From the AGU Journal Highlights, some news that NSIDC’s “death spiral” has zombie like characteristics, and that the ice may quickly return from the dead, even if the Arctic turned ice free during summer. Nature is more resilient it seems, than some people give it credit for.
No tipping point for Arctic Ocean ice, study says
Declines in the summer sea ice extent have led to concerns within the scientific community that the Arctic Ocean may be nearing a tipping point, beyond which the sea ice cap could not recover. In such a scenario, greenhouse gases in the atmosphere trap outgoing radiation, and as the Sun beats down 24 hours a day during the Arctic summer, temperatures rise and melt what remains of the polar sea ice cap. The Arctic Ocean, now less reflective, would absorb more of the Sun’s warmth, a feedback loop that would keep the ocean ice free.
However, new research by Tietsche et al. suggests that even if the Arctic Ocean sees an ice-free summer, it would not lead to catastrophic runaway ice melt.
The researchers, using a general circulation model of the global ocean and the atmosphere, find that Arctic sea ice recovers within 2 years of an imposed ice-free summer to the conditions dictated by general climate conditions during that time. Furthermore, they find that this quick recovery occurs whether the ice-free summer is triggered in 2000 or in 2060, when global temperatures are predicted to be 2 degrees Celsius (3.6 degrees Fahrenheit) warmer.
During the long polar winter the lack of an insulating ice sheet allows heat absorbed by the ocean during the summer to be released into the lower atmosphere. The authors find that increased atmospheric temperatures lead to more energy loss from the top of the atmosphere as well as a decrease in heat transport into the Arctic from lower latitudes. So the absence of summer sea ice, while leading to an increase in summer surface temperatures through the ice-albedo feedback loop, is also responsible for increased winter cooling. The result is a swift recovery of the Arctic summer sea ice cover from the imposed ice-free state.
Title:
“Recovery mechanisms of Arctic summer sea ice”
Authors:
- S. Tietsche, D. Notz, J. H. Jungclaus, and J. Marotzke
- Max Planck Institute for Meteorology, Hamburg, Germany
Source:
Geophysical Research Letters (GRL) paper 10.1029/2010GL045698, 2011
GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L02707, 4 PP., 2011
doi:10.1029/2010GL045698
Recovery mechanisms of Arctic summer sea ice
S. Tietsche, Max Planck Institute for Meteorology, Hamburg, Germany
D. Notz, Max Planck Institute for Meteorology, Hamburg, Germany
J. H. Jungclaus, Max Planck Institute for Meteorology, Hamburg, Germany
J. Marotzke, Max Planck Institute for Meteorology, Hamburg, Germany
We examine the recovery of Arctic sea ice from prescribed ice-free summer conditions in simulations of 21st century climate in an atmosphere–ocean general circulation model. We find that ice extent recovers typically within two years. The excess oceanic heat that had built up during the ice-free summer is rapidly returned to the atmosphere during the following autumn and winter, and then leaves the Arctic partly through increased longwave emission at the top of the atmosphere and partly through reduced atmospheric heat advection from lower latitudes. Oceanic heat transport does not contribute significantly to the loss of the excess heat. Our results suggest that anomalous loss of Arctic sea ice during a single summer is reversible, as the ice–albedo feedback is alleviated by large-scale recovery mechanisms. Hence, hysteretic threshold behavior (or a “tipping point”) is unlikely to occur during the decline of Arctic summer sea-ice cover in the 21st century.
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This lends credence to this related story previously on WUWT:
The full paper is here (PDF) backup location here Tietsche_GRL_2011
“hysteretic threshold behavior” – oooh, I like it. Could this be used by Josh?
Yet another general circulation model? Hmmm…
He said “model”. /snarky comments here/
Unless this model is able to deal with complex chaotic systems I’d have to consider it as useful as the much disdained climate models. Which leaves us with the question: What do observations tell us?
REPLY: See the related story at the bottom – Anthony
ouch, reality bites back … another “reasonable” theory forgets to consider the entire system …
So the absence of summer sea ice, while leading to an increase in summer surface temperatures through the ice-albedo feedback loop, is also responsible for increased winter cooling.
Don’t let Krugman, Gore, Page, McKinney, etc. know about this, they’ll think they are correct about AGW causing this winter’s snowstorms!!
Now who would have thought that without a lid on it, more heat would escape….
..and that computer cost how much?
I wonder if they started this to find the tipping point due to positive feedback and found enhanced negative feedback instead. Damn, there goes next year’s funding.
This really underlines the fact that nature has lots of defensive tricks. The only downside is that the conclusion came from one of these admired and trusted GCMs….
One argument frequently made is that as the ice decreases, so goes the albedo, and this accelerates the warming.
One argument I do not see is that same effect being applied to the huge non-arctic areas covered in snow during these winter blizzards we’ve been enjoying. Whether 13mm 130m thick, the albedo is the same, and however relatively brief, it has a feedback effect.
Is that in the GCM’s?? I’m doubtful.
Although I don’t always put a lot of faith in the models in predicting how the climate itself may change, this is a bit more interesting to me. They were comparing the results using todays temperatures with 2 degrees C higher temperatures (in 2 model runs).
So even if the model isn’t duplicating ALL the ‘nuances’ of the atmosphere, it is doing the same thing in both cases. And it gives results that, frankly, aren’t really surprising to me (based on all I have read about the arctic, other periods of low ice or ice free, etc. ) .
From http://meetingorganizer.copernicus.org/EGU2009/EGU2009-8882.pdf
“Future recovery of summer Arctic sea ice loss
S. Tietsche, D. Notz, W. Müller, J. Jungclaus, and J. Marotzke
During the 21st century, the Arctic Ocean will very likely experience a transition from perennial to seasonal sea ice cover owing to anthropogenic climate change. Will this transition be gradual, or is there a critical threshold for the summer sea ice extent, below which the ice-albedo feedback inhibits the recovery of summer sea ice?
We examine this question using the global atmosphere-sea-ice-ocean model ECHAM5/MPI-OM. For the IPCC emission scenario A1B, the model predicts that the Arctic Ocean is essentially ice-free in September from the 2070s on. For the transition time period before that, we perform a series of experiments for which we artificially remove the Arctic sea ice in one summer, analyzing the changed ice cover in the following years.
First results indicate that, for the climate of the first half of the 21st century, Arctic sea ice recovers from summer ice-free conditions within a year. We investigate the mechanisms that mitigate the ice-albedo feedback and restore the state of the summer sea ice. We do not find a ‘tipping point’ for climate states with small Arctic sea ice caps. Hence, a smooth transition from perennial to seasonal Arctic sea ice cover can be expected.”
So the decline of the ice cap will be gradual, not sudden? And we might have ice up through 2070? Good to hear.
Our results suggest that anomalous loss of Arctic sea ice during a single summer is reversible, as the ice–albedo feedback is alleviated by large-scale recovery mechanisms.
However that wouldn’t necessarily be the case in a response to a steady decline in sea ice if conditions are consistently changing.
It appears that the hysterical behavior of some scientists over the possible hysteretic threshold behavior of polar ice is a waste of “scientific” energy that we could all wish was conserved. The calm and thorough work of the scientists at Max Planck is warmly welcomed.
Compare their model predictions with projections based on a statistical model of area data. http://www.kidswincom.net/arcticseaice.pdf. Place your bets and enjoy.
The ice cores document that the earth’s climate is a self-regulating, chaotic system in which temperature oscillates in approximately 100,000 year cycles between self-limited upper and lower boundaries. Neither catastrophic meteor strikes nor cataclysmic volcanic eruptions made any noticeable dent in that monotonous cycle.
Of course the arctic sea ice is self-regulating! Of course man-mad “tipping points” are absurd. The obvious mystery is why, in view of documented climatic history, anyone would believe a quarter-inch, man-made, CO2 tail (by volume) could wag a one-hundred-yard-long atmospheric dog?
Well there’s that “model” word again. Well without models we would just have to sit and wait it out to watch it become ice free.
Actually, I’m less put off by a Teracomputer model of an ice free arctic. I could swear that in that photograph of the last time the arctic was ice free, that virtually ALL of the surrounding lands in that ice free ocean are actually completely inundated with ice; well snow anyway.
And that’s about what my 1/4 byte stick in the sand computer says would happen. Lots of open sea to evaporate; after all they did say it would get hot due to all the absorbed sunlight; “beating down on it” I believe is what they said.
I can just picture the sun beating down on the north pole; and never ever getting above 23 1/2 deg altitude. By my calculations the path from sun to pole is always longer than Air Mass 2.5. Yeah the sun really gets unbearable after going through that much air.
But to get serious; I think this is a useful study. A much simpler system, than the whole kit and caboodle, so the model could be much more lifelike; you know like Mother gaia’s model.
I’ll have to digest this one; looks like it might be a keeper.
On one foolish excursion over there at c-r I did happen to catch a post wherein Peter Humbug said he had removed all the H2O from the atmosphere; and then let her rip, with all that CO2 there to globally warm by itself. He said he got ALL of the H2O back in the atmosphere within three months.
If I mistook you there Peter; my apologies; only question is, did you happen to drop the whole surface Temp to zero deg C as well, which would have helped you tweezer out those last pesky H2O molecules. If you haven’t done that; give it a whirl and let us know what you find. My 1/4 byte stickputer says you still get it all back quickly.
That water/cloud feedback is a flaming nuisance to established science.
Greenland has been considerably warmer than it presently is. This warmer period must have had an effect on the extenmt of Artic ice. Presumably during the Roman Warm Period, Medieval Warm period etc, the summer Aartic ice extent would have been far less, indeed the Artic might well have been ice free during summer. Yet we know as fact that no tipping point was reached during those warm periods and that Artic ice recovered as conclusively proved by the fact that during the current period in which we live in the Artic still possess summer ice.
Phil,
Conditions are always changing. The takeaway from the study is that the equilibrium state for the Arctic is to have ice, even if the temperature was higher than it is now. That the ice is undergoing lots variation at the moment only means only that. If there was 100 years of satellite data the amount of worry would be much less.
Let’s say the arctic ice caps melts, what is the worst that can happen? Ice that is already in the ocean won’t rise the sea level, so what’s the alleged problem?
I vaguely remember a study from a few years back that found that as sea ice decreased, evaporation from the polar seas resulted in an increase in low level clouds, which in turn bounced a lot of sunlight back into space.
Love this Quote Claude Harvey,
“The obvious mystery is why, in view of documented climatic history, anyone would believe a quarter-inch, man-made, CO2 tail (by volume) could wag a one-hundred-yard-long atmospheric dog?”
Good one!
They need a model to tell them that less ice in the winter means greater outgoing radiation? ? ???? ? Really???????
I can only imagine the faucets in the houses of AGW modellers. C and H could be on either side. Additional faucets for CW and WC are “de rigeur” and then you cannot actually use them, you have to apply for a grant and then simulate their activity…
/sarcoff
Ju. P. Doronin determined this in 1968 in his paper “On the problem of iradicating the Arctic ice” in “Probl. Arkt. Antarkt.”, 28, 21-8. As sourced by H. Lamb in vol. 1 of “Climate: Present, Past and Future.” p. 339
Funny, my model says ice will form in sub-freezing waters, too. Weird…….
“the Sun beats down 24 hours a day during the Arctic summer, temperatures rise and melt what remains of the polar sea ice cap.”
I have trouble with this. The Sun is at a max angle of 23.4 degrees at peak summer and at that time solar energy is 20% of direct vertical Sun (and on average only half of this during the summer) and only 17% of that due to absorption through the long path length through the atmosphere. That’s 3.4% of the normal solar energy of 1370 W/ sq m or about 80–48 W/ Sq m (half of this on average, 40–24 W/sq m). This is the Sun BEATING DOWN(?) 24 hours a day? This is not a significant energy input and any energy absorbed by the water would be lost as evaporative heat loss in seconds.
And let’s not forget that the reflection of light off water increases as the angle decreases. So, we are also being generous with the absorption versus reflection. Most melting that occurs in the Arctic is from warm air and water from the South. Solar input is pathetic and obviously much over-rated by the alarmists.
Where do they get the opinion that the Arctic summer is warm? It’s certainly not!
You could say that the average energy is less than half of the peak 80–48 W/sq m because, as the Sun’s angle goes even lower, the absorption and spreading of the energy increases nonlinearly. I would put the average, generously, at 27–18W/sq m (2.0–1.3% of normal, we get more on a cloudy day). This will make no difference to the Arctic climate compared to incoming weather effects.
This is also neglecting immediate losses of energy to space. Losses to space during the dark Arctic winter are obviously the dominant (only) effect with warmer air sucked northward as dense, cold Arctic air masses descend towards the equator due to the Earth’s rotation.