego

Towards the end of Larsen C ice shelf

Antarctica is About to Lose a 2,000 Square Mile Chunk of Ice — And it Could Mean the End of the Larsen C Ice Shelf

Robertscribbler,

10 January, 2017

It’s happened before. Ice shelves on the northern Antarctic Peninsula released large chunks of ice into the Southern Ocean as the world warmed up. They developed a concave shape which became unstable. Then they collapsed.

The ultimate collapse of Larsen A occurred in 1995. In 2002, further up the Antarctic Peninsula, the larger Larsen B Ice Shelf succumbed to the same fate. And it is thought that such losses haven’t happened to this section of Antarctica in at least 11,000 years and possibly as long ago as 100,000 years.

(NASA’s Jet Propulsion Laboratory provides this narrative describing the collapse of the Larsen B Ice Shelf in 2002. Video source: JPL.)

But in the present world, one where human fossil fuel emissions have forced global temperatures above 1 C hotter than 1880s averages, the stability of many of the great great ice shelves is now endangered.

Larsen C Ice Shelf to Calve 2,000 Square Mile Iceberg

Today, a huge rift has nearly bisected a large frontal section of the Larsen C Ice shelf — an ice system many times the size of its now deceased companions Larsen A and Larsen B. And during December — a period when Antarctica was warming into Austral Summer — this massive crack grew by 18 kilometers.

When, and not if, the crack reaches the ocean, a 2,000 square mile ice berg will float away from Larsen C. It will be one of the largest ice bergs ever to form in human memory. One the size of the state of Delaware. It will tower hundreds of feet above the ocean surface. And it will last for years before ultimately melting.

(The Larsen C is rift grew considerably — both lengthening and widening during December of 2016. It was an indication that a massive ice berg was about to break off. Image source: MIDAS.)

This event will change the geography of our world. And for this alteration alone, it has great consequence. But, as Chris Mooney notes in this excellent Washington Post article on the subject, it’s what happens afterward that really counts.

Event Could Presage Total Collapse

Of concern is the fact that once this massive ice berg calves off of Larsen C, the great ice sheet may become unstable. It will take on a concave form. This form will make it more vulnerable to further melt by warming waters running in toward the shelf. Furthermore, the large ice berg will take a chunk of Larsen C’s compressive arch with it. Such a compressive arch — like the arch of a flying buttress — helps to bear the weight of the shelf and keep it from smashing into thousands of tiny pieces. If too much of the arc is lost, the shelf can’t survive for long.

(Researchers at The MIDAS Project have projected that a 2,000 square mile section of the Larsen C Ice Shelf is about to break off. This section represents 10 percent of the Larsen C system. Its loss risks destabilization of the entire ice shelf. If Larsen C does disintegrate, it will release glaciers capable of increasing global sea level by another 4 inches. Image source: MIDAS.)

Glaciologist Eric Rignot notes in The Washington Post:

“We studied the current rift in the past few years, it has been progressing rather ‘normally,’ the recent acceleration in the rift progression is ‘expected’ in my opinion. The consequences on the rest of the ice shelf are not clear at this point. If the calving continues and goes past the compressive arch … then the ice shelf will break up.”

Scientists are currently divided over the issue of whether or not Larsen C’s near-term demise is imminent. However, the loss of such a massive ice berg from Larsen C, the present human-forced warming of the Antarctic land and ocean environment, and the presently observed thinning of the ice shelf all point toward a rising risk of destabilization or disintegration.

As with most things geological, you can’t really say that such an event is certain until after the fact. But as for Larsen C’s prospects of long term survival, things aren’t looking too great at the moment.

Links/Credits

The MIDAS Project

Antarctica is Set to Lose an Enormous Piece of Ice

An Ice Berg the Size of Delaware is About to Break off From Antarctica

NASA’s Jet Propulsion Laboratory