Inconvenient: Antarctica’s Ice Sheet May Be More Durable Than We Thought

On the same day that WaPo and other alarmist media outlets were wailing about a small loss in Antarctic ice balance, another study came out. This study found that the East Antarctic Ice Sheet has survived higher temperatures than we are experiencing now.

Mt. Erebus rising above the ice-covered continent. Credit: Ted Scambos & Rob Bauer, NSIDC

From PM:

Summary:

  • Scientists studied the Pliocene epoch, which happened a few million years ago.
  • Temperatures were a little warmer then, so the epoch could be a good preview of a warmer Earth.
  • They found Antarctic ice was more prevalent back then than we’d believed.

One of the biggest potential dangers of increasing climate change is sea level rise caused by the melting of the polar ice caps. As our planet heats up, large ice sheets in Greenland and Antarctica will melt, potentially triggering several feet of increased sea level rise. If the entire Antarctic ice sheet melts into the ocean, it could lead to dozens of feet of sea level rise, likely enough to wipe out entire cities.

Of course, it’s important to remember that ice sheets are complex and predicting how they will react is difficult—there’s a wide range of possibilities. Perhaps the best way for scientists to predict how ice sheets will behave in the future is by learning how they behaved in the past, so one group of scientists traveled to the East Antarctic Ice Sheet to learn its history.

Specifically, the researchers were interested in what happened to the ice sheet during the Pliocene epoch, the geologic period from about 5.4 million years ago to around 2.5 million. During the Pliocene, global temperatures were a few degrees warmer than they are today, which means this era is a good model for what our world might look like in a few decades, if climate change remains unchecked.

To determine just what happened to the ice sheet during this period, the researchers drilled deep into the rock beneath it. The scientists were looking for samples of certain isotopes, beryllium-10 and aluminum-26. These particular isotopes are created from the impact of cosmic rays from space. When these cosmic rays hit the atoms in the soil, they trigger atomic reactions that produce these isotopes.

The key fact here is that cosmic rays can’t penetrate ice. If there was ice over the ground during the Pliocene, the cosmic rays wouldn’t have reached the ground and these isotopes shouldn’t be present in the soil. But if the ice sheet melted significantly, the researchers would find higher levels of these isotopes.

“Based on this evidence from the Pliocene, today’s current carbon dioxide levels are not enough to destabilize the land-based ice on the Antarctic continent,” said study author Jeremy Shakun.

Full story here


The study: https://www.nature.com/articles/s41586-018-0155-6

Minimal East Antarctic Ice Sheet retreat onto land during the past eight million years

Abstract

The East Antarctic Ice Sheet (EAIS) is the largest potential contributor to sea-level rise. However, efforts to predict the future evolution of the EAIS are hindered by uncertainty in how it responded to past warm periods, for example, during the Pliocene epoch (5.3 to 2.6 million years ago), when atmospheric carbon dioxide concentrations were last higher than 400 parts per million. Geological evidence indicates that some marine-based portions of the EAIS and the West Antarctic Ice Sheet retreated during parts of the Pliocene1,2, but it remains unclear whether ice grounded above sea level also experienced retreat. This uncertainty persists because global sea-level estimates for the Pliocene have large uncertainties and cannot be used to rule out substantial terrestrial ice loss3, and also because direct geological evidence bearing on past ice retreat on land is lacking. Here we show that land-based sectors of the EAIS that drain into the Ross Sea have been stable throughout the past eight million years. We base this conclusion on the extremely low concentrations of cosmogenic 10Be and 26Al isotopes found in quartz sand extracted from a land-proximal marine sediment core. This sediment had been eroded from the continent, and its low levels of cosmogenic nuclides indicate that it experienced only minimal exposure to cosmic radiation, suggesting that the sediment source regions were covered in ice. These findings indicate that atmospheric warming during the past eight million years was insufficient to cause widespread or long-lasting meltback of the EAIS margin onto land. We suggest that variations in Antarctic ice volume in response to the range of global temperatures experienced over this period—up to 2–3 degrees Celsius above preindustrial temperatures4, corresponding to future scenarios involving carbon dioxide concentrations of between 400 and 500 parts per million—were instead driven mostly by the retreat of marine ice margins, in agreement with the latest models5,6.

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MarkW

Even if the worst case rate of sea level rise occurs, cities won’t be wiped out. They will just move a few miles inland. They will have several thousand years to adjust. Don’t start crying for coastal cities just yet.

Latitude

ohell Mark, they evacuated Detroit and Venezuela faster than that

Tom Halla

Another disaster scenario bites the dust?

This dust-biting is a major concern — it could unleash destructive climate forces. Requires major funding to study impacts…

Bryan A

Unfortunately the “Full Story Here” link takes you to a site where you have to pay a ransom to Not see Ads or you can’t view the content.
Just for curiosity sake, are both the amount of isotopes discovered and bore hole locations indicated in the remainder of the article?

Edit:
Apparently it is possible to view the article if one is tenacious enough.
Go to the link and read what you can, then back up and go in again and scroll down some before the screen freezes and the ransom message reappears. Repeat enough scrolling a little farther each time and after around 4 or 5 trips in, you will have read the entire article

I know virtually nothing about the ice-loss dynamics of the Antarctic.

How much ice actually “melts”? It’s pretty darn cold over most of the continent, so how does that work? And how could CO2 possibly be linked to processes that cause it?

I get the feeling that many people have a very childish view of “melting”, where Antarctica is concerned. Again, what’s the process or processes that remove ice from that continent? A reference would be helpful. Thanks.

J Mac

Sublimation, whereby solid H2O transitions directly to gas phase H2O, is a primary cause of snow and ice loss at low temperatures.

Has anyone studied the rate of sublimation in Antarctica,&how fast,under what conditions of wind &air flow ,water vapour saturation, other weather conditions etc.?

Felix

This should come as no surprise. The WAIS has also survived interglacials hotter than the Holocene, such as the Eemian, which also lasted longer than has our interglacial so far.

IMO it was probably more than two to three degrees C warmer than now in the Antarctic during the hottest part of the Pliocene. That range might apply in the mid-Pliocene warm interval (3.3-3.0 Ma), but during its early warmth (5.3-5.0 Ma), the epoch was likely balmier than that.

comment image?download

Mid-Pliocene reconstructed annual sea surface temperature anomaly:

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I like that version of Zachos… Much neater than mine!

Felix

Yours shows a line at which the ice sheet is thought to be stable, so is more useful, if the estimate be in the ball park.

Ionian, calabrian, gelasian, paicenzian, zanclean… So cool. Even though I spend most of my work days in the Plio-Pleistocene… I almost never get to use those words… 😉

Khwarizmi

Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian…so Jazzy!
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(edited for https imagery)

Felix

Funny guy. But the actual geological ages yet again falsify the CACA meme.

John

You mean it’s not all melted yet? I was sure from all the media hype there was nary an ice crystal left on the continent.

Percy Jackson

I would note that the last sentence of the abstract would appear to contradict the blog title. The
sentence reads:
“We suggest that variations in Antarctic ice volume in response to the range of global temperatures experienced over this period—up to 2–3 degrees Celsius above preindustrial temperatures4, corresponding to future scenarios involving carbon dioxide concentrations of between 400 and 500 parts per million—were instead driven mostly by the retreat of marine ice margins, in agreement with the latest models”

Which suggest that the correct title should be -“Experiments confirm model predictions about ice loss in Antarctia”

Not even wrong. Not even RCP8.5 melts the EAIS. The fact that much warmer temperatures in the past didn’t melt the EAIS confirms nothing in regard to models of the future.

Ocean heat transport in the Pliocene was substantially different than it has been in the Late Quaternary. This observation is irrelevant to models of the near future or recent past.

Tom O

Am I reading this abstract correctly? It “sounds” like they are say that there was insignificant melt back ON TO the continental land mass to register, thus there has been an ice sheet completely covering that part of the continent for millions of years. Or did I miss something? And if ice has been present all the way to the coast, with presumably only the ice shelf having melted, would the thickness have been less without melting the edges?

I’m just getting the feeling that “melting” caused by supposedly increasing air/ocean temperature has little to do with it. Rather, ice FLOW, gravity, friction, and the relationship between these things and snowfall, wind, and other processes — all changing and changing relationships over eons — rules the dynamics of ice loss.

It’s NOT like putting an ice cube in the oven, but that’s what alarmist reports seem to imply. It’s NOT that simple, I think.

It’s more like putting an ice cube in an oven filled with battery acid… /Sarc.

Khwarizmi

A tray of ice cubes can survive temperatures higher than you’ll find in your freezer!
comment image

►” We suggest that variations in Antarctic ice volume in response to the range of global temperatures…”

One of the most popular cognitive errors precipitates out from the universal grammar engine, in which abstractions take the place of a noun/object/thing, and are thus treated as if they were tangible physical entities. But a global average temperature is not a tangible physical entity – it’s a mathematical abstraction.

A globally-averaged temperature construct won’t melt any ice in Antarctica. Only regional temperatures can do that.

Felix

And regional temperatures show no warming for as long as records have been kept.

donb

Cosmic ray protons do penetrate ice, but only several meters worth.

Charles Nelson

In my days as an ad-man we used to have a media buying schedule called an ‘ice cream’ package whereby adverts for say, products like sun glasses, ice-cream or suntan lotion would only play out if the temperature went above a certain point for a certain time.
Has anyone else noticed that these ‘melting ice sheet’ stories are always punted out during the warmer days of the year?
It’s much easier to sell global warming on a sweltering day…right?

Renee

Do you know sea ice melt is seasonal? Longer term trends suggest Antarctic sea ice is actually growing whereas Arctic sea ice is declining. The most recent years for Antarctic sea ice shows higher standard deviation from the trend line in both seasonal high and low sea ice. Graph from climateforyou.
https://imgur.com/a/xUUwd

Fredar

I thought Mann said that there should be no debate. The science is settled. Why are these people wasting their time then?

Alan Tomalty

I am astonished. Everybody missed the significance of the last sentence in the conclusion of this report.

“We suggest that variations in Antarctic ice volume in response to the range of global temperatures experienced over this period—up to 2–3 degrees Celsius above preindustrial temperatures4, corresponding to future scenarios involving carbon dioxide concentrations of between 400 and 500 parts per million—were instead driven mostly by the retreat of marine ice margins, in agreement with the latest models.”

What that last sentence says is that their own models are predicting no significant non – natural (CO2 by man ) melting of Antarctica due to a doubling of CO2 in the atmosphere from 280 to 560. What this means is their very own models are not predicting any disastrous effects from Antarctica melting. Don’t forget the 3C is the IPCC average sensitivity to a doubling of CO2. That sensitivity average hasnt changed in 30 years . If their very own models (over 125 worldwide) are saying that the cause is natural for Antarctica why wouldnt the cause be natural for Greenland as well? They actually said “driven mostly by the retreat of marine ice margins”. Well what that means is; they dont know the cause but they are saying that CO2 is a minor player. If CO2 is a minor player in ice sheet melting for a doubling of CO2 then it is a minor player in everything for CO2 doubling. Don’t forget that the models cannot tell them what % is by man and what % is natural.

That is the reason that the IPCC has always refused to put a number on it. Since the models can’t split out the effects of man vs natural, when they ran the simulations both forward and backward ; the forward simulation effects of the future of the ice melting must have ended up to be exactly the effects of the models running backward as well. Since the variables data are the same for both simulations the same results were obtained. That in itself is remarkable given the models propensity to become chaotic when running simulations.

They in effect have had to fine tune out these chaotic simulations by flattening out the parameterizations for very long term predictions. For the researchers to have admitted this; is astonishing . What this means is that there is no disaster syndrome. They are in effect admitting that RCP8.5 is impossible because RCP8.5 is a business as usual scenario with emissions continuing to rise. I am making the statement that in this case of Antarctica melting there cant be any CO2 effect if the same effects happened with the same input variables with the only difference being CO2 levels. If there isnt any effects on CO2 doubling there cant be any effects on CO2 quadrupling or more. RCP8.5 says that 5C increase happens only after 2081 to 2100.
Even the IPCC admits that 3C difference in the RCP8.5 doesnt kick in until after 2065 ; 47 years from now . If the doubling of CO2 doesnt produce any greenhouse effect on ice melting then all bets are off. The AGW house of cards falls flat on its face. Dont forget that Dr. Pierre Robitaille has proved that CAGW is impossible because of the fact that CO2 and H2O decrease emissions of back radiation with increase in temperature. Dr Michael Modest has also stated that in his bible of Radiative Heat Transfer.

I am sure the researchers will be getting a nasty call from both Gavin Schmidt and Michael Mann.

1) Since melting of the Arctic would only add 20mm and melting of all 200000 glaciers would add 400mm and if you take Greenland and Antarctica out of the picture then what do we have to worry about?

2)A measly 3C for a doubling of CO2 to 560PPM . We are way below the target of 3C anyway based on the past 70 years and it looks like it will take another 70 years to get to 560ppm. Is anyone in the world going to die of heat prostration from an increase of 3C especially since we got 70 years to warn them ? What else is there to worry about?
3) Since CO2 is NOT responsible for extreme weather events. We know this since every government agency in the world that tracks these stats shows no increase in extreme weather events. Come to think of it Trump should protect the American extreme weather events databases from possible tampering by NASA, NOAA, and NCAR. I am astonished that I am living in a world that I would ever have to make the previous suggestion.

4) So the only other possible detriment to CO2 is that study that found some decreased levels of vitamins from crops that were grown with doubled CO2 levels. Well the amounts were small and there wont be malnutrition caused by that.

SO I FEEL LIKE ALFRED E. NEWMAN (fictional character) with his famous saying. “Whatttttt me worry?

Epilog: I would be happy except my PM Trudeau in Canada wants to bring in around $74 to $112 billion extra greenhouse gas taxes over next 5 years. All of that money will have been collected to decrease the world’s average temperature by 5/1000 of a degree C and that will only be 82 years from now. We in Canada unfortunately are living in the World of Oz and desperately need Toto to learn how to pull back the curtain.

Graham

Thanks for this.

I was struck by the lovely picture and thought it would be worth sharing this little, localised disaster with your audience – totally off topic, but worth a moment or two of commemoration, if you please.

“On 28 November 1979, the fourteenth flight of TE-901, a McDonnell Douglas DC-10-30, registration ZK-NZP, flew into Mount Erebus on Ross Island, Antarctica, killing all 237 passengers and 20 crew on board. The accident became known as the Mount Erebus disaster”

https://en.wikipedia.org/wiki/Air_New_Zealand_Flight_901