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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“”” “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,” “””
WHAT PARADOX ??
Gaiaa doesn’t make paradoxes; she takes care to see that everything works exactly as it is supposed to; so for the last time; there is no Antarctic paradox !
If you guys (and gals) don’t know how or why it works, why don’t you say so; instead of implying that you do understand how it works; but it isn’t working that way. You and your blathering are the paradox; not Antarctica !
Dear Dr. Curry,
The press release begins with this sentence: “While Arctic sea ice has been diminishing in recent decades, the Antarctic sea ice extent has been increasing slightly.”
Cryosphere Today indicates that the global sea ice anomaly is currently positive by a half million sq. kilometers, indicating that currently the ‘slight’ increase in the south is larger than the decrease in the north. If we take running means of both icecaps over the satellite era, one could argue that we have seen a reduction of 1.2 to 1.5 million sq. kilometers of sea ice in the north, and an increase of about 1 million sq. kilometers in the south, which is not a huge difference. Would you not agree that the opening statement, which implies a significantly larger negative trend in the north than the positive trend in the south, is inaccurate and misleading?
The second sentence proclaims that it is paradoxical for Antarctic sea ice to be increasing while the climate is warming, but there has not been any warming of the Antarctic region as a whole over the last 50 years. Most of the so-called global warming has been in the Northern Hemisphere, much like it was during the historical MWP. Given that there has not been any warming of the Antarctic Region, would you agree that there is no paradox, apparent or otherwise, and that the use of the phrase is scientifically inaccurate and misleading?
If you acknowledge that the first two sentences are scientifically inaccurate and misleading, could you explain the motivation for writing them that way? If you do not agree that they are inaccurate and misleading, could you defend them, please?
One finally question: would you agree with the statement that this study assumes, from the very beginning, that CO2 induced AGW is a given (in line with IPCC projections) and only attempts to understand the observations in the context of that assumption, and, therefore, has no real value in the debate over the AGW theory?
Thank you for your response!
They are clueless. Happily it seems their co2 pseudoscience has only a few years life left.
“”” “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. “”
Izzere someone who would care to translate that into English, so we would know what they blazes she (I presume) is talking about ?
What means “the hydrological cycle accelerated” This sound like a button on my dish washer went haywire.
Could someone assume the role of a Maxwell’s Demon and give us a blow by blow of exactly what goson when “the hydrological cycle accelerates.” Maybe its a part of the Tour de France in the lake region.
People use these gobbledegook phrases as if they actually have some scientific meaning; so give us the 8th grade high school science version of just exactly what “acceleration of the hydrological cycle” is doing from start to finish.
And what is this business of precipitation in the Southern Ocean. If tropical waters evaporate, and deposit latent heat out in the upper atmosphere when clouds form, and those clouds move south and then it rains/snows/sleets/hails in the Southern ocean, does that convey more heat south or less heat south, than simply having ocean surface currents transport warmer triopical waters south; like the Gulf stream does in reverse in the Northern hemisphere ?
Wait a minute! If Antarctic ice extent has been “increasing slightly” and overall global ice is currently above the 30-year average, then how can the Arctic Ice be in a “death spiral”?
Enquiring minds want to know!
I don’t often get snarky. This article closes with the dumbest thing I’ve ever heard a scientists say:
What an absolutely ridiculous statement.
Sam Clemens was standing on a porch one day with some friends, watching it rain cats and dogs. One gentleman mused, “Wow, do you think it will ever stop?”
Clemens replied, “It always has.”
[That is the joke. Laugh now.]
Do we put this in the “It always has” category? In the “WTF?” category? How about the “No duh” category?
OF COURSE WITHIN THE NEXT FEW DECADES THE ICE EXTENT WILL DECREASE. IT IS AN OSCILLATION.
This is like two people sitting on a bench watching a very long pendulum swinging up toward one high point and one asking if it will keep going up and up forever. The other one slowly slides to the far end of the bench…
“We may see”??? MAY?
We MAY see the Sun appear in the northeast tomorrow morning.
We don’t want to hold you to this rock solid, scientifically based prognostication, Ms Curry. Science is supposed to be about SOLID predictions. Curry can’t even say unequivocally that SOME DAY the ice extent might actually start to shrink. Something as certain as the Sun coming up tomorrow, and she is waffling on it.
The problem is that she knows she is just flapping her gums. The reporters seemed not to notice and duly wrote it down.
“What means “the hydrological cycle accelerated”
When I use the term it means more and faster evaporation leading to more and faster convection with cloud forming sooner than it otherwise would have done with rainfall heavier than it otherwise would have been.
The energy budget result is faster transport of energy from the surface to higher levels in the atmosphere. However no rise in humidity occurs as per the steady optical depth of 1.87 over the past 61 years. The increased speed of the cycle prevents the increased evaporation from adding to total global humidity.
Note that because water vapour is lighter than air an increase in evaporation results in more convection without any need of a higher surface temperature.
The concept of a variable speed for the hydrological cycle is essential for an appreciation of why and how climate changes occur.
Once an AGW proponent concedes that a variable speed for the hydrological cycle is possible (and without a rise in surface temperature) then that provides a mechanism for negating any attempt at surface warming by GHGs over water.
There will be warming over land though but on Earth that will be negated by our 70% ocean surface as oceanic air flows into and out of continental areas. Furthermore warming over land by day is swiftly lost at night whereas diurnal differences are much reduced over water.
Judith has exposed AGW’s most vulnerable flank.
Julian Braggins says:
August 17, 2010 at 12:45 am
Yep, you [and SSam] are right. My bad for not trying SSam’s code [without the leading zero] before posting, …still one wonders at the wisdom of having multiple codes for the same symbol.
George E. Smith says:
August 17, 2010 at 10:31 am
Evaporation from the oceans cools it and cools the adjacent troposphere in so doing. “Tropos” means change — it is where all the change, or circulation, occurs. In water vapor form, the stored energy (enthalpy) is given up to the upper troposphere through the tropopause, and beyond, eventually into space, mostly by conduction or, predominantly, radiation (the tropopause inhibits convection and conduction). It condenses into water (clouds) and gives up the latent heat of evaporation.
It coalesces (don’t say “condenses” — it already has done this) into large cold droplets (much of the heat has already been removed) which then cool the seas accordingly, adding either cold water or snow to the land and sea.
So heat has been removed from the tropic/subtropic zones, heat removed from earth, and precipitation is mostly deposited relatively locally before the now dry air would reach either pole. [especially dry when it is exhausted of moisture well before it reaches the drier south pole]
To: Dennis Wingo
Using measurements from the Argo network of profiling floats and historical oceanographic data, a more-recent analysis detected that the Southern Ocean
became fresher since the 1960s, which extends to depths of more
than 1,000 m (Boning CW, Dispert A, Visbeck M, Rintoul SR, Schwarzkopf FU, 2008).
Summary: They don’t know WTF is going on in Antarctica with any certainty what-so-ever….
BTW, we are at record-levels of ice in the southern hemisphere. It has nowhere to go but down….
Wow reality trumping fiction as snowing in antarctica is now considered a paradox.
Wonder what they calla an normal warm day in sahara, a freak of nature?
Alex the Skeptic says…
Snowlover123, the reason why you do not get money grants for doing science is because you say it so simply and truely. You must add some spice into your statements, like “the end of the world is nigh”, or ” we re all gonna die of the heat” or later on “we re all gonna die of the cold” or ocean inundations or whatever. But saying the simple truth will not get you any money grants, sorry. You shall die of hunger before the heat gets you, while the “true” scientists shall inherit the (scorched) earth. Sarc off.
http://wattsupwiththat.com/2010/08/16/georgia-tech-on-resolving-the-paradox-of-the-antarctic-sea-ice/#comment-459424
————————
Haha I guess that’s how Keith Olberman and Chris Matthews make their money off of the liberal media! 😉
Tom in Texas says…
“…a switch in the Antarctic, where the sea ice extent begins to decrease…”
About the same time the Arctic sea ice extent begins to increase?
———
Yep. That’s something the alarmist media “forgot” to mention… 🙂
I have to applaud Judith Curry on having the guts to present her paper in the boxing ring of climate blogs where the wild and ignorant rule. but also these that think unbiased and try to address problems in creative ways. I just hope she was not counting on any mercy here.
“For the last half of the 20th Century, as the atmosphere warmed”
I thought the recent warming started in the 70’s. Last 30% doesn’t sound as impressive, but it does sound (1) more accurate and (2) like half of a PDO 🙂
>> Jiping Liu says:
August 17, 2010 at 11:24 am
Using measurements from the Argo network of profiling floats and historical oceanographic data, a more-recent analysis detected that the Southern Ocean
became fresher since the 1960s, which extends to depths of more
than 1,000 m (Boning CW, Dispert A, Visbeck M, Rintoul SR, Schwarzkopf FU, 2008). <<
The Argo floats have only been there since 2003 (IIRC). How accurate are salinity measurements 1000 m deep in the Antarctic ocean before that? How many salinity measurements were taken there, and at what depths?
Jim Clarke,
The follow statement is correct:
“While Arctic sea ice has been diminishing in recent decades, the Antarctic sea ice extent has been increasing slightly.”
It is a qualitative statement. You can talk about the increase/decrease in terms of sq km or in terms of % area.
The observed sea surface temperatures in the Southern Ocean shows an overall increase during the period 1960-present. Yes, there are short term ups and downs, and regional variability. But overall, the surface temperature has increased in the Southern Ocean. Note, the trend for the Southern Ocean is different from that of the Antarctic continent.
In summary, I don’t see that either of these statements are inaccurate or misleading. Any statement is of course open to misinterpretation, but that is in the eye of the beholder.
The paper does not assume anything about the attribution of the 20th century warming. The paper then discusses the scenario whereby CO2 would increase surface temperatures, and investigates how the processes and balances would change in a warmer climate.
I don’t think this paper has any particular importance for the debate over AGW theory. It is an interesting paper that unravels some physical mechanisms that explains why the Antarctic sea ice is increasing in spite of a warming climate. The main significance in the AGW debate is that some skeptics use evidence of growing Antarctic sea ice as evidence that there is no AGW. Such an increase in Antarctic sea ice cannot be used as evidence against AGW given the arguments we have put forth.
Lucy VC, not interested in mercy. Still scanning for some thoughtful questions that I will respond to.
Stephen Wilde says:August 17, 2010 at 11:01 am
Judith has exposed AGW’s most vulnerable flank.
Perhaps, because Judith’s been twittering around trying to coalesce CAGW and skeptic groups into one great big group hug………………And then this. How does this add anything to science.
From your paper:
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.
1. At what temperature will precipitation change from snow to rain? Make your thesis falsifiable or you just posturing for grants and you know it. Enough of the mays, possibility, etc.
2. Does your model take into account the increased cloudiness resulting from increased rain resulting from ever increasing temperature.
3.I didn’t know that snow reflected heat. I thought it reflected sunlight. By the way, how much sun does Antarctica get? How much less snow must fall down there with low albedo. Are you sure that more rain will fall, but not more snow also.
.This increased precipitation, mostly in the form of snow, stabilized the upper ocean and insulated it from the ocean heat below. …………………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.
1.Your thesis on this point is that higher temps lead to more precipitation. Mostly snow now, insulating the surface water from heat below. Increasingly temps will cause more rain. So, I’m confused by the circular logic. The rain falling is bound to be cold. No tropical rain down under. What temperature is the falling rain? Does your computer model show any sleet? How about wet slushy snow. And, with increasing catastrophic temperature, the precipitation will increase even more and the area will get a greater volume of cold rain. What must the temperature of the cold rain be and what increased volume is necessary to maintain the absolute temperature of the upper ocean surface from upwelling heat from below. At what magic tipping point does the surface temperature of the water fall beneath to allow upwelling heat? Have you done an energy calculation? How much more cooling rain must fall relative to slightly colder snow to inhibit upwelling warm water?
This paper is a big disappointment. I expected a little better from you. Another paper submitted with the aid of cronyism. Similar to this one also submitted:
Solomon M. Hsiang
Temperatures and cyclones strongly associated with economic production in the Caribbean and Central America
PNAS published ahead of print August 16, 2010,
Understanding the economic impact of surface temperatures is an important question for both economic development and climate change policy. This study shows that in 28 Caribbean-basin countries, the response of economic output to increased temperatures is structurally similar to the response of labor productivity to high temperatures, a mechanism omitted from economic models of future climate change. This similarity is demonstrated by isolating the direct influence of temperature from that of tropical cyclones, an important correlate. Notably, output losses occurring in nonagricultural production (–2.4%/+1 °C) substantially exceed losses occurring in agricultural production (–0.1%/+1 °C). Thus, these results suggest that current models of future climate change that focus on agricultural impacts but omit the response of workers to thermal stress may underestimate the global economic costs of climate change.
Their thesis? When it gets hot, the islanders don’t work. Well doh. Apparently, you consider this good company.
Judith Curry says: August 17, 2010 at 1:37 pm
“The main significance in the AGW debate is that some skeptics use evidence of growing Antarctic sea ice as evidence that there is no AGW. Such an increase in Antarctic sea ice cannot be used as evidence against AGW given the arguments we have put forth.”
Here we get into the subtleties of the debate. I have seen very few skeptics who “use evidence of growing Antarctic sea ice as evidence that there is no AGW.” I for one have a reasonable degree of confidence in the basic tenants of the AGW hypothesis. However, I think it is quite appropriate that “some skeptics use evidence of growing Antarctic sea ice as evidence that there is no” CAGW. The Catastrophic Anthropogenic Global Warming narrative is based on a fragile patchwork of suspect data, questionable assumptions, speculative positive feedbacks and flimsy models. At present, we don’t understand how the sun works, we don’t understand how the clouds work, we barely understand how the oceans work and volcanic activity is a complete wild card. Our understanding of Earth’s climate system is rudimentary at best. We have 130 years of highly suspect surface temperature data and 31 years of reasonably accurate satellite data, on an approximately 4.5 billion year old planet. Our understanding of the history of Earth’s climate system and its average temperature is rudimentary at best. Based on our limited understanding of Earth’s climate system, any predictions about Earth’s climate system and the long term trajectory of its average temperature are, at best, educated guesses. We are still learning how to accurately measure Earth’s temperature, much less accurately predict it 50 – 100 years into the future.
Further confounding any analysis of Earth’s climate system, is that there seems to be reasonable evidence of a significant ocean component based on the cycles of the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation;
http://icecap.us/docs/change/ocean_cycle_forecasts.pdf
http://www.appinsys.com/GlobalWarming/PDO_AMO.htm
http://www.atmos.washington.edu/~mantua/REPORTS/PDO/PDO_egec.htm
http://www.atmos.washington.edu/~mantua/REPORTS/PDO/PDO_cs.htm
And there also may be a significant volcanic component based historical observation:
http://www.geology.sdsu.edu/how_volcanoes_work/climate_effects.html
http://www.longrangeweather.com/global_temperatures.htm
http://www.agu.org/pubs/crossref/2009/2008JD011222.shtml
If you look at all of the potential variables involved in Earth’s climate system;
http://www.physicalgeography.net/fundamentals/7y.html
http://oceanservice.noaa.gov/education/pd/climate/factsheets/whatfactors.pdf
it seems like folly to assign primary driver status to any variable when we have a rudimentary understanding of such an astoundingly complex system.
As such, while “an increase in Antarctic sea ice cannot be used as evidence against AGW” I think that the trends in Antarctic Sea Ice Extent;
http://nsidc.org/data/seaice_index/images/s_plot_hires.png
and Global Sea Ice Area;
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
can reasonably be used as evidence against the Catastrophic Anthropogenic Global Warming narrative.
“”” bubbagyro says:
August 17, 2010 at 11:17 am
George E. Smith says:
August 17, 2010 at 10:31 am
Evaporation from the oceans cools it and cools the adjacent troposphere in so doing. “Tropos” means change — it is where all the change, or circulation, occurs. In water vapor form, the stored energy (enthalpy) is given up to the upper troposphere through the tropopause, and beyond, eventually into space, mostly by conduction or, predominantly, radiation (the tropopause inhibits convection and conduction). It condenses into water (clouds) and gives up the latent heat of evaporation.
It coalesces (don’t say “condenses” — it already has done this) into large cold droplets (much of the heat has already been removed) which then cool the seas accordingly, adding either cold water or snow to the land and sea. “””
So here’s what i actually did say :-
“”” And what is this business of precipitation in the Southern Ocean. If tropical waters evaporate, and deposit latent heat out in the upper atmosphere when clouds form, and those clouds move south and then it rains/snows/sleets/hails in the Southern ocean, does that convey more heat south or less heat south, than simply having ocean surface currents transport warmer triopical waters south; like the Gulf stream does in reverse in the Northern hemisphere ? “””
So where was it now that I said condenses ? or any of that stuff about enthalpy. It seems I did say that the process transfers a lot of latent heat to the upper atmosphere; doesn’t matter to me where that is, it is heat removed from the ocean and ultimately deposited where at least some of it can escape to space.
And if only dry air can reach the polar regions then where does all that ice and snow come from on Antarctica? We are continually bombarded with Antarctica is the driest continent on the planet; yet some how most of the fresh water on the planet is there; and it seems that we only get fresh water as a result of either evaporation from where it is warm enough to evaporate or sublime, or from the freezing of salty ocean water. So why does Antarctica have all the fresh water ?
This from the Georgia Tech article:
“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 this:
However, the climate models predict an accelerated warming exceeding natural variability with increased loading of greenhouse gases in the 21st century.
And this from Judith Curry’s comment:
I don’t think this paper has any particular importance for the debate over AGW theory…
The trick is to tag-team with the other authors to avoid blatant self-contradiction; and to almost-say or almost-imply with cunning shifts whereby a speculation or assumption is deftly transformed to a fact-base for further speculations and assumptions.
When all else fails, there’s the princess routine: that lofty and wistful yearning for a “thoughtful question”.
paulhan: You asked, “The PDO has switched to it’s cool phase, the AMO is about 10 years behind that in this cycle, and both of these are Northern Hemisphere phenomena. As the PDO continues cooling we will see increasing Arctic ice and stasis in the Antarctic.”
No reason to believe so. The PDO does not represent the SST anomalies of the North Pacific north of 20N. A negative PDO represents a pattern where the SST anomalies are cooler in the east than they are in the central and western North Pacific.
http://bobtisdale.blogspot.com/2009/04/misunderstandings-about-pdo-revised.html