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 atmosphereāocean 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 iceāalbedo feedback is alleviated by large-scale recovery mechanisms. Hence, hysteretic threshold behavior (or a ātipping pointā) 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
“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. MĆ¼ller, 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 ātipping pointā 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 iceāalbedo 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 80ā48 W/ Sq m (half of this on average, 40ā24 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 80ā48 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 27ā18W/sq m (2.0ā1.3% 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.
Homeostatis – the tendency of a system taken from its natural state to return back to its natural state. Carbon and oxygen are lagging indicators from when the sun overheats the surface and those levels increase. As the sun decreases so do the levels of those trace elements. The sun decreases in output and ice increases. Isn’t it amazing?
Climate research can do very peculiar observations and conclusions, however in my lifetime we don’t see icefree arctic. In ten years from this day, they warn us from new ice age, because multiyear ice in arctic grows rapidly. Climatescience is mostly pseudoscience. HAH!
MarkW says:
February 9, 2011 at 11:56 am
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.
1st rule of AGW:
Only use the data that fits the theory, mate. Ignore the rest.
Schrodinger’s Cat says:
February 9, 2011 at 11:12 am
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 yearās 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 GCMsā¦.
###
No no no, you got it all wrong! The growing ice PROVES CAGW! You just have to compensate for the negative feedbacks interfering with the warming signal.
It appears this “climate model” – and certainly the CAGW propagandists “must agree” with a model’s impartial and always-accurate results! – tears down the (false) tipping theory so often claimed about the Arctic ice.
1) The model did not assume any cause for the initial cause of the Arctic ice melt: The programmers merely began with an ice-free Arctic, then let the simulation run.
2) The simulation (model, if you will) was run under today’s conditions at today’s temperatures. Then it was re-run starting at a +2 degree initial condition and run again. With the same results -> The Arctic froze up again, just as in the first model run. (I will argue that an assumed +2 degree temperature by mid-century in unlikely/unrealistic under ANY circumstance, but that is irrelevant to the model runs.
That said, but ….
However, why do they bring up a 24-hour solar exposure? That occurs ONLY during the very few mid-summer northern hemisphere weeks centered at 22 June. Since nobody in any CAGW group is claiming/forecasting that the mid-winter ice will disappear (today’s winter temperatures are -25 to -35 average), and since the maximum ice coverage is Feb-Mar-April-May, discussing a June 22 ice-free Arctic is absurd.
Arctic minimum ice conditions occur 3 months later, just days before the fall equinox of 22 Sept. Thus, when the Arctic has minimum ice, the Arctic is exposed to (at most) 12 hours of sun. And that sun is (at msot) between 20 degrees and 5 degrees above the horizon. (About 1/4 of the Arctic Ocean starts north of Greenland’s north coast at about 82 degrees, a little over half is at 70-72 degrees north (from about longitude 120 W all the around to about 135 East) and the rest is open ocean between Greenland and the Murmansk Peninsula. (Roughly speaking.)
Since the land area of Canada, Alaska, and North Russia/Siberia always thaws every summer, albedo changes can only depend on the freezing or not freezing of the thin band of water between the dark (thawed) land and the “white” sea ice of the Arctic north of that land-sea border. Supposedly.
But at an angle of incidence of less than 22 degrees, just how much incoming sunlight is actually absorbed by the ocean – if any is absorbed at all? The atmosphere between 70 north and 90 north absorbs even more heat from the sun: You can see that every night when a setting sun is “easy” to look directly into every evening at dusk, while intolerable between 9:00 am and 3:00 pm the same day with the same clouds and the same dust, but with a atmosphere layer smaller by the tangent of the sun’s angle.
Great.
A group of scientists expend 2 or 3 years of valuable expertise and resources, which conclude by stating the bleeding obvious just to debunk another stupid warmist myth.
Little wonder that progress in better understanding the Earth’s climate system has slowed to a snails’ pace……….
Every summer since the sixteenth century (we don’t have reliable data further back) all ice in the Baltic has melted and the water has warmed up to bathing temperatures in the shallows. Every winter the water cools and the ice comes back. Judging from the fact that the Harbor Seal that depends on ice for pupping has survived since the Early Holocene there hasn’t been any long ice-free periods for at least several thousand years.
And lest somebody claim that it would be different in a deeper and saltier sea, it works just the same in the Okhotsk sea, which is both deep and salty. And so does the sea-ice in Antarctica which also largely melts and reforms every year in even deeper and saltier waters.
The idea that sea-ice wouldn’t come back once it has melted is completely unrealistic, and could only be due to the fact that most “climate scientists” seem to be remarkably ignorant about actual conditions at high latitudes.
“Zombie ice”
I like it. May I run with it?
I think the outline of a new Arctic ice-water circulation model is emerging slowly from where it was buried in 2007.
In 2007, the CO2 plague (thought to be carried by humans) melted away much of the Arctic in a “death spiral” that was expected to last until all ice was dead sometime between 2013 to 2030.
However, unexpected good news came from Catlin Arctic survey in 2009, when the scientific expedition led by a team of dogs-and-sleds explorers (no dog was harmed during the expedition) encountered “rotten ice”. This was bitter-sweet news for the expedition which went on to be surround by a host of rotten ice, and had to be rescued by air-lift. The question then was whether the rotten ice was the remnant of the perfectly good ‘live ice’ or the making of something truly rotten.
Well, with these findings scientists’ fears have been realised. It has now emerged that much of the recovery from 2007 is due to rotten ice growing and turning into “zombie ice”, which is an entirely different kind of ice than the one it replaced.
The ice that melted as a result of the CO2 plague was alive and it helped cool the planet. What effect ‘zombie ice’ will have on climate and biosphere is still unknown. It is suspected that ‘rotten ice’ may go through a process of purification in Arctic waters until it becomes alive again, but such a mechanism is poorly understood and is yet to be established. More research will be needed.
The Arctic ice-water circulation model:
Live Ice=> Death Spiral=> Rotten Ice=> Zombie Ice=> Purification?=> Live Ice
Do I need to add /sarc off to this?
Claude Harvey says February 9, 2011 at 11:37 am
But if you stuff it in a half-baked media bun and pour cheap red political ketchup all over it, there’s no mystery about folk finally chucking up after swallowing the tale. Frozen dough gets ’em every time.
lack of an insulating ice sheet allows heat absorbed by the ocean during the summer to be released …
Who would have thought that lack of insulation would increase blackbody radiation?
It seems the proponents of Catastrophic Anthropogenic Global Warming will spare no effort to catalog sources of heat, but are casual in identifying the sinks. One can draw a conclusion about agenda driven research verses pure scientific research.
Thanks for highlighting this story, Anthony.
If anyone s interested, here was our take on it over a World Climate Rerport:
Arctic Ice “Tipping Point” Rejected.
Seems an Arctic ice tipping point is a favorite story of John Holdren.
-Chip
The evaporation and resulting fog/clouds really throw a spanner into the works. Evaporation removes a lot of heat from the ocean. The fog/clouds reflect heat back to space but they also act as insulation. I haven’t seen a trustworthy paper that describes this yet. I would dearly love to see someone actually try to measure the heat flux.
I remember looking out over the frozen arctic ocean and seeing a fog bank rising straight up thousands of feet into the sky. I had never seen anything like it. The met tech explained that it was caused by a patch of open water.
There are one or two scientists whose judgment I trust when it comes to things arctic. The rest only spend relatively brief periods if they go there at all. It is really easy to concoct plausible sounding theories from the comfort of a desk down south but if you’ve never spent whole years up north, you won’t have a working BS filter based on lived reality. My favorite example is the number of people who seem to think that the arctic sea ice melts from the top down. That’s simply not true. By the time you see puddles, the ice is 1/10 as thick (or less) as it was when the sun came up. If you haven’t spent time up north actually measuring ice thickness by boring holes, you won’t know that and your theories will be bunk.
My other favorite example of scientific cluelessness: Talk to an Eskimo (I’m being deliberately non-PC, they prefer to be called Inuit) about polar bears. You won’t get the same story you get from the scientists. I’m betting the indigenous are right and the scientists are wrong. </rant> (but I could go on)
It should be noted that the absence of a “tipping point” , in which a loss of sea in a single summer, would cause permanent disappearance of the ice, independent of climate trends, does not imply that ice free summers in the Arctic will not happen. According to the Science Daily news story on the article, where the authors were interviewed:
The researchers underline that their results do not question the dramatic loss of Arctic sea ice or its relation to anthropogenic climate change. “If we don’t slow down global warming extensively, we will lose the summer sea-ice cover in the Arctic within a few decades,” says Tietsche. “Our research shows that the speed of sea-ice loss is closely coupled to the speed of global warming. We think that it’s important to know that we can still do something about slowing down or possibly even stopping the loss of the sea-ice cover.”
The authors are saying that if the earth gets cooler, the summer arctic sea ice will reappear. They are not saying it won’t disappear if the climate gets warmer.
Climate boffins never seem to think these things through. There is practically no sun during the arctic winter and because of the high angle of incidence not much in the summer either. As well, water reflects sunlight quite well at high angles of incidence. So the bottom line is albedo doesn’t mean a whole lot above the arctic circle.
What DOES matter a lot is that ice is a decent insulator and prevents the liquid ocean underneath from cooling by radiation and convection. So the positive feedback that the climate boffins imagine is actually a negative feedback. That should sound familiar. They imagine that surface heating caused by increased CO2 has a positive feedback effect through the creation of more water vapor while that too is actually a negative feedback due to increased evaporation, convection of the energy upwards in latent heat of vaporization, and release at altitude when a cloud forms which the raises albedo in lower latitudes where albedo really matters a lot.
These runaway warming narratives get tiring and make one wonder how these people ever passed any kind of physical science course in their sorry lives.
Basically they found out that open water freezes in dark and -30Ā°C.
real talk translation of this story: Hey, you know that stupid, made up thing that’s never going to happen? Just in case it somehow does happen don’t worry about it because that entire idea of a “tipping point” is just another stupid, made up thing that’s never going to happen.
While being quite ignorant of the details, this is something I have been saying ever since someone here (much more knowledgeable than myself) pointed out the possibility.
What I find ridiculous is that the idea makes so much sense, and yet the warmists have completely ignored the possibility as it does not ‘feed their monster’.
Spare a thought for the aide that has to pass on this information to the hitherto misinformed Prince Charles. This will only serve to reinforce his misgivings over the likely outcome of his five year prognosis.
A lesson in the venality of grant chasing scientists, politicians and sycophantic courtiers and advisors. At his age the lesson should however have been unnecessary.
Anthony,
In the whole history of this planet, has it ever overheated to what these guys are exaggerating too?
I do have to give credit to a very active imagination through the whole climate science community. Unfortunately, they also effect government policies.
An ice-free arctic will absorb so much more sunlight in the winter. Oh…there is no sunlight in the winter. Well, maybe the lost energy will keep the Arctic ice-free all the time.
Doesn’t an ice free Arctic summer….
…mean the weather is improving
I was going to comment that lack of arctic ice has exactly the opposite effect – a negative feedback.
1. open water reflectance increases as the angle of incidence decreases – the arctic sun is low in the sky to begin with and what little sunlight is left in the winter is reflected just as well off water as off of ice
2. there is very little sun above the arctic circle to reflect in the first place, even in the summer, and in the winter it diminishes to near zero insolation so between this and high reflectance at low angle of incidence albedo really doesn’t mean much near and above the arctic circle
3. ice is a good insulator and when it covers a body of water it prevents that body of water from giving up heat by radiation and reflection. In the arctic winter if there’s no ice that water will be cooling down like a mofo and there won’t be no ice for very long.
In short, arctic ice melt has a negative feedback with it that limits further ice melt. That’s a contributing factor for why the earth has gone through many ice ages but has never experienced a runaway greenhouse in all its billions of years of history.
This narrative about positive feedbacks from the climate boffins is a familiar refrain. A higher level of CO2 in and of itselt does nothing but add a small amount of very beneficial warming – extending growing seasons, making plants grow faster, and use less water while they’re doing it. Everyone knows this so so the climate boffins invented a positive feedback where more CO2 makes it a little warmer and the little more warmth puts more water vapor into the atmosphere which makes it warmer still and starts a runaway greenhouse. This simply doesn’t happen in the real world, has never happened, and never will happen so long as the earth remains a water world. Increased warmth results in increased evaporation which convection carries upward along with a huge amount of latent heat of vaporization. Adiabatic lapse rate causes the water vapor to condense a thousand or more feet above the ground where it releases all that heat upon condensation. The heat is thus swiftly removed from the surface and carried upward where it has an easier path out to the cold of space. Adding negative feedback upon negative feedback when the heat is released by condensation a cloud is formed and if it’s during the daytime (clouds tend to form in the afternoon which is why afternoon/evening thunderstorms are the strongest and most frequent) the cloud is highly reflective and blocks the strong afternoon sunlight from ever reaching the surface.
Higher atmospheric CO2 is actually a great benefit so when it comes to fossil fuels – burn baby burn!
Models are useless to confirm or refute an hypothesis as they do not have predictive power and do not take into account how the climate mechanisms change when the Earth has a surplus or lack of energy.
Worryingly the Earth seems to dispose of surplus energy easily via heat transport from equator to poles, but is not good at conserving energy at times of scarcity. It seems in this case it can only maintain temperatures suitable for life by sacrificing territory to extra polar ice, particularly in the NH. That’s why ice-ages are common events and warm climate optimums are relatively rare.
Here’s hoping the sun decides to wake up soon!
corrections added:
I was going to comment that lack of arctic ice has exactly the opposite effect – a negative feedback. But others already did so the points are repetitious but they deserve repeating.
1. open water reflectance increases as the angle of incidence decreases – the arctic sun is low in the sky to begin with and what little sunlight is left in the winter is reflected just as well off water as off of ice
2. there is very little sun above the arctic circle to reflect in the first place, even in the summer, and in the winter it diminishes to near zero insolation so between this and high reflectance at low angle of incidence albedo really doesn’t mean much near and above the arctic circle
3. ice is a good insulator and when it covers a body of water it prevents that body of water from giving up heat by radiation, evaporation, and convection. In the arctic winter if there’s no ice that water will be cooling down like a mofo and there won’t be no ice for very long.
In short, arctic ice melt has a negative feedback with it that limits further ice melt. That’s a contributing factor for why the earth has gone through many ice ages but has never experienced a runaway greenhouse in all its billions of years of history.
This narrative about positive feedbacks associated with arctic ice melt is a familiar refrain from the climate boffins. A higher level of CO2 in and of itselt does nothing but add a small amount of very beneficial surface warming – extending growing seasons, making plants grow faster, and use less water while they’re doing it. Everyone knows this so the climate boffins invented a positive feedback where more CO2 makes it a little warmer and the little more warmth puts more water vapor into the atmosphere which makes it warmer still and starts a runaway greenhouse. This simply doesn’t happen in the real world, has never happened, and never will happen so long as the earth remains a water world. Increased warmth results in increased evaporation which convection carries upward along with a huge amount of what’s called latent heat of vaporization. Latent means it won’t register on a thermometer. Adiabatic lapse rate causes the water vapor to condense a thousand or more feet above the ground where it releases all that latent heat upon condensation. The heat is thus swiftly removed from the surface and carried upward where it has an easier path out to the cold of space from the higher altitude. Adding negative feedback upon negative feedback when the heat is released by condensation a cloud is formed and if it’s during the daytime (clouds tend to form in the afternoon which is why afternoon/evening thunderstorms are the strongest and most frequent) the cloud is highly reflective and blocks the strong afternoon sunlight from ever reaching the surface.
Higher atmospheric CO2 is actually a great benefit so when it comes to fossil fuels – burn baby burn!
Claude Harvey says:
February 9, 2011 at 11:37 am
“….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?”
Best anti AGW comment and analogy of the day.
phoenix ice?
Joe Lalonde
February 9, 2011 at 2:00 pm
The Holocene Climatic Optimum (AKA Atlantic Period) was much warmer and more humid. The temps were from 3 to 6 degrees warmer then today, depending who you talk to, though the greenies are doing their best to make the science go away. This was a time of great advancement in human civilization. Seas were 5 to 9 meters higher also, which probably gives a good maximum sea height, given the closure of the tethis (Mediterranean) and the blockage caused by the ismeth of Panama, coupled with the thermal isolation of antarctica.
Urederra
February 9, 2011 at 3:13 pm
phoenix ice?
###
Hockey was very popular when I was a kid in the late 60’s early 70’s. I loved the Roadrunners š
Some posters here have mocked the conclusion that and ice-free arctic should recover its icecap. But this is a step in the right direction.
One of the central planks of warmist theory is the assumption of unstable equilibrium. The smaller-icecap/lower-albedo argument has a grain of truth, and the claim that this leads to irreversible warming has not yet been debunked.
The loathesome expression “tipping point”, with its image of a capsizing ship, struck fear into many viewers of An Inconvenient Truth: Mister Gore has consummate propaganda skills (we should grudgingly admit) and the “tipping point” expression is dazzlingly effective. If this AGU paper helps demolish the “tipping point” fallacy, then great!
No GCM model is required to come to the conclusions of this paper.
Annually averaged solar insolation in the Arctic is about 2 kWhr/m^2/day, or about 83 W/m^2. Open water at 276 K has an IR emissivity of almost 1, and emits about 329 W/m^2. A clear sky radiates back an empirically measured amount of about P = 8.8E-13*T^5.85 = 167 W/m^2. The net IR emission from open water is 329 – 167 = 162 W/m^2.
Therefore, open ocean will emit, on average, about 79 W/m^2 more energy than it will absorb from solar insolation. This is a low estimate, since all of the solar insolation is assumed to be absorbed, but this is not true because of the low angle of the sun above the horizon even at peak summer insolation.
Salute!
Can’t find the reference, but seems like in the 70’s or late 60’s someone ( might have been in Scientific American) postulated that the great continental glaciers came about because the Arctic had less ice and more water to form snowstorms further south year after year. Sorta like we’ve seen in Great Britain and to some extent in North America these past few years.
The persistent snow cover reflected more sunlight and global cooling became strong enough for those giant glaciers to form.
Anybody else remember this?
Pat sends…
Ugh GCMs.
Can’t we ge a study that uses empirical measurements as proof? Why is hard data so out of fashion? I guess it’s easier to sit at a desk with your C++ book and color graphs that actually picking up a thermometer.
Brent Hargreaves says:
February 9, 2011 at 3:52 pm
“Some posters here have mocked the conclusion that and ice-free arctic should recover its icecap. But this is a step in the right direction………..
If this AGU paper helps demolish the ātipping pointā fallacy, then great!”
======================================================
Yes, of course, you are correct, but its a bit frustrating for some. Many of the comments here illustrate how far ahead of the curve skeptics are in this matter. There never was a tipping point to be considered. The albedo of the arctic has always been overstated. Nature has in place self regulating mechanisms. And water will turn to ice in freezing temperatures. I’ve been stating for quite some time that the arctic isn’t very relevant to the GW discussion, of course, others will probably disagree, but this paper would buttress my point of view. Ice comes and goes from that region by many causations. But if the ice were to totally disappear, nothing would happen and likely in short order, the ice would reappear. Man would forget and we’d drill ice cores again and pretend they hold some sequential information. “Oh look! Here’s some 3000 y/o CO2!!! This must mean…….”…..sigh
This is a very interesting model run, but given how AGW skeptics put little credibility in IPCC AR-4 model, I can hardly see how they would think much of the outcome of this model simulation.
Also of course, given how no true “tipping point” can ever be accurately predicted or modelled before it occurs, it is not surprizing that this simulation finds no tipping point in Arctic Sea ice.
Two additional interesting points– this model run is based on the assumption of AGW, and so of course must be rejected out of hand by AGW skeptics. And secondly, the run of this model assumes that the heat loss from the open water will simply go right out the TOA, without any consideration of other effects from the extra fall and winter heat in the Arctic. Others studies have shown substantial effects from that heat being released in the autumn and winter that most significantly include changes in atmospheric circulation patterns in the entire N. Hemisphere and hence a change in the climate of the Arctic, which this study ignores. See for example:
http://www.arctic.noaa.gov/future/docs/ArcticAND_Globe.pdf
http://www.arctic.noaa.gov/future/heat.html
http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0870.2009.00421.x/full
http://www.jamstec.go.jp/frsgc/research/d2/masayo.ogi/09056-galley-proof.pdf
So, while these model runs, might or might not be accurate to what might happen to the arctic sea ice under assumed AGW, why should AGW skeptics care as they either don’t think AGW is happening, or certainly don’t trust the IPCC AR-4 model this study was based on. Either way, it is based on the assumption in this study that you could have that much heat being released from open water in the Arctic during the fall and winter without significantly affecting global circulation patterns (as indicated in other studies). And most importantly, since “tipping points” are by definition, not predictable by any model, the fact that this model run didn’t find any, isn’t too terribly surprizing.
Wow! R. Gates has a bad hair day.
The science page of Deutschlandradio, one of the big German radio stations, also ran this paper http://www.dradio.de/dlf/sendungen/forschak/1382801/ .
When it comes to CAGW this site is total propaganda. No matter what research it is always “worse than we thought”.
Now this time they admit it might be not as worse as thought.
Did we reach a tipping point here?
R. Gates says:
February 9, 2011 at 4:31 pm
“So, while these model runs, might or might not be accurate to what might happen to the arctic sea ice under assumed AGW, why should AGW skeptics care as they either donāt think AGW is happening, or certainly donāt trust the IPCC AR-4 model this study was based on.”
========================================================
Because we know the IPCC AR-4 is an extreme model with extreme assumptions. So, this study suggests that even if extreme conditions existed, the self-corrective mechanisms would still prevail. We all knew this already, but many of us are glad to see some “scientists” suddenly realize this. Maybe they’ll catch up……..in a few decades.
Additionally, the way I read it, it wasn’t dependent upon AGW, or even GW. But simply assumed an ice free arctic as a starting point for the run.
Don’t they mean hysteric threshold behavior ?
Dave Springer says:
February 9, 2011 at 1:06 pm
Climate boffins never seem to think these things through…
Please define the pejorative term “climate boffins”.
It certainly doesn’t apply to S. Tietsche, D. Notz, J. H. Jungclaus, and J. Marotzke, who ran the climate models and came up with the result showing there is no “tipping point” for Arctic Ice, where loss of ice is unrecoverable. Without this result, there is no quantitative way to tell. The hypothesis of the existence of a tipping point on the part of some climate scientists was wrong, but that doesn’t prove they haven’t thought something through. It only shows that their judgement about the strength of summertime warming, versus wintertime cooling was wrong.
R GAtes says:
>>
This is a very interesting model run, but given how AGW skeptics put little credibility in IPCC AR-4 model, I can hardly see how they would think much of the outcome of this model simulation.
>>
Correct, most skeptics would reject the whole idea as unproven. The point is what it shows to those who “believe”.
>>
Also of course, given how no true ātipping pointā can ever be accurately predicted or modelled before it occurs, it is not surprizing that this simulation finds no tipping point in Arctic Sea ice.
>>
Why can’t a simulation simulate a tipping point?
Or do you just mean no climate events can be predicted before they happen and no model will ever get anything right?
Mr. R Gates,
This heat you speak of that is being ‘released’ is coming from where?
This heat that was ‘released’ goes where?
Since the atmosphere does little to heat the oceans, in the scenario of released heat, the net heat content of the planet should go down due to the warmer air radiating heat into space.
Scott Covert says:
February 9, 2011 at 4:20 pm
Ugh GCMs.
Canāt we ge a study that uses empirical measurements as proof? Why is hard data so out of fashion? I guess itās easier to sit at a desk with your C++ book and color graphs that actually picking up a thermometer.
===
Yes but almost anyone can read a thermometer. You need esoteric code and massively expensive hardware to generate a priesthood that holds all secret knowledge and can “explain” it simply to the surfs, in return for their surfdom and lots more money.
Credibility of AGU releasing such papers under a cloud – credibility gap widens.
Of course, this wonāt mean that Lindzen & Choi will cease to be a part of the denialist canon, to be trotted out every now and again in lists of papers skeptical of āman-madeā global warming and used to confuse an unfamiliar public; but it will mean that the warmists can quickly point out that itās not quite what itās cracked up to be and shut us deniers up about it for a while. This is very unfortunate, and frankly itās a bit of a blow to the denialist credentials of the American Geophysical Union, publishers of Geophysical Research Letters and Journal of Geophysical Research ā Atmospheres, the journal that hosted a paper by our friends McLean, de Freitas & Carter that became another denialist touchstone and which, together with Lindzen & Choi, made AGU the publisher of fully two-thirds of the peer-reviewed denial of 2009. Sadly, the McLean et al. paper, too, has lately been shown to be bollocks. [As an aside ā itās interesting to consider the two papers together, because while McLean et al. purported to show that ENSO, a phenomenon of tropical origin, has been exporting heat to the rest of the planet so efficiently itās been responsible for almost all global temperature change since 1958, Lindzen & Choi implicitly assumed that tropical heat hasnāt been exported anywhere except into space. And the Friends of Science claim that temperature change is all because of the sun. Canāt accuse us deniers of being inconsistentā¦]
http://friendsofginandtonic.org/files/b78f644320e6cc9c1d8e3e1ce2b17432-137.html
R. |Gates 4:31
It is precisely because they used IPCC’s model with its biases and exaggerations that the finding is so solid. They also used an increase of 2C when empirically from the past century and a half it has been 0.7C, ie 0.5C per century (don’t forget the high priests have admitted that there has been no statistical warming since 1995, over a sixth of a century, and many of the faithful have even granted that we might have a cooling for another couple of decades).
Skeptics who bemoan yet another use of a model should understand that the Max Planck Institute deliberately used an accepted model that had been used to show the death spiral. The researchers chose a powerful strategy in using this worn model. They may privately believe that the reality will be even more ice growth in the arctic.
Another point touched on by others: I can’t believe that real scientists would not take into consideration a) the low angle of incidence where, even if there was no large reflected component, and the filtratation of sunlight by the effectively greatly increased air thickness could be ignored, the incident radiant energy is sine 20 x radiant energy at the equator.
So, the summer ice melts and the sun heats the cold Arctic waters. 24 hours a day, sort of. For a few days. Then the sun, as seen from the Arctic, heads south, taking its warmth with it. And the Arctic Ocean, denuded of ice, is exposed to darkness and space and sort of thermodynamicky stuff. And the heat left in the water is lost to the atmosphere even tho CO2 does its best to keep it warm. But the CO2 can’t keep it warm because the ice is gone and is not there to provide insulation. And the water, instead of staying warm and making sure no ice ever forms again in the Arctic, freezes. And there is no feedback and warmistas face the spring with the task of reforging GIGO for their models. Reality bites.
@P.Solar You can’t explain anything to the “surfs” but the “serfs” can be made to understand. I know this because I are 1.
@psolar
A nice result. Debunking the notion of a `tipping point’ for arctic sea ice in the published literature is a very worthwhile thing to achieve.
“Dave Springer says:
February 9, 2011 at 3:08 pm
Increased warmth results in increased evaporation which convection carries upward along with a huge amount of whatās called latent heat of vaporization.”
This is very true. 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?
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”
There is now 1 positve feedback (arctic ice albedo)
but 3 negative feedbacks:
– heat and radiation loss of the open water finally to outer space
– evaporation causing increased cloud coverage further south, thus increasing albedo (and at much more improtant latitudes)
– increased snow at lower latitudes, again increasing albedo.
It doesn’t matter in this context what caused the sea ice to decrease for some time.
What matters is the size of these feedbacks, and as the authors come to the conclusion that any ice free arctic may recover within as little as 2 years, their combined effect should be strongly negative.
That blows one of the main scares and last straws of AGW out of the water.
We have seen expanding areas of open water in the Arctic summer since at least 1990. Most of the potential extra open water is already exposed to the summer sun. Because of the consistent sinusoidal pattern of Arctic melting and refreezing any additional exposure will likely occur between late August and the end of September when the Sun is circulating barely above the horizon and any additional effect beyond what has already transpired is likely to be marginal. Can anyone point me to some empirical observations that indicate that the projected scenario has been transpiring in the last two decades? I’ve had some difficulty locating it for myself.
A good example of the resilience of Arctic ice was shown be the recovery of ice thickness after the low areal extent of 2007. The average ice thickness actually continued to decline until 2008 but has now recovered to its long-term value. See mu analysis t:
http://www.climatedata.info/Impacts/Impacts/seaice.html
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.ā 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 hadnāt changed. In other words, the ice albedo feedback that most climate models predict will ultimately amplify global warming apparently hadnāt 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. āhigh reflectance at low angle of incidenceā The angle of incidence is measured from the normal so it should be āhigh reflectance at high angle of incidenceā”
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 ātipping pointā) …
P. Solar says:
February 9, 2011 at 5:44 pm
“Donāt 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.
“Letās say the arctic ice caps melts, what is the worst that can happen? Ice that is already in the ocean wonāt rise the sea level, so whatās 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 whatās already known: that the Arctic is āunlikelyā 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 doā¦
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 pleaseā¦:)
_____
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 donāt recall any GW theorists positing that the Arctic would be ice-free year-round due to global warming. The GRL paper simply states whatās already known: that the Arctic is āunlikelyā 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.
@ 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.