Antarctic sea ice today from the University of Bremen, on track for a new record high this year:
From Georgia Tech’s Judith Curry:
“Our finding raises some interesting possibilities about what we might see in the future. We may see, on a time scale of decades, a switch in the Antarctic, where the sea ice extent begins to decrease…”
Resolving the paradox of the Antarctic sea ice
While Arctic sea ice has been diminishing in recent decades, the Antarctic sea ice extent has been increasing slightly. Researchers from the Georgia Institute of Technology provide an explanation for the seeming paradox of increasing Antarctic sea ice in a warming climate. The paper appears in the Early Edition of the Proceedings of the National Academy of Science the week of August 16, 2010.
“We wanted to understand this apparent paradox so that we can better understand what might happen to the Antarctic sea ice in the coming century with increased greenhouse warming,” said Jiping Liu, a research scientist in Georgia Tech’s School of Earth and Atmospheric Sciences.
For the last half of the 20th Century, as the atmosphere warmed, the hydrological cycle accelerated and there was more precipitation in the Southern Ocean surrounding Antarctica. This increased precipitation, mostly in the form of snow, stabilized the upper ocean and insulated it from the ocean heat below. This insulating effect reduced the amount of melting occurring below the sea ice. In addition, snow has a tendency to reflect atmospheric heat away from the sea ice, which reduced melting from above.
However, the climate models predict an accelerated warming exceeding natural variability with increased loading of greenhouse gases in the 21st century. This will likely result in the sea ice melting at a faster rate from both above and below. Here’s how it works. Increased warming of the atmosphere is expected to heat the upper ocean, which will increase the melting of the sea ice from below. In addition, increased warming will also result in a reduced level of snowfall, but more rain. Because rain doesn’t reflect heat back the way snow does, this will enhance the melting of the Antarctic sea ice from above.
“Our finding raises some interesting possibilities about what we might see in the future. We may see, on a time scale of decades, a switch in the Antarctic, where the sea ice extent begins to decrease,” said Judith A. Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech.
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The propensity to speculate about the future and to see “signs” is endemic in science today. Increasingly, modern science is no longer distinguishable from voodoo or witchcraft. I suspect Judith and her cronies have a cauldron:
“Wool of bat and tongue of dog, Adder’s fork and blind-worm’s sting, Lizard’s leg and owlet’s wing, For a charm of powerful trouble, Like a hell-broth boil and bubble. ALL. Double, double toil and trouble; Fire burn and cauldron bubble.”
We skeptics can have oracles too – for McIntyre said that:
“Mann shall never vanquish’d be until
Great Burn’em wood to high Hokey shtick
Shall come against him.”
These folks at Georgia have no clue how Climate works. As the globe warms the precipitable potential arriving to the poles decreases; the perturbations that turn that potential into precipitation become weaker. And as usual, no mention of the upward migration of the rain/snow threshold in a warming scenario.
The media and these unscrupulous “scientists” try to deceive the public day by day with things like this. When will it all end?
“We wanted to understand this apparent paradox so that we can better understand what might happen to the Antarctic sea ice in the coming century with increased greenhouse warming,” said Jiping Liu, a research scientist in Georgia Tech’s School of Earth and Atmospheric Sciences.”
And here I thought that you made observations and then formulated a theory based on the observations….
Increased warming of the atmosphere is expected to heat the upper ocean
Of course, this mode of heating will totally overwhelm direct solar heating. One might call this the reverse conduction mode of heating.
Happy to see that others have found similar incongruities.
Judith is waving her arms about her so much she’s actually taken flight.
The “CO2 is a pollutant” scientists remind me a lot of the “fat and cholesterol are killing you” scientists. Both take substances essential to life and demonize them to the point where the substances’ irreparable harm reduced to an assumption. Odd that these very same people believe themselves to be the protectors of the environment.
It is pretty obvious that these people have no practical experience whatsoever of cold climates or sea ice. Increasing snowfall leading to more sea-ice! Utterly absurd. Sea Ice freezes mostly from above, since water can’t get colder than about -1.7 centigrade even when salt. Snow is an excellent insulator and prevents thick ice from forming. It is always chancy to walk on ice covered by deep snow, because it may be paper-thin even after a prolonged cold spell.
The only time when increased precipitation can lead to thicker ice is in arctic summer when fresh water percolating through the ice will freeze on contact with the subzero saltwater and “underplate” the ice.
We may see, on a time scale of decades, a switch in the Antarctic, where the sea ice extent begins to decrease,” said Judith A. Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech.
This is as useful as the following forecast: “In the next 12 months we may see some clouds, but also some sunshine, and some rain, as well as some snow. It will be windy sometimes, too. But not all the time. I think.”
Are these people scientists?
Perhaps not entirely OT: Cryosphere’s sea-ice curve for Antarctica just went off the chart:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
mosomoso says August 16, 2010 at 9:40 pm
…that the woman is shifty!
It may be that Judith Curry just doesn’t buy this BS any more, but cannot say that without losing her job. She is already on warning, I expect, given the reaction of the Team to her previous attempts at reason.
West Antartica is part of the ring of fire.
Has a study been done to see the effect elevated seabed temperatures have on seawater temps and corresponding ice shelf effects.
How about gravity effects do to shifting Magma or the possible sinking of the seabed do to overburden of the ice accumulation.
“Our finding raises some interesting possibilities about what we might see in the future. ”
Are “findings” here that of intrepid explorers on the sea ice or the GCMs and their intractable CO2 viruses.
Judith
I just read Zhang’s paper from 2004 where he basically said the same thing. Is there any real data to support this thesis? What are the long term salinity measurements in the Antarctic, have they confirmed the stratification?
Looking at how the seas act in the Circumpolar area I have a hard time believing that this extreme stratification exists.
Had another thought on this one as I have been reading the papers. If this model based thesis is true and the stratification of salinity and the temperatures is the case, then we should be seeing a shift forward in the inflection point where the maximum melting occurs during the Antarctic ice melt season. Has this shift been seen? Just looking at the NSIDC graphs I don’t see it.
The reasoning is this. Especially today with the much greater volume of Antarctic ice, the stratification effect should be amplified during the initial part of the melt season. This would tend to decrease local salinity and since mixing is reduced vertically, this should result in a retardation of the rate of melt. Therefore a shift of the inflection point of when the maximum melt period is should occur.
Dear Dr. Curry…
Specifically, I don’t agree with your following argument:
However, the climate models predict an accelerated warming exceeding natural variability with increased loading of greenhouse gases in the 21st century.
Most models are based on incorrect data that attributes physical properties to “greenhouse” gases that they don’t have. For example, the absorptivity of the carbon dioxide, its total effective emissivity, its capability to intercept IR photons, its incapability to retain photons for periods longer than 15 – 25 as (1 attosecond = 1 x 10^-18 s), etc. Still on Venus, where the carbon dioxide mass fraction is 950000 ppmV, the carbon dioxide is not a good interceptor of photons due to the high temperature of the Venusian surface.
My question is, have you considered the geological phases of sea level and ice extent and the sequence of icehouse-warmhouse periods? I have the impression that those natural hasty shifts have been absolutely dismissed on models.
I do wish people would stop playing with computer models and calling it science.
AGW experts should argue that due to global warming, you know with the increased snow storms and record-breaking cold air outbreaks, that Arctic sea ice will increase in a warming environment…because that’s what we’re observing the past few years.
As soon as I see ‘might’ ‘may’ ‘maybe’ ‘could’, on the same page as models…
…….I start thinking about what to have for lunch
Marvellous – so CO2 causes both warming and cooling
Precisely!
The important distinction is on a regional basis.
What this means is that the global energy imbalance (if any)
is actually too high because the cooling effect of additional CO2
as occurs in Greenland, Antarctica, and high clouds.
The forcing number ( from the the log formula for CO2 and other GHGs )
is from one-d models which don’t include things like the cold surface of
Antarctica or any clouds. This is applied to the GCMs.
So that amount of GHG forcing is baked in the cake as an assumption
because the 1d models lack fidelity to the real world where additional
CO2 cools the Earth/Atm system under some cases.
Empirical scientists would like to know.
BTW: Not missing a tropospheric hot spot are you, or some Long Wave radiation as measured by the ERBE and CERES satellites, and how are those model projections holding up vs the actual temperature record? Hmmmm?
In all seriousness – how on earth do I distinguish your all warming all cooling CO2 theory as an actual falsifiable scientific theory and not quakery?
As I said – please rule some phenomena out – then we can measure it and see how your theory stacks up. – anything else is nonsense.
Judith Curry says:
August 17, 2010 at 6:26 am
Thank you for your response, Judith.
I wonder whether I made myself clear enough.
You conceded that a change in the speed of the hydrological cycle was capable of ‘insulating’ the Antarctic surface waters against the effect of AGW.
You must accept that if such an outcome can occur regionally it can also occur globally. You report a greater increase in precipitation than the increase in evaporation which suggests there is a link to an accelerated hydrological cycle outside the geographical area of study.
Thus none of your speculations in your paper can be valid if they rely on an AGW effect from more CO2. You confirmed that a regional CO2 effect can be cancelled out by a change in the speed of the hydrological cycle. Do you not realise where that must lead you ?
Furthermore you seem to accept that the models are inadequate on the issue yet seem determined to speculate on the basis of modelled outcomes.
Why do people here need the hair dryer bathtub analogy to understand what they should have already comprehended from high school physics? I don’t think most do need that, but here goes:
Water has one of the highest heat capacities of all known substances. Ice has an amazing heat capacity coupled with one of the largest latent heats of crystallization of known substances. These facts mean that it takes a whole lot of energy to do a little movement.
Water and ice are up at the top of the most efficient heat sinks in the universe. Earth’s surface is 70% of this stuff to depths of miles. Amazing stuff.
The temperature of the tropopause is 220K everywhere e.g. over the poles and over the equator or tropics.
No. http://www.meteo.psu.edu/~nese/3_12_Tropopause_Temperature.bmp
The thing that is varying is not the CO2 radiation but the radiation at other wavelengths relative to CO2. This radiation will come from the surface and lower troposphere. Clouds will reduce this radiation and so will a very cold surface with high albedo (as in the case of the poles relative to the tropics). In both these cases the radiation characteristic of CO2 will be greater than the background so will appear as a “bump”. There is nothing surprising about this.
Right. Under these circumstances, additional CO2 means more energy is leaving
earth than would otherwise occur.
Incidentally the statement:
“In the Antarctic ( bottom plot ), CO2 presents as a ‘bump’ up in emissions.
CO2 emits to space from the stratosphere at a higher temp than the cold Antarctic
surface, thus INCREASING the loss to space – cooling the Antarctic”
is just wrong.
The tropospause is always colder than the surface although in many places the mountains reach close to the tropopause (which is only at about 8Km at the poles) and so the temperatures will come very close. CO2 is cooling the Antarctic but no more than at any other lattitude.
No. During the Antarctic winter (limited to be sure),
surface temperatures can in fact be lower than the temperatures
at the level of CO2 emission as the spectrum indicates.
Look again at the emission spectra.
http://acmg.seas.harvard.edu/people/faculty/djj/book/bookhwk7-1.gif
Over the Sahara, the dip means a reduction in the energy lost to space due to CO2.
Over the Antarctic, the bump means an increase in the energy lost to space due to CO2.
Increasing the amount of CO2 should increase the width of the dip and the bump
due to band broadening.
The issue that these charts raise is one that I have raised before. The concept of global warming depends on reducing the amount of energy radiated into space by CO2. These charts clearly show that this radiation is being emitted from the coldest layer in the atmosphere. The only way that radiation can be reduced further is for the temperature of this layer to reduce. I am unaware of any good evidence that this is happening.
I believe the average CO2 emissions in the middle of the band are from higher
than the tropopause, from within the stratosphere.
And there is evidence in the RAOB data and MSU data of a decades long
cooling trend in strat temperatures as the GCMs do successfully model.
But one will notice that much of the trend comes from the resolution of
the El Chichon and Pinatubo eruptions – temperatures rose after the
eruption because of increased absorption by the dust/SO2.
In both cases, after the dust/SO2 settled, temperatures fell to levels much lower than
the pre-eruption levels. What caused this? Not CO2 which steadily increased.
Since Pinatubo resolved circa 1995, there is no significant trend in strat temperatures, though strat temperatures are at a lower temperature than the 1950s.
That being said, reduction in strat temperature is not the only mechanism of
GHG forcing – band broadening is a significant action as well.
And this is what passes for science in the 21st Century! . . . It’s overloaded with unjustifiable assumptions and speculative in the most obvious and shallow fashion conceivable.
Marvellous – so CO2 causes both warming and cooling
By the way, there are a couple of other important points about CO2
both warming and cooling.
1. At nearly all levels, CO2 tends to cool the atmosphere:
http://www.aer.com/images/rc/lbl_clrt_mls.gif
though less effectively than H2O tends to cool.
The distinction is that while GHGs tend to cool the atmosphere,
they also tend to warm the surface, warming which is transported to the atmosphere.
2. The ‘forcing’, at least as far as the IPCC says,
is quite different from pole to equator, and from the surface to
the ‘top of the atmosphere’.
http://www.ipcc.ch/graphics/ar4-wg1/jpg/fig-2-23.jpg
http://www.ipcc.ch/graphics/ar4-wg1/jpg/fig-2-24.jpg
And what is this “slightly” increased Antarctic ice extent? It is one million+ square kilometers greater than the average. We make a big deal of a couple of hundred square kilometers more or less in the Arctic. The differences at any time between the two poles in ice anomaly is as much as an order of magnitude.
Does Judith know about the well-established phenomenon during interglacial periods known as the polar see-saw?
When the anomaly is positive at both poles, watch out!