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.
=====================================================
This lends credence to this related story previously on WUWT:
The full paper is here (PDF) backup location here Tietsche_GRL_2011
I am still waiting for the feedback loop.
From the brief reading I can’t see anything about increased clouds and increased albedo.
————–
Ice free Arctic ocean during the Holocene
http://dx.doi.org/10.1016/j.quascirev.2010.08.016
http://adsabs.harvard.edu/abs/2007AGUFMPP11A0203F
http://geology.geoscienceworld.org/cgi/content/abstract/21/3/227
Observed and predicted effect of clouds
http://earthobservatory.nasa.gov/Features/ArcticReflector/arctic_reflector2.php
“So in addition to changing sea ice, we can kind of guess that something must be happening in the atmosphere over the Arctic, too.” Clouds are bright, too, and an increase in clouds could cancel out the impact of melting snow and ice on polar albedo.”
http://earthobservatory.nasa.gov/Features/ArcticReflector/arctic_reflector4.php
“Although sea ice and snow cover had noticeably declined in the Arctic from 2000 to 2004, there had been no detectable change in the albedo measured at the top of the atmosphere: the proportion of light the Arctic reflected hadn’t changed. In other words, the ice albedo feedback that most climate models predict will ultimately amplify global warming apparently hadn’t yet kicked in.”
http://www.ldeo.columbia.edu/res/div/ocp/pub/gorodetskaya/irina_ipccpaper.pdf
“The predicted substantial decrease in Arctic summer sea ice concentrations during the twenty-first century may favor cloud formation, which should diminish or even cancel the ice-albedo feedback by shielding the surface.”
(Dong et al. 2001).
I really wish people would stop coming up with these studies that show that it isn’t “worse than we thought.” I was hoping to purchase some super cheap soon-to-be-inundated sea-side property. /sarc
No, pls don’t. The “/” already means “off”, so “/sarc off” would mean something like “off sarc off”, and it’s too late at night for my brain to grok the semantics of that.
<:-p
As for absorption of IR, my understanding was that what ever absorbs equally emits, so open water would radiate 24/7, and the tropopause and space are very close in the polar regions …
Werner Brozek says:
February 9, 2011 at 7:51 pm
“P.S. “high reflectance at low angle of incidence” The angle of incidence is measured from the normal so it should be “high reflectance at high angle of incidence””
Thanks for the correction. I was thinking angle of elevation but wrote incidence instead.
Werner Brozek says:
February 9, 2011 at 7:51 pm
“But is there not also an increased negative feedback if the precipitation falls as snow and then the liquid water cools off still more in melting the snow due to the latent heat of fusion?”
Latent heat of fusion is only 15% that of vaporization but that certainly does add significantly to the negative feedback. In a different thread talking about the 1998 El Nino I speculated that the pulse of warm water traveling near the surface toward the pole ended up a couple of years later dumping its heat into melting of arctic ice and because the heat of fusion is latent it would show up as warmer arctic air but rather just an accelerated ice loss. If you look at ice extent history, velocity of warm surface conveyor belt, it lines up pretty good – ice melt accelerated around 2000-2001 and lasted for about 5 years at the high rate then diminished. I figure a La Nina of equal and opposite magnitude should undue the ice melt from the grand El Nino.
I wish that map were real. In the long run what a boon to human civilization it would be if the Arctic and Antarctic were ice free, the extra room and resources, and I doubt that the tropics would be that much warmer.
Hence, hysteretic threshold behavior (or a “tipping point”) …
P. Solar says:
February 9, 2011 at 5:44 pm
“Don’t they mean hysteric threshold behavior ?”
Nope, nothing hysterical in it. They’re talking about a hysteresis theshold.
Sorry mods, I didn’t turn of the italics.
Stupid.
“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?”
SANTA WILL DROWN!
YOU want to be the one to drop the news to my kids? Be. My. Guest.
/silliness
R Gates, who is a self confessed partial sceptic/partial believer in the church of CAGW, no has some personal soul searching to do…
Should he go out and celebrate that the Arctic death-spiral has been disproved?
Should he doubt the computer model used to show the lack of death spiral?
Should he throw his toys out of his pram and continue to believe in the death spiral, while continuing to assert that computer models are correct?
Answers on a post-card please…:)
I don’t recall any GW theorists positing that the Arctic would be ice-free year-round due to global warming. The GRL paper simply states what’s already known: that the Arctic is “unlikely” to warm up enough this century for it to remain free of ice for the entire year. Of course it will refreeze every winter. What GW theorists have been predicting is that every winter less and less ice will form, and every summer more and more will melt. And that is precisely what is happening.
Remember: the GRL is published by the American Geophysical Union, which made the following statement: “The Earth’s climate is now clearly out of balance and is warming. Many components of the climate system–including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation, and the length of seasons–are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century.”
Neapolitan says:
February 10, 2011 at 11:02 am
“The GRL paper simply states what’s already known: that the Arctic is “unlikely” to warm up enough this century for it to remain free of ice for the entire year.”
Nobody has been talking about that. The GRL paper refutes the previous opinion, that a summer ice free arctic marks a tipping point.
Previously broadcasted strong positive feedbacks – a favourite of media scare -, are not strong at all and actually there are pretty strong negative feedback mechanisms instead.
Tenuc says:
February 10, 2011 at 9:30 am
R Gates, who is a self confessed partial sceptic/partial believer in the church of CAGW, no has some personal soul searching to do…
Should he go out and celebrate that the Arctic death-spiral has been disproved?
Should he doubt the computer model used to show the lack of death spiral?
Should he throw his toys out of his pram and continue to believe in the death spiral, while continuing to assert that computer models are correct?
Answers on a post-card please…:)
_____
First, this model simulation proves nothing. It simply shows what might happen under the parameters input into the model. “Tipping points” or nonlinear threshold behavior can never be accurately predicted before the occurrence. Not one GCM accurately predicted the 2007 steep decline in Arctic Sea ice.
In terms of an seasonally ice-free summer Arctic, which is what the Arctic is headed toward this century, this is what was originally meant by “death spiral”– that the arctic would be ice free in the summer. It was never meant to mean that the Arctic would remain ice free into the fall and winter, and not one model showed that it would. The biggest issue with this research is that it ignores the other research done on the larger issue of what real effects the release of all that heat from the open ocean will actually have during the fall and winter. The many other research studies have shown significant changes in atmospheric circulation as the result of the release of this heat later in the season, and yet this study, for some reason, simply assumes it will just go right out the TOA, with virtually zero effect on the local or N. Hemisphere climate. So in essence, the study is saying…okay, yep, we’re headed for a seasonally ice free Arctic, but no worries, it won’t affect a thing and it will recover quickly because of natural balancing mechansims. If we’ve learned anything from the study of ice-cores, it’s that the climate does have tipping points where the atmosphere and ocean shift into entirely new modes very very rapidly. In short, I find this study interesting, but hardly proof of anything, especially proof that a tipping point doesn’t exist, when such tipping points are part of a nonlinear chaotic process and could never be predicted to either occur or not occur by any such model.
Further to my earlier posting. I’ve just updated my calculation of sea ice thickness. It is currently well above its 10 year average. See:
http://www.climatedata.info/Impacts/Impacts/seaice.html
Neapolitan says:
February 10, 2011 at 11:02 am
I don’t recall any GW theorists positing that the Arctic would be ice-free year-round due to global warming. The GRL paper simply states what’s already known: that the Arctic is “unlikely” to warm up enough this century for it to remain free of ice for the entire year. Of course it will refreeze every winter. What GW theorists have been predicting is that every winter less and less ice will form, and every summer more and more will melt. And that is precisely what is happening.
From the bullet points below IJIS’s daily graph of Sea Ice Extent
“In principle, SIC data could have errors of 10% at most, particularly for the area of thin sea ice seen around the edge of sea-ice cover and melted sea ice seen in summer. Also, SIC along coastal lines could also have errors due to sub-pixel contamination of land cover in an instantaneous field of view of AMSR-E data”
Since the variations from the long term average of the winter peak sea ice seem to fall mostly within the measurement error of the system, I’d have to suggest a big old “WE DON’T KNOW THAT”
R. Gates says:
February 10, 2011 at 11:32 am
Your previous position was, that a tipping point would be caused by positive feedbacks and triggered by shrinking sea-ice.
That was false from the beginning, as most likely sea ice has been as low as currently in the past and nothing happened.
Your new position is, that shrinking sea ice causes all sorts of effects, and a consequence could be a tipping point, because tipping points in your opinion unpredictable and ice core data shows, that there have been tipping points in the past.
Now that is very lame and completely unrelated to facts, though I haven’t expected anything else.
1. The new feedbacks which have been publioshred recently (in this settled science) are actually negative throwing over what we have heard until very recently. The heat, the increased coud cover and increased snow falls, all negative feedbacks.
2. At the current postion of the continents, the solar activity, the position of the earth within the galaxis, the angle of the rotational axis, etc., there have been only 2 stable states in the past geological history: around current temperatures and 12 degree colder ice-ages.
This means, there was only 1 tipping point, at a temperature somewhere between these stable states. Everything else is pure fantasy. Any deviation above current temperatures or below ice age temperatures has been corrected naturally by negative or non-positve feedbacks. The is no historical evidence for a tipping point a few degrees above current temperatures under above conditions.
Actually, as temperatures have declined gradually during the past few thousand years, the small increase due to CO2 should be beneficial and lower the risk of triggering the only, lower tipping point.
@ur momisugly Ross Brisbane,
What a relief that you survived cyclone Yasi. It’s a shame, that your panic got twisted into an incoherent snideness.
Is there anything that can be done to help?
“Dave Springer says:
February 10, 2011 at 6:12 am
…because the heat of fusion is latent it would show up as warmer arctic air but rather just an accelerated ice loss.”
I assume you meant …because the heat of fusion is latent it would NOT show up as warmer arctic air but rather just an accelerated ice loss.
This brings up an interesting question: Could Trenberth’s “missing heat” possibly then be in the form of greater ice loss rather than an increase of temperature somewhere?
The only problem I have is how to explain to my grandkids why Santa is living underwater.
It is not only in the relatively distant Holocene that Artic Ice has been dramatically reduced. As late as the period 1920-1940 the withdrawl of Arctic Ice was greater than today. I pointed evidence for this in the post a month or so ago, but unfortunately it seems to have disappeared into the ether.