Half of Antarctic ice shelves could collapse in a flash, thanks to warming

Feb 19, 2020
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The climate has warmed in the past. From ~1880 to ~1940. Did these Antarctic ice shelves start to collapse back then? After all the global climate has warmed less than one degree C overall. Or is this just a model of what might happen?
 
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Jul 27, 2020
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After all the global climate has warmed less than one degree C overall. Or is this just a model of what might happen?
It appears that deep water up-welling is driving most of the melting of basal Antarctic ice. The ocean temperature there is much warmer than expected. Here is something that sounds rather alarming from the "Intro" (in the below article) :

"The Antarctic Peninsula has been one of the most rapidly warming regions of the world during the twentieth century where ~75% of the ice shelves have already retreated over the past 50 years."


Here is a link to that :

"Ocean temperature impact on ice shelf extent in the eastern Antarctic Peninsula" (18 January 2019)


While the temperature variations do not seem extreme, the effects on the ice sure seems apparent.
 
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"The Antarctic Peninsula has been one of the most rapidly warming regions of the world during the twentieth century." An interesting quote. Most of the recent climate concern has been about so-called Arctic amplification...the fastest warming part of the globe.

My quesation was this: The climate has warmed in the past. From ~1880 to ~1940. Did these Antarctic ice shelves start to collapse back then? Or at any time in the past?
 
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My quesation was this: The climate has warmed in the past. From ~1880 to ~1940. Did these Antarctic ice shelves start to collapse back then? Or at any time in the past?
Your persistence has paid off. And it has provided me with information not previously known. Below is a quote from my favorite source of information (that Nature article was found on one of their sites. Wiki is an excellent source for references to original papers.)

The quote is from Wiki on "Retreat of glaciers since 1850*". Just the time period you are asking about, and no doubt for a good reason. You clearly know a lot about this sort of thing.

"The Little Ice Age was a period from about 1550 to 1850 when the world experienced relatively cooler temperatures compared to the time before and after. Subsequently, until about 1940, glaciers around the world retreated as the climate warmed substantially. Glacial retreat slowed and even reversed temporarily, in many cases, between 1950 and 1980 as global temperatures cooled slightly.[3] Since 1980, a significant global warming has led to glacier retreat becoming increasingly rapid and ubiquitous, so much so that some glaciers have disappeared altogether, and the existence of many of the remaining glaciers is threatened. In locations such as the Andes of South America and Himalayas in Asia, the demise of glaciers in these regions has the potential to affect water supplies in those areas."

end quote

Clearly the growth and melting of glaciers has been significant in the last few centuries or so. No doubt you were aware of this. But the trend now appears to be melting beyond the cooling period accumulations, and now we are going into a new phase of melting. Or so the data seem to indicate.

If you can tolerate all the data, this is very revealing :

* https://en.wikipedia.org/wiki/Retreat_of_glaciers_since_1850
 
Aug 2, 2020
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90 % of the sea ice shelves breaks off yearly never a boost to sea level. Think on it put some ice in a glass with some water mark the level. When the ice melts does the water in the glass rise, does it over flow. Displacement, it stays the same. Give me something tangible to believe in on man made climate change, other than we need a tax administered by the UN who backs this climate change hocus pocus
 
Apr 30, 2020
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Tbe temperature on Earth has consistently but slowly varied from one extreme to the other about every 40,000 years and nature (living things) has accommodated the change by moving in the case of herbivores alternately between the equator and the arctic circle. The big difference now is that our use of fossil fuels has accelerated the change so it is happening much faster than we can cope with. Climate change deniers frequently use the fact that there have always been these swings, to spread misunderstanding and a sense of impotence. Unless we very quickly wake up and adopt a means of mitigating the chaos and disaster awaiting us, it will be too late. We have desploiled a wonderland with our greed and ignorance. Politicians don't help. Read my paper under climate change in live science. It offers an economically sound means to slow the rate of temperature increase down NOW not when it's too late!
Whitefeather
 
Mar 28, 2020
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The article says, "These floating ice sheets ring Antarctica's glaciers and prevent them from sliding into the ocean."

That's gibberish:
  • Ice sheets don't float.
  • Antarctica's glaciers would not "slide into the ocean" if the adjacent floating ice shelves floated away.

Most readers probably:
  1. Do not know the difference between "ice shelves" and "ice sheets." In fact, neither does the science journalist who wrote this article, obviously, since she used the terms interchangeably. Ice shelves are floating ice, and ice sheets are the vast masses of grounded ice, which contain 70% of the Earth's fresh water.

  2. Don't know that ice shelves represent a minuscule fraction of Antarctic ice.

  3. Don't realize that melting or disintegrating ice shelves don't affect sea-level.

  4. Don't know that ice shelves are constantly breaking away at the outside edges, in pieces large and small, and they are constantly being replenished with ice flowing downhill from upstream glaciers and ice sheets.

  5. Don't know that most of the ice in the ice shelves originated as part of the ice sheets and glaciers, which flowed downhill into the ocean. (Most of the rest is snowfall accumulation.)

  6. Don't know that Antarctica averages more than 40° below zero, so most of it is in no danger of melting.

  7. Don't realize that the article's claim that "ice shelves confined to bays and gulfs create a physical barrier that the slow-moving glaciers butt up against," and thereby affect ice flow rates, describes an extremely minor and transient effect.
Point #7 deserves a bit of elaboration.

When I say "extremely minor," what do I mean? Well, here's a quote, from a paper about it:
"Loss of buttressing offsetting half of the tendency for ice‐stream/ice‐shelf spreading for an ice stream similar to Pine Island Glacier, West Antarctica is modeled to contribute at least 1 mm of sea‐level rise over a few decades." https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004GL022024
Yes, you read that correctly: "at least 1 mm of sea-level rise over a few decades." Batten the hatches, we're all gonna drown!

It is also transient, because when ice flow rates from glaciers and ice sheets increase, the influx of ice tends to cause the downstream floating ice sheets to grow again: a negative (stabilizing) feedback mechanism.

Greenland is similar, but not as cold. Here's an article about Greenland's largest glacier, which feeds a downstream ice shelf that had almost completely disappeared... but is now "growing back."
https://climate.nasa.gov/news/2852/cold-water-currently-slowing-fastest-greenland-glacier/

Here's the effect that global warming is having on sea-level:
https://sealevel.info/1612340_Honolulu_vs_CO2_thru_2020-03_annot1.png
 
Feb 19, 2020
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A response to Chem721. It is important to distinguish between glacial ice and polar ice shelves as Mogoso pointed out. The back and forth growth and retreat of glaciers is well known. My question was about the polar ice caps, not glaciers.

A response to Whitefeather is that his acceleration of change since pre-industrial time is just a trivial 0.75°C as of 2019. It was 0.83°C in 2016. There is no meaningful way to mitigate that trivial amount of chaos by moving CO2 around...lowering emissions does not lower the CO2 we have already added.
 
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Apr 30, 2020
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The point is that the 'trivial' amount of warning you refer to is enormous when applied to the oceans. They have acted like a 'heat sink'. If we had't had them we would have fried to death ages ago.
The amount of carbon and other trash fuels we have consumed has also meant that we have polluted the atmosphere with gases that hinder the reflection of heat from the Earth. Also, as the ice caps melt they lose their reflective ability so we are now astride an exponential effect. It's accelerating rapidly. Another exponential process is the carbon now escaping from frozen tundra and ice caps as they warm up.
As long as we cease using hydrocarbons as fuels, we can allow nature to store existing CO2 for us as it's done for millions of years. That's if we stop destroying the Amazon of course.
I do wonder how many catastrophes need to occur before people realise that global warming is a far greater threat than Covid 19 !!!!!!!!!
Whitefeather
 
Apr 30, 2020
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90 % of the sea ice shelves breaks off yearly never a boost to sea level. Think on it put some ice in a glass with some water mark the level. When the ice melts does the water in the glass rise, does it over flow. Displacement, it stays the same. Give me something tangible to believe in on man made climate change, other than we need a tax administered by the UN who backs this climate change hocus pocus
 
Apr 30, 2020
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You seem to forget that water (ice) at 0 degrees Centigrade expands as it warms up to 4 degrees centigrade. It's why pipes burst in the winter time! So don't tell me that polar ice melting won't raise sea levels.
 
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Whitefeather... "As long as we cease using hydrocarbons as fuels, we can allow nature to store existing CO2 for us." Yes, and we will need it in the future when it becomes obvious that renewables don't lower CO2, they add to it. But the Covid-19 lockdown has shown very clearly that any rapid lowering of carbon fuel emissions will create the social and economic havoc we are still incurring. We can't expect a different result going forward. The only way to lower atmospheric CO2 on a permanent basis is industrial CO2 capture and geological storage. Anyone doing the math on that will soon see it cannot work. Nature did it but it took millions of years.
 
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Clearly you have no idea of renewable energy and how it works. As for carbon capture on a huge scale, you have to be joking. Far more sensible to turn North Africa and some other desert areas into self-sustaining forests. I'll give you some maths to dwell on. An area the size of Wales filled with solar panels would supply the entire energy requirements of the world. Look it up.
 
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Whitefeather? Solar panel and wind turbine "farms" do NOT lower any CO2. Renewable biofuel farms create ethanol that is immediately burned when mixed with 90% fossil fuel. Forests are not self-sustaining as wildfires have always illustrated, even now. Planting millions of new forests of trees is in conflict with land for human agriculture, land for biofuels, land for solar panel farms and land for people to live on. And they would have to be protected as well.

As for the math... To capture and permanently remove and bury just one part-per-million of oxidized carbon (at the source or directly from the air) means the burial of 7.8 Gt, or 7,800 million metric tons. At today's burial rates that ONE ppm would take about 200 years. That's the math. The time it might take is negotiable, the amount is not. And that, of course, is just ONE ppm when way many more would be needed to affect the Earth's climate.
 
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A response to Chem721. It is important to distinguish between glacial ice and polar ice shelves as Mogoso pointed out. The back and forth growth and retreat of glaciers is well known. My question was about the polar ice caps, not glaciers.
You surely know this but to review:

Technically there is only one ice cap, and that is the North Polar Ice Cap, soon to be known year 'round as just the Arctic Ocean. Antarctica is a continent, a land mass that is largely covered in ice that extend into the southern oceans as shelves.

Melting of the north polar ice cap seems a no brainer. The water is getting warmer, and the albedo is decreasing. That is why it is disappearing so fast. It is not, of course, a glacier. Last time I read about this, 40% had melted in the summer of a recent year.

The south pole is much different and clearly more complex. Some areas of the continent are significantly colder than others, and are melting at variable rates. But since ice is melting inland and at the shelves, beyond anything seen before the industrial revolution, it seems difficult to distinguish the two - melting land ice or shelves. Clearly the mechanism is different, but the global impact is the same - increasing sea levels.

Clearly CO2 remediation is the ideal solution to at least that aspect of the problem. But how is capture and storage implemented. I have read about deep ocean injection, where liquid CO2 sinks into the bottom and is apparently sequestered. What more can you tell me about CO2 remediation?
 
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Chem721... "Clearly CO2 remediation is the ideal solution to at least that aspect of the problem. But how is capture and storage implemented. I have read about deep ocean injection, where liquid CO2 sinks into the bottom and is apparently sequestered. What more can you tell me about CO2 remediation?"

I just tried to explain that quantitatively to Whitefeather. There are many suggestions as to how to "remediate" CO2. None of them is meaningful at the levels of CO2 required to make a difference to the climate, irrespective of their total costs. The weight of oxidized carbon is simply too much for humans to attempt in the limited time involved.

Repeating... "To capture and permanently remove and bury just one part-per-million of oxidized carbon (at the source or directly from the air) means the safe burial of 7.8 Gt, or 7,800 million metric tons. At today's burial rates that ONE ppm would take about 200 years."

Liquid CO2 under pressure is problematic. Dry ice is something one can weigh. Of Course, there is no way to keep dry ice from subliming with the captured CO2 back into the atmosphere. Keeping captured CO2 under pressure in the Earth is bad enough. But, the technology does have value. It is being used for secondary oil recovery. Probably to the chagrin of the Green deal promotors.
 
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"To capture and permanently remove and bury just one part-per-million of oxidized carbon (at the source or directly from the air) means the safe burial of 7.8 Gt, or 7,800 million metric tons. At today's burial rates that ONE ppm would take about 200 years."
Broadlands, you have a distinct advantage over me from my lack of knowledge of existing technologies and capabilities. So it is my challenge to see if you are aware of other evaluations that might lead to an actual reduction in CO2, or at least neutrality.

Looking up the latest on carbon dioxide removal (CDR), I found an interesting link to a NASEM* report which suggests that a combination of mechanisms can currently be used to eliminate 20% (ca. 10 gigatons of carbon dioxide) of current world output, both on a yearly basis. While this does nothing to decrease existing levels, current technologies are focused on limiting the increase. It seems likely that more advanced technologies, combined with a reduction in CO2 output, might eventually lead to a reduction. Science advances technology. And as you know, this is not a static issue.

* " Negative Emissions Technologies and Reliable Sequestration: A Research Agenda" (October, 2018)


Unfortunately the above link only takes you to a brief summary, and allows you to buy a costly book. Are you familiar with this report? A summary (see below link**) extracts a claim from the above report that states "approaches such as direct air capture and carbon mineralization have nearly unlimited CO2 removal capacity."

It appears that a substantial amount of reduction using a variety of techniques, from direct capture (at point sources) to "carbon farms" is possible. There is certainly a great deal of research done on CDR, and its large scale use seems likely that a net neutral or even decline in CO2 might eventually be achieved. But this might be the optimist in me, always assuming that science is our one and only savior.

Do you believe that these efforts are doomed to failure due to a cost evaluation, and/or technical hurdles which cannot be overcome? Many are certainly inclined to give NASEM's proposals room for serious consideration.

** https://bipartisanpolicy.org/wp-content/uploads/2019/06/Carbon-Removal-Comparing-Historical-Investments-with-the-National-Academies-Recommendations.pdf
 
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Chem721. The amount of CO2 required to affect the Earth's climate is not negotiable, wishful thinking or other evaluations notwithstanding. The numbers are clear and scaling up remediations to make them viable is not an option in the time allotted... by 2050..2080?

The Global CCS Institute has been meeting this past month: "Collectively, the 19 large-scale CCS facilities in operation have the capacity to capture and permanently store 39 million tonnes of CO2 every year. The total capture capacity of all 51 large-scale facilities in the pipeline is 98 million tonnes of CO2 per year.”

Simple arithmetic shows us that to store 39 million tons per year would take 200 years to remove that ONE ppm. Divide 7,800 by 39. Even with facilities in the pip[eline, that is doomed to failure by any measure. Costs per-ton stored would be astronomical. Some (NASA’s James Hansen, Bill McKibben) have urged us to go back to 350 ppm to be safe. That is now 65 ppm or almost 500 billion tons. Totally impossible.

I have written to the National Academies and they don't reply other than to recommend their own publications that don't address the quantitative issues. The Global CCS Institute leadership is not inclined to listen, even though they must know what the numbers tell them.
 
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Totally impossible.

If you are correct, some major people in this story are playing fast and loose with the data, and painting a very rosy picture, one that is certainly disconnected from reality.

It would seem that revisions in world atlases will have to made routinely to account for the disappearance of numerous island countries at low sea level, and the continuously changing topography of the world's "shorelines".
 
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Yes, most people are quite unaware of how much oxidized carbon actually weighs. All they have to do is pick up a large block of dry ice before it sublimates and visualize the atmospheric amounts needed. There is no imminent danger of island countries or shorelines being inundated that are not otherwise subsiding. But some serious redirection of funding should go toward innovative infrastructure adaptations that will be necessary no matter what the climate decides to do or does do. After all, the needs of those in the high latitudes and altitudes are quite different from those at sea level or close to the Equator.
 
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There is no imminent danger of island countries or shorelines being inundated that are not otherwise subsiding.

Please don't take this as being argumentative. Corrections you have made are noted. I have found nothing to fault with any of your commentary, except it would appear that some things are already being impacted by rising sea levels.

In particular is seawater intrusion into low lying areas killing off large areas of forest, as in this report (1) about the east coast of the U.S., but is reported occurring around the world.

Also, some low lying coastal areas and islands are rapidly becoming uninhabitable due to higher high tides (King Tides) which now flood previously dry land. This is also occurring in south New Jersey coastal areas.

And then there are the Marshall islands (2).

They are constantly being harassed by flooding seas. One of the reasons is taken from (2) :

"Changing global trade winds have raised sea levels in the South Pacific about a foot over the past 30 years, faster than elsewhere. Scientists are studying whether those changing trade winds have anything to do with climate change."

Many of these islands are rapidly becoming uninhabitable, with continuous flooding disrupting homes, sewage, etc.. It is certain many other small, low lying island nations are experiencing similar problems.

When I first quizzed you on the carbon remediation, was hoping we could pull something off. But the numbers you present are devastating in their magnitude. Unless someone comes up with a unique and brilliant solution for carbon remediation, this is going to be nasty. In truth, it was always my suspicion that it is too late to do anything about it. Guess I was hoping you had some ideas about rabbits pulled out of hats.

Sadly, the evidence does indicate the problems have already begun.


1. https://www.nytimes.com/interactive/2019/10/08/climate/ghost-forests.html

2. https://www.nytimes.com/interactive/2015/12/02/world/The-Marshall-Islands-Are-Disappearing.html
 
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Chem741. Yes some evidence has appeared,. But remember the same evidence appeared in the past...long before the human added CO2 could have been the problem. The important point people now keep missing (avoiding) is that CO2 mitigation is not the answer. Cannot be the answer. There is no silver bullet, no rabbits pulled out of some scientists or politician's hat. Even while Some Pacific atolls are actually rising. There are no human inhabited places that have been permanently inundated, even after a 45% increase in CO2. But it doesn't matter if we cannot do anything meaningful about it by CO2 mitigation. That is what is sad. We must ADAPT! Stop thinking that all we need is resolve and the will to do it. The numbers are clear. Do the math. It can't be done. ADAPT...while slowly reducing our needs for carbon as we use those renewables in need of carbon backups when the Sun stops shining and the wind stops blowing and batteries stop recharging. It is already happening. Likely o get worse.
Escaping hurricanes in PV vehicles? Bad enough with ICE vehicles out of gas...because of climate change??
 
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Nowhere near as costly as mitigation plus adaptation. The alternative? Phase out fossil fuels, phase in renewables with emphasis on adaptation instead of trying to eliminate carbon to zero and then to Net-zero. The unintended consequences and collateral damages of zero carbon are many. Imagine a world with no concrete or Portland cement and no asphalt on which to build and then drive PV vehicles, or store CO2 under pressure, in order to save the planet from a theoretical model-driven catastrophic future. A future unlikely to be that bad if the lessons from the geological past are any indication.
 

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