Breaking- West Antarctic ice sheetin peril

[Old Rocks]

Antarctic ice-sheet loss driven by basal melting of ice shelves

• H. D. Pritchard,
• S. R. M. Ligtenberg,
• H. A. Fricker,
• D. G. Vaughan,
• M. R. van den Broeke
• & L. Padman

• Affiliations
• Contributions
• Corresponding author

Nature

484,

502–505

(26 April 2012)

doi:10.1038/nature10968

Accurate prediction of global sea-level rise requires that we understand the cause of recent, widespread and intensifying1, 2 glacier acceleration along Antarctic ice-sheet coastal margins3. Atmospheric and oceanic forcing have the potential to reduce the thickness and extent of floating ice shelves, potentially limiting their ability to buttress the flow of grounded tributary glaciers4. Indeed, recent ice-shelf collapse led to retreat and acceleration of several glaciers on the Antarctic Peninsula5. But the extent and magnitude of ice-shelf thickness change, the underlying causes of such change, and its link to glacier flow rate are so poorly understood that its future impact on the ice sheets cannot yet be predicted3. Here we use satellite laser altimetry and modelling of the surface firn layer to reveal the circum-Antarctic pattern of ice-shelf thinning through increased basal melt. We deduce that this increased melt is the primary control of Antarctic ice-sheet loss, through a reduction in buttressing of the adjacent ice sheet leading to accelerated glacier flow2. The highest thinning rates occur where warm water at depth can access thick ice shelves via submarine troughs crossing the continental shelf. Wind forcing could explain the dominant patterns of both basal melting and the surface melting and collapse of Antarctic ice shelves, through ocean upwelling in the Amundsen6 and Bellingshausen7 seas, and atmospheric warming on the Antarctic Peninsula8. This implies that climate forcing through changing winds influences Antarctic ice-sheet mass balance, and hence global sea level, on annual to decadal timescales.

Yet this is what is being observed.

 

[flacaltenn]

Antarctic ice-sheet loss driven by basal melting of ice shelves

• H. D. Pritchard,
• S. R. M. Ligtenberg,
• H. A. Fricker,
• D. G. Vaughan,
• M. R. van den Broeke
• & L. Padman

• Affiliations
• Contributions
• Corresponding author

Nature

484,

502–505

(26 April 2012)

doi:10.1038/nature10968

Accurate prediction of global sea-level rise requires that we understand the cause of recent, widespread and intensifying1, 2 glacier acceleration along Antarctic ice-sheet coastal margins3. Atmospheric and oceanic forcing have the potential to reduce the thickness and extent of floating ice shelves, potentially limiting their ability to buttress the flow of grounded tributary glaciers4. Indeed, recent ice-shelf collapse led to retreat and acceleration of several glaciers on the Antarctic Peninsula5. But the extent and magnitude of ice-shelf thickness change, the underlying causes of such change, and its link to glacier flow rate are so poorly understood that its future impact on the ice sheets cannot yet be predicted3. Here we use satellite laser altimetry and modelling of the surface firn layer to reveal the circum-Antarctic pattern of ice-shelf thinning through increased basal melt. We deduce that this increased melt is the primary control of Antarctic ice-sheet loss, through a reduction in buttressing of the adjacent ice sheet leading to accelerated glacier flow2. The highest thinning rates occur where warm water at depth can access thick ice shelves via submarine troughs crossing the continental shelf. Wind forcing could explain the dominant patterns of both basal melting and the surface melting and collapse of Antarctic ice shelves, through ocean upwelling in the Amundsen6 and Bellingshausen7 seas, and atmospheric warming on the Antarctic Peninsula8. This implies that climate forcing through changing winds influences Antarctic ice-sheet mass balance, and hence global sea level, on annual to decadal timescales.

Yet this is what is being observed.

So what part of

But the extent and magnitude of ice-shelf thickness change, the underlying causes of such change, and its link to glacier flow rate are so poorly understood that its future impact on the ice sheets cannot yet be predicted3

...... caused you to leap to the conclusion that it is being observed and will accelerate?

"Warm water at depth?" --- Southern ocean surface chart doesn't SHOW any warming in over 30 years. Is there REALLY a submarine hot layer? Show it to me...

 

[Old Rocks]

Ocean access to a cavity beneath Totten Glacier in East Antarctica

• J. S. Greenbaum,
• D. D. Blankenship,
• D. A. Young,
• T. G. Richter,
• J. L. Roberts,
• A. R. A. Aitken,
• B. Legresy,
• D. M. Schroeder,
• R. C. Warner,
• T. D. van Ommen
• & M. J. Siegert

• Affiliations
• Contributions
• Corresponding author

Nature Geoscience

8,

294–298

(2015)

doi:10.1038/ngeo2388
Received

12 December 2014
Accepted

09 February 2015
Published online

16 March 2015

Totten Glacier, the primary outlet of the Aurora Subglacial Basin, has the largest thinning rate in East Antarctica1, 2. Thinning may be driven by enhanced basal melting due to ocean processes3, modulated by polynya activity4, 5. Warm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica6, has been observed in summer and winter on the nearby continental shelf beneath 400 to 500 m of cool Antarctic Surface Water7, 8. Here we derive the bathymetry of the sea floor in the region from gravity9 and magnetics10 data as well as ice-thickness measurements11. We identify entrances to the ice-shelf cavity below depths of 400 to 500 m that could allow intrusions of warm water if the vertical structure of inflow is similar to nearby observations. Radar sounding reveals a previously unknown inland trough that connects the main ice-shelf cavity to the ocean. If thinning trends continue, a larger water body over the trough could potentially allow more warm water into the cavity, which may, eventually, lead to destabilization of the low-lying region between Totten Glacier and the similarly deep glacier flowing into the Reynolds Trough. We estimate that at least 3.5 m of eustatic sea level potential drains through Totten Glacier, so coastal processes in this area could have global consequences.

Seems the more we find out, the worse the situation looks.

 

[Old Rocks]

Sea levels to rise as West Antarctic ice sheet melts - Cool Australia

The melting of the glacier is already one of the biggest contributors to sea-level rise globally, shedding 52 gigatonnes of ice a year, or about half of West Antarctica’s losses.

Thwaites Glacier will likely add less than a quarter of millimetre of sea-level rise a year over the next century but a rapid collapse would quadruple the rate and ”probably spill over into adjacent catchments, undermining much of West Antarctica”, scientists from the University of Washington’s Polar Science Centre said in their Science paper. Current sea-level rise is about three millimetres a year.

While modelling ”suggests a full-scale collapse of this sector may be inevitable, it leaves large uncertainty in the timing”, the researchers said. Full collapse may take 200-900 years.

The thinning ice is largely caused by warming offshore waters reaching under the ice floating at the continental margins. As reported in Fairfax Media on Monday, Australian researchers have found the band of westerly winds known as the Roaring Forties have quickened and moved closer to Antarctica, drawing up relatively warm waters from below the surface.

Even normally cold waters are around -1.5 to -1.8 degrees and warm enough to melt ice under pressure, said Tas van Ommen, a glaciologist with the Australian Antarctic Division.

Water now entering the continental shelf is ”hot” by comparison, at 0.5-1.2 degrees. ”It is this intrusion that is the strong threat,” Dr van Ommen said.

Exacerbating the problem is the area’s geography, with much of the ice sitting on bedrock that slopes inland, meaning the sheet gets thicker as the melt line moves closer to land.

Interesting.

 

[flacaltenn]

Sea levels to rise as West Antarctic ice sheet melts - Cool Australia

The melting of the glacier is already one of the biggest contributors to sea-level rise globally, shedding 52 gigatonnes of ice a year, or about half of West Antarctica’s losses.

Thwaites Glacier will likely add less than a quarter of millimetre of sea-level rise a year over the next century but a rapid collapse would quadruple the rate and ”probably spill over into adjacent catchments, undermining much of West Antarctica”, scientists from the University of Washington’s Polar Science Centre said in their Science paper. Current sea-level rise is about three millimetres a year.

While modelling ”suggests a full-scale collapse of this sector may be inevitable, it leaves large uncertainty in the timing”, the researchers said. Full collapse may take 200-900 years.

The thinning ice is largely caused by warming offshore waters reaching under the ice floating at the continental margins. As reported in Fairfax Media on Monday, Australian researchers have found the band of westerly winds known as the Roaring Forties have quickened and moved closer to Antarctica, drawing up relatively warm waters from below the surface.

Even normally cold waters are around -1.5 to -1.8 degrees and warm enough to melt ice under pressure, said Tas van Ommen, a glaciologist with the Australian Antarctic Division.

Water now entering the continental shelf is ”hot” by comparison, at 0.5-1.2 degrees. ”It is this intrusion that is the strong threat,” Dr van Ommen said.

Exacerbating the problem is the area’s geography, with much of the ice sitting on bedrock that slopes inland, meaning the sheet gets thicker as the melt line moves closer to land.

Interesting.

Ah.. The ocean ate the warming. Disappeared into the depths and the WINDS blew 100m deep ocean warmth towards the West Shelf.. A lot of moving parts there G-Rocks. And that "deep ocean warmth" was likely the consequence of the relative Solar Maximum that ended in the 1960s --- NOT CO2...

 

[flacaltenn]

Sea levels to rise as West Antarctic ice sheet melts - Cool Australia

The melting of the glacier is already one of the biggest contributors to sea-level rise globally, shedding 52 gigatonnes of ice a year, or about half of West Antarctica’s losses.

Thwaites Glacier will likely add less than a quarter of millimetre of sea-level rise a year over the next century but a rapid collapse would quadruple the rate and ”probably spill over into adjacent catchments, undermining much of West Antarctica”, scientists from the University of Washington’s Polar Science Centre said in their Science paper. Current sea-level rise is about three millimetres a year.

While modelling ”suggests a full-scale collapse of this sector may be inevitable, it leaves large uncertainty in the timing”, the researchers said. Full collapse may take 200-900 years.

The thinning ice is largely caused by warming offshore waters reaching under the ice floating at the continental margins. As reported in Fairfax Media on Monday, Australian researchers have found the band of westerly winds known as the Roaring Forties have quickened and moved closer to Antarctica, drawing up relatively warm waters from below the surface.

Even normally cold waters are around -1.5 to -1.8 degrees and warm enough to melt ice under pressure, said Tas van Ommen, a glaciologist with the Australian Antarctic Division.

Water now entering the continental shelf is ”hot” by comparison, at 0.5-1.2 degrees. ”It is this intrusion that is the strong threat,” Dr van Ommen said.

Exacerbating the problem is the area’s geography, with much of the ice sitting on bedrock that slopes inland, meaning the sheet gets thicker as the melt line moves closer to land.

Interesting.

You know what else changes as the grounding line moves up out of depths and closer to land??












The exposure to these deep warm well-ups...
They know this. They're just sticking to the plot line..

 

[flacaltenn]

Shit... I forgot.. I don't DO ice...

 

[Crick]

Why are we treating the uncheckable collapse of the WAIS as new news? This came out in early 2014.

From Wikipedia's article on the WAIS

Potential collapse
Large parts of the WAIS sit on a bed which is below sea level and slopes downward inland.[A] This slope, and the low isostatic head, mean that the ice sheet is theoretically unstable: a small retreat could in theory destabilize the entire WAIS leading to rapid disintegration. Current computer models do not include the physics necessary to simulate this process, and observations do not provide guidance, so predictions as to its rate of retreat remain uncertain. This has been known for decades.[9]

In January 2006, in a UK government-commissioned report, the head of the British Antarctic Survey, Chris Rapley, warned that this huge west Antarctic ice sheet may be starting to disintegrate. It has been hypothesised that this disintegration could raise sea levels by approximately 3.3 metres (11 ft).[10] (If the entire West Antarctic Ice Sheet were to melt, this would contribute 4.8 m (16 ft) to global sea level.)[11] Rapley said a previous (2001) Intergovernmental Panel on Climate Change(IPCC) report that played down the worries of the ice sheet's stability should be revised. "I would say it is now an awakened giant. There is real concern." [5]

Rapley said, "Parts of the Antarctic ice sheet that rest on bedrock below sea level have begun to discharge ice fast enough to make a significant contribution to sea level rise. Understanding the reason for this change is urgent in order to be able to predict how much ice may ultimately be discharged and over what timescale. Current computer models do not include the effect of liquid water on ice sheet sliding and flow, and so provide only conservative estimates of future behaviour." [12]

James E. Hansen, a senior NASA scientist and leading climate expert, said the results were deeply worrying. "Once a sheet starts to disintegrate, it can reach a tipping pointbeyond which break-up is explosively rapid," he said.[13]

Polar ice experts from the U.S. and U.K. met at the University of Texas at Austin in March, 2007 for the West Antarctic Links to Sea-Level Estimation (WALSE) Workshop.[14] The experts discussed a new hypothesis that explains the observed increased melting of the West Antarctic Ice Sheet. They proposed that changes in air circulation patterns have led to increased upwelling of warm, deep ocean water along the coast of Antarctica and that this warm water has increased melting of floating ice shelves at the edge of the ice sheet.[15] An ocean model has shown how changes in winds can help channel the water along deep troughs on the sea floor, toward the ice shelves of outlet glaciers.[16] The exact cause of the changes in circulation patterns is not known and they may be due to natural variability. However, this connection between the atmosphere and upwelling of deep ocean water provides a mechanism by which human induced climate changes could cause an accelerated loss of ice from WAIS.[16] Recently published data collected from satellites support this hypothesis, suggesting that the west Antarctic ice sheet is beginning to show signs of instability.[4][17]

On 12 May 2014, It was announced that two teams of scientists said the long-feared collapse of the Ice Sheet had begun, kicking off what they say will be a centuries-long, "unstoppable" process that could raise sea levels by 1.2 to 3.6 metres (3.9–11.8 ft)[18][19] They estimate that rapid drawdown of Thwaites Glacier will begin in 200 – 1000 years.[20](Scientific source articles: Rignot et al. 2014 [21] and Joughin et al. 2014.[22])

 

[Two Thumbs]

so in 2100 we are all, finally, doomed.


about fucking time.

 

[Whirled Publishing]

Volcanic sea floor eruptions - around the world - have increased exponentially over the past several years - along with an alarming increase in volcanic activity above the surface of the oceans. Six volcanic islands emerged from the sea floor in under two years, for example, along with the pumice floating off the coast of New Zealand. The heat from the eruptions is causing record temperatures around the world while the unusually warm oceans melt the ice shelves, glaciers and ice caps in the Arctic and Antarctic regions - as well as the Himalayans, the Andes, etc.

As record heat continues across the world, the unusually warm ocean waters are drilling river tunnels - 800 feet high - into the ice shelves, below the surface of the ocean. The ice shelves supporting massive glaciers - larger than the size of Pennsylvania - which weigh billions of tons. The glaciers are also being melted by volcanic heat from beneath.
Hundreds of glacial lakes, beneath Antarctica's ice sheet, are kept warm by the magma beneath the surface of the mountains.

Meanwhile the unusually warm ocean waters are rapidly evaporating - the atmospheric humidity is carried to nearby low-pressure systems where record rainfall is being dropped onto unsuspecting victims - soil saturation, landslides, sinkholes, train derailments and massive fissures are opening up in the Earth, devastating populations around the world.

The rapid melting of the glaciers around the world results in cold air being released - into the atmosphere - where wind currents carry the cold pockets of air to nearby low-pressure systems - the resulting hailstorms, record snowfall and record cold temperatures destroy homes, cars, crop fields and lives.

A worldwide famine is coming, including catastrophic displacement waves, killer quakes, record-breaking wildfires with 100 mph winds, record-breaking heatwaves, record-breaking rainfall, inundation, horrific destruction, the devastation of nuclear reactors along the coasts, lethal radiation poisoning, etc.

Prior to becoming a climate analyst, I studied ancient worldwide cataclysms until 1999, when a dramatic increase in alarming reports from glaciologists prompted me to turn my focus to monitoring climate change. I packed and left North America because the chances of surviving there are next to zero.

Click here to Reply or Forward

 

[Whirled Publishing]

Volcanic sea floor eruptions - around the world - have increased exponentially over the past several years - along with an alarming increase in volcanic activity above the surface of the oceans. Six volcanic islands emerged from the sea floor in under two years, for example, along with the pumice floating off the coast of New Zealand. The heat from the eruptions is causing record temperatures around the world while the unusually warm oceans melt the ice shelves, glaciers and ice caps in the Arctic and Antarctic regions - as well as the Himalayans, the Andes, etc.

As record heat continues across the world, the unusually warm ocean waters are drilling river tunnels - 800 feet high - into the ice shelves, below the surface of the ocean. The ice shelves supporting massive glaciers - larger than the size of Pennsylvania - which weigh billions of tons. The glaciers are also being melted by volcanic heat from beneath.
Hundreds of glacial lakes, beneath Antarctica's ice sheet, are kept warm by the magma beneath the surface of the mountains.

Meanwhile the unusually warm ocean waters are rapidly evaporating - the atmospheric humidity is carried to nearby low-pressure systems where record rainfall is being dropped onto unsuspecting victims - soil saturation, landslides, sinkholes, train derailments and massive fissures are opening up in the Earth, devastating populations around the world.

The rapid melting of the glaciers around the world results in cold air being released - into the atmosphere - where wind currents carry the cold pockets of air to nearby low-pressure systems - the resulting hailstorms, record snowfall and record cold temperatures destroy homes, cars, crop fields and lives.

A worldwide famine is coming, including catastrophic displacement waves, killer quakes, record-breaking wildfires with 100 mph winds, record-breaking heatwaves, record-breaking rainfall, inundation, horrific destruction, the devastation of nuclear reactors along the coasts, lethal radiation poisoning, etc.

Prior to becoming a climate analyst, I studied ancient worldwide cataclysms until 1999, when a dramatic increase in alarming reports from glaciologists prompted me to turn my focus to monitoring climate change. I packed and left North America because the chances of surviving there are next to zero.

Click here to Reply or Forward

 

[mamooth]

Volcanic sea floor eruptions - around the world - have increased exponentially over the past several years - along with an alarming increase in volcanic activity above the surface of the oceans.

No, there's no evidence for that. There's been a mild increase in surface vulcanism, but that has a slight cooling effect due to volcanic aerosols.

If undersea volcanoes were heating the oceans and melting ice, the local hotspots in the ocean would be clearly visible. They're not, hence undersea volcanoes aren't doing anything special. It would take something like a thousand-fold increase in undersea volcanoes to make the kind of heat you're postulating, and there's zero evidence of such a thing.

 

[Whirled Publishing]

Volcanic sea floor eruptions - around the world - have increased exponentially over the past several years - along with an alarming increase in volcanic activity above the surface of the oceans.

No, there's no evidence for that. There's been a mild increase in surface vulcanism, but that has a slight cooling effect due to volcanic aerosols.

If undersea volcanoes were heating the oceans and melting ice, the local hotspots in the ocean would be clearly visible. They're not, hence undersea volcanoes aren't doing anything special. It would take something like a thousand-fold increase in undersea volcanoes to make the kind of heat you're postulating, and there's zero evidence of such a thing.

Try doing the research - the local hot spots are visible on the anomaly maps - and the glaciologists reports are online.

 

[mamooth]

In that case, you should have no trouble pointing that data out to us. Please proceed.

 

[Whirled Publishing]

Google

http://polar.ncep.noaa.gov/sst/ophi/color_newdisp_anomaly_global_lat_lon_ophi0.png

The ice shelves are looking like Swiss cheese - with glaciers, the size of Pennsylvania resting on them - that's billions of tons ice precariously resting on melting cheese -

you do the math.

My calculations are rather alarming.

 

[Whirled Publishing]

I've been doing this research for decades -

that means you're not the expert here -

I am.

 

[Dot Com]

I've been doing this research for decades -

that means you're not the expert here -

I am.

as long as you keep supplying links, I have no argument w/ you

 

[Whirled Publishing]

I've been doing this research for decades -

that means you're not the expert here -

I am.

as long as you keep supplying links, I have no argument w/ you

Argue, insult, falsely accuse and complain all you want -

or do your own research -

the choice is yours.

 

[Old Rocks]

If you feel the request for a link to data supporting your hypothesis is an insult, you are obviously a fraud.

 

[mamooth]

Google

http://polar.ncep.noaa.gov/sst/ophi/color_newdisp_anomaly_global_lat_lon_ophi0.png

The ice shelves are looking like Swiss cheese - with glaciers, the size of Pennsylvania resting on them - that's billions of tons ice precariously resting on melting cheese -

you do the math.

My calculations are rather alarming.

Your link showed no hotspots at all along the coast of Antarctica.

Yet you claimed such hotspots were melting Antarctic ice.

Hence, your own data shows your theory is nonsense.