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Yvan Dutil

Well, as a scientist, you don't want to overestimate. If you overestimate,the accusation of exaggerating will follow immediately and your message will be lost. From a political point of view, conservatism is the safest path.

Kevin McKinney

Well-said, Neven--again.

I think that the statement you highlight--"There is very high confidence that climate models realistically simulate the annual cycle of Arctic sea ice extent, and there is high confidence that they realistically simulate the trend in Arctic sea ice extent over the past decades"--is correct as stated.

That is, the modeling of the annual cycle is pretty accurate, and the pasttrend as modeled is too--the really big discrepancies are for the last few years only.

The trouble is, of course, that once again we have a statement that is scientifically correct and rather conservative--and that fails to capture the apparent gravity of the situation in which we find ourselves.

Hans Verbeek

I'm still reading the part about Northern Hemisphere snowcover.

'Till lured by sirens' cry.'

Al Rodger

As the IPCC is but a review of the literature, I thought it would be useful to have links to the references from Chapter 12, section 4.6.1

Boe et al 2009a

Massonnet et al., 2012;

Stroeve et al., 2012

Wang and Overland, 2009

Wang and Overland, 2012

Zhang, 2010b,

Massonnet et al., 2012
(Anonymous Referee #2.
http://www.the-cryosphere-discuss.net/6/C1297/2012/tcd-6-C1297-2012.pdf )


Lets worry about crime, jobs, economy etc please instead of stupid ice.



As a scientist you don't want to underestimate either. You lose credibility equally fast either way. Clearly the models are divergent from reality. Reality wins every time.

As Neven points out, the consequences of getting this wrong are of losing the earth we know. Sadly, that is now a done deal. The locked in rates of change are too great. The inertia in the now moving system is so huge, that no amount of effort on our parts can stop it.

About the only thing left that could change it is an eruption of a super volcano like Yellowstone. And that would be an unimaginable calamity, and even that likely wouldn't be enough.

Still our systems are running us, and are running out of control. In the rush for tight oil, the money is lucrative, so the rush is on faster than infrastructure can keep up. As a result, they are flaring much of the natural gas. From a climate perspective that is insane. Our financial systems don't allow for any other answers. And this insanity is repeated throughout all if our systems.

Likewise our political systems respond after the act, not before. They are lagging indicators of what has already happened. They respond to entrenched interests. Unless and until those entrenched interests are convinced of what they might see as direct and immediate harm, they will not change.

Climate lags our actions as well, but once it begins moving the inertia is so great that it will not be stopped.

At this point, our best hopes are perhaps that we can see and understand the problem well enough that we can salvage some remnant of what once was as the system rolls over in one of the great changes in the history of life and as we enter not just a new chapter, and not even just a new volume, but a new book in the story of life on earth.

And even here, the practice of science as a part of society is far too slow. We humans seem only to accept such changes on career or decadal scales. And if the changes that are needed as revealed by the science are painful or costly, the inbuilt resistance of the financial and political systems are so great that we seem only to change when no other answer is possible.

Aaron Lewis

The guys that have underestimated global warming, time and time again are still the "experts" that publish in Science and Nature. And every time that they publish another article saying, "We underestimated!" makes them all the more the experts.

dominik lenné

The IPCC statement might be correct, say: still not completely false - but a note on the recent deviation is the least to expect.
Then, how about ice volume?
We wait for the first model to get the accelerated melting right in the middle of its probability field.
The interesting question is, where the main differences lie between models and reality. Models failed, but where exactly? Is it ocean currents? Is it atmospheric heat transport? Is it pressure distribution, cloud cover and insolation? Is it thicker snow cover with subsequent slowing down of winter ice thickness growth rate?
So many questions and no comprehensive emission certificate system in sight...



Speaking as a scientist, I feel that fear of exaggeration is holding back scientists from fulfilling their role of speaking bluntly to policy makers. This is a phenomenon that has been dubbed “erring on the side of least drama” by Naomi Oreskes and her colleagues. http://www.sciencedirect.com/science/article/pii/S0959378012001215

Another recent analysis also concluded that " if the consensus estimates such as those from the IPCC are wrong, it is because the physical reality is significantly more ominous than has been widely recognized to date". http://www.skepticalscience.com/freudenburg.html
I am therefore in agreement with the views of Prof. Emmanuel, quoted by Neven in his piece above, that this bias towards caution is inhibiting proper risk assessment, with crucial consequences for the formation of appropriate policy.

It is entirely rational to be more concerned about uncertainty towards only one side of a projection, for example companies will often hedge their decisions so as to minimise the risk of going bust, even at the expense of the possibility of making the largest profits.
To asses the risk associated with a particular event we must know first of all the probability of that event occurring (i.e. how likely is it that the Arctic will be seasonally ice free by 2020) and calculate a measure of the harm/hazard if this event were it to occur (i.e. a rapid acceleration of climate change). Risk is then calculated as the product of the probability and size of the hazard. Even if the probability of an ice free arctic was low, since the hazard is huge it might well be that if properly informed policy makers would decide that the risk is large enough to take action to avoid that possibility.

Human beings tend to be risk averse on an everyday basis, we reveal this for example by taking out home or life insurance policies. Given that we only have one planet to live on it seems to me highly prudent to be even more risk averse when it comes to changing its climate, but this requires that we are properly informed of the risks- even of extremely unlikely events.

It is my view that by erring on the side of least drama, scientists are cowing under the fear of attacks from sceptics (which we have to recognise will come no matter what we say) and are failing to give policy makers an accurate picture of low probability but high hazard events.

Consensus reports whilst useful for highlighting areas of uncertainty, due to their extreme caution, are therefore hindering rather than helping us forming appropriate policies.

dominik lenné

@Boa05att: Yes, this is what has not been done in Fukushima, where the risk of a big earthquake had been calculated as once in 1000 years or so, which seem small at first glance , but yielding 1/30 within nominal reactor lifetime, which is very big, taking into account the potential (and then real) damage.

Kevin McKinney

"Lets worry about crime, jobs, economy etc please instead of stupid ice."

Or stupid comments. Scott, if you aren't just a drive-by, and if you wish to learn why your comment was stupid, you are in the right place.

Yvan Dutil

I am a scientist and I am very familiar with the political process. Your are perfectly right about the way risk should be managed. Very basic classical risk management technique would have tells you 20 years ago to take action to reduce greenhouse gases. Also, the same basic management tools would have tell you that that the best strategy would be to plan something closer to the worst case than the middle case.

However, apart of been risk adverse humans have very much trouble to NOT discount the future. Many people dot care what will happen in a 20 years time frame, even less in an 100 years one. And many more, are wondering how they will close to month. We are just psychologically blind to that type of risks.

Politics only reflect that.

The secret hope of many people like me who work in energy is that we will exhaust the fossils fuel before it is too late. Otherwise, I don't we could manage this issue.


Pusillanimous? It's not about science, the IPCC are in the grip of the the Patty Hearst syndrome (Euro: Stockholm Syndrome).

Summer sea ice 2012 too slippery for CMIP5? That's models telling us bumblebees can't fly:

"Tou d'abord poussé par ce qui fait en aviation, j'ai appliqué aux insectes les lois de la résistance de l'air, et je suis arrivé avec M. Sainte-Lague a cette conclusion que leur vol est impossible.
... Antoine Magnan Le Vol des Insectes (1934)


Mummified trees on Ellesmere? These might or might not be the same ones:


This was Joel Barker's AGU poster from AGU Dec 2010. Nothing published yet as far as I can see ... two full years and counting.

"The existence of fossil forests at high latitudes above modern treeline provides an insight into environmental conditions in deep time and may provide an indication of high latitude ecosystem response to future global warming. By identifying the flora, which comprise a fossil forest, the general environmental conditions favoring the growth of these species may be inferred for that area at a given time. Further, mummified paleoforests i.e., those paleoforests where the flora is not silicified but instead preserved in a desiccated state .

Here, we report the existence and characteristics of a mummified [ie not petrified] paleoforest deposit on Ellesmere Island, Canada. This deposit is the most northerly reported to date (81.5°N) in the Canadian archipelago and exhibits a floral composition that differs from that of deposits located further south e.g., the Geodetic Hills on Axel Heiberg Island. The existence of this deposit permits both an extension of the paleo-arctic treeline to a more northern latitude and the environmental conditions at these locations during periods when the Earth was warmer than at present."



It's such a relief to me that you have taken up this issue.

Can I hope that you can do something to engage

1. The European Commission?

2. The BBC?

The reply to BlueSky from Connie Hildegaard, the European Commissioner for Climate Action, showed that the Commission are following the IPCC slavishly and are in denial about the seriousness of climate change. I hope you can highlight their failings.

The BBC - as a public body - should tell us the truth. They are also in denial. My TweetsToTheBeeb and letters via my MP are easily ignored. You (rightly) have the status to make a difference. I hope you can put the BBC on your list for action.

Thank you.
Thank you.
Thank you.


It is me who has to thank you, Geoff. I knew I had to do something with AR5, but was lazy, until I read your blog post. That kicked the whole thing off.

However, I can't do more at the moment than try and write blog posts (there's about five or six still waiting to be written, not least of all about Larry Hamilton's recent work). But I'll keep stressing the importance of what's going on in and around the Arctic.

I think there are a couple of events, notably in the UK and Russia, that qualify as winter weirdness, so I'm going to try and do a post on that in coming days.


>"But just don't go and say "There is very high confidence that climate models realistically simulate the annual cycle of Arctic sea ice extent". Because I don't think there is, really."

Come on Neven, don't quote the wrong bit.

There is very high confidence that climate models realistically simulate the annual cycle. Just look at any model and you will see that the ice peaks and troughs at the right time of year. It would be very alarming if they didn't so this isn't much of a claim but is correct.

They are only claiming:
"high confidence that they realistically simulate the trend in Arctic sea ice extent over the past decades. {9.4.3}."

You are showing that to be rather suspect.

Should we be commenting that they are using weasel words where 'past decades' does not include the current decade? Or is high confidence a lower standard than a lay-person might think? Or is it just plain wrong?

What would best reflect the situation? Perhaps adding "but fail to anticipate the speed of decline in the last decade" would properly reflect the situation.

Should we expect them to rubbish the models if that is what is called for? That possibly creates interesting political questions.


Come on Neven, don't quote the wrong bit.

* slaps forehead *

You're absolutely right, crandles. Imagine models not getting the annual cycle right ('...and therefore we project an extent of 20 million square km2 in June 2050'). ;-)

Changed that bit. Thanks.

Should we be commenting that they are using weasel words where 'past decades' does not include the current decade?

If I remember the Stroeve paper correctly, it said that the models that got the past trend right, had a much lower SIE to start with. I'll look it up. Found that interesting at the time.


Neven wrote:

that qualify as winter weirdness

Weirdness-lovers shouldn't miss this shot:

It's a view from the Little Diomede island towards Ratmatov or the Big Diomede as the Americans use to call it.

As you all can see, there is surprisingly a large stroke of open water between the two islands.

Actually, the space between the two islands was completely frozen solid last week. Thus there must have been something as like melt there ...



"The secret hope of many people like me who work in energy is that we will exhaust the fossils fuel before it is too late. Otherwise, I don't we could manage this issue."

If I've understood it right the energy companies already have in their inventories several times over the amount of hydrocarbons we safely can burn and still remain under the 2C threshold...


Don't take the septics too seriously Neven, we need people like you around for much longer!


Let me see if I can summarize in my layman's terms:

1) The Arctic ice sheet has been melting away at an INCREASING RATE over the last 30 years, and especially over the last 10 years.

2) We have INCREASING POSITIVE feedback effects from (a)melting tundra, (b) melting melting hydrates in the oceans, (c) lower reflectivity (albedo) of the Arctic itself, not to mention its next door neighbor Greenland, (d) increased fires in northern Asia and North America which will further exacerbate albedo, (e) LESS ICE AREA to reflect sun in the Arctic...and thus allow that nice dark water to absorb more and more sun.

How in God's green earth....given #1 and #2 above...can someone NOT think that the Arctic melting is LIKELY TO INCREASE ITS RATE OF MELTING over the coming years is beyond me.

Two things will change their minds QUICKLY: (1) another bad year of melting like we had last year in the Arctic, (2) a bad year of melting on Greenland with a week or two of melting like we had in the mid summer last year (which will blow up the idea of that happening every 150 years going forward).

Maybe THAT will get their attention. Pure math and statistics is obviously not enough.


Buddy asked:

can someone not think that the Arctic melting is likely to increase its rate of melting over the coming years is beyond me.

No need to shout, lower case just does fine the job.

First part of the answer is, in order "not" to think you still must be able to think.
Now, the quintessense of denialism is the denialist sticks to a certain axioma to which any form of contradiction is strickly forbidden. "Vietato di razionalizzare" - any kind of reasoning is forbidden. Happens to commun people as well as high ranked professors.

The second part of the answer is the 'Après moi le déluge' mentality in certain "high" educational and industrial circles.

That kind of people assumes, just as did centuries ago Madame de Pompadour and King Louis XV that the benefits still will hold during their lifetime and the problems will be the preoccupations of future generations.

Or, to put it in plain American, "who cares?".


Kris said: "..the quintessence of denialism is the denialists sticks to a certain axiom to which any form of contradiction is strictly forbidden."

I was addressing the "cautiousness" of AR5....NOT (emphasis added) denialists.

The thrust of Nevin's article (and I agree with him) is that the scientists appear to be taking a stance that is too conservative. There are "risks" to being too conservative, just as there are risks to taking a stance that is too aggressive.


I'm on the same page as Buddy here. Note the 2012 and 2013 Arctic Ocean melt seasons -- as well as record land snow loss and record melt on Greenland -- didn't happen as far as the IPCC Sept 2013 report is concerned. Maybe they will get to 2012 by 2017. In other words, even after the climate has hit bottom, IPCC will still be prattling on about the good old days (or general climate model scenarios for 2100).

As Al Rodger notes, the IPCC is nothing but a literature review, taken down a notch for educated non-scientists, together with 3 futuristic scenario computations. Note every last climate science journal article is required to provide an introductory and discussion section. These are mini-reviews of moderately limited scope but often quite good. The number of substantial research articles per year is something like 2000, or 6 a day. Suppose there are 40 distinct active topics (sea ice, Antarctic grounding lines, cow belches, ...). Then a literature review is provided every 4 hours around the clock and every active topic is reviewed every week.

However Sept 2013 IPCC will not acknowledge these last 2200 papers and their mini-reviews nor routine observational events of the preceding 14 months (eg Mauna Loa methane). It is obvious that the Nov 2012 "draft" is the final document, modulo the scenario computations. Watch people do line-by-line comparisons when the final come out.

The IPCC was very traumatized by the Himalayan glacier kerfluffle. Now they are on the defensive, playing it ultra-safe rather than just pitching the ball over the center of the plate. Big tent to accommodate paid skeptics: anyone -- including the economics grad school dropout -- can register as expert reviewer (just as Monckton got official credentials at Doha). They could have used easily checked minimal criteria such as 3 publications in scientific journals of impact factor 3 or higher in the last 5 years but wanted to be "inclusive".

Yet Geoff is quite right about EU and BBC deference to the IPCC -- what else is out there? The lamestream media has lost capacity to sort fact from fiction; with corporate advertising at the heart of their business model, always the exasperating quote from Cato neutering every shocking development.

So while I can applaud Geoff for his letters, Nevin for his blog, Randall for his freeway signs and boo the IPCC and GCM modelers, the fact is, we're way past the turning point already yet still oblivious. Nothing much will happen until we've really hit every day bottom. At which point the situation will take centuries to remediate.


Those trees burned by early Ellesmere explorers? I traced these burnable (though lignified) mummified trees down to the 1881 US Army Calvary's Greeley Expedition to Sgt. Brainerd's find on the Judge Daly peninsula a bit south of Cape Baird. However the Greeley expedition (whose diaries are now online) used a coal seam near camp for fuel rather than these trees or the copious shore driftwood from Siberia. This location is distinct from the Barker site though still in Quttinirpaaq National Park. Barker's protestations notwithstanding, this sounds very similar to the Axel Heiberg Geodetic Hills site investigated in 1987 by JE Francis. The state of mummified trees and forest litter there was likewise extraordinary, redwoods (Metasequoia) being the dominant large tree there.

Folks interested in high Arctic paleoclimate ecology can find the research history by looking at the 38 forward cites at Google Scholar for the title "A 50-Million-Year-Old Fossil Forest from Strathcona Fiord, Ellesmere Island, Arctic Canada: Evidence for a Warm Polar Climate".


George Phillies

Going up to the first graph here, some of those empirical fits are subject to empirical confirmation or falsification very soon. For example, the log fit shows a zero this coming summer. The next fit hits zero two years later. Etc.


If've I've understood chapter 11 of the draft report properly then they're claiming that:

"It is very likely that there will be continued loss of sea ice extent in the Arctic, decreases of snow cover, and reductions of permafrost at high latitudes of the Northern Hemisphere by 2016–2035. Using RCP4.5, Arctic sea ice area is projected to decrease by 28% for September"

And that this is with respect to the 1986-2005 average.

I might be mistaken, but if that is the case aren't we already well below that 28% reduction?


A-Team Said: "The lamestream media has lost capacity to sort fact from fiction; with corporate advertising at the heart of their business model, always the exasperating quote from Cato neutering every shocking development."

I'll keep this comment on the subject of Arctic ice, but your point about advertising is a VERY BROAD issue that has ramifications about our daily lives. Remember, we live on a "finite planet", which means there is no such thing as "sustainable long term growth". At some point we reach a point of "a sustainable LEVEL". Seven billion and counting is too many people for the earth to support for the long term.

Just like banking regulations after the Great Recession; just like tobacco regulations after decades of the industry lying; just like decades of the asbestos industry lying; just like the soda industry continues to lie about fructose today; just like the airline industry didn't change policies on protecting the cabin until after 9/11 (the first US hijacking was in the 1960's); just like the gun industry through the lobbyists like the NRA continues to drag their feet.....The force for change will have to be from the BOTTOM UP.

The change that will come will be forced by people like Nevin and the thousands of others that look at FACTS and DEMAND that the policy makers look at the FACTS and take appropriate action. The truth NEVER goes away....and the truth about the Arctic and climate change in general, is revealing itself one painful event after another...and one painful year after another.

People don't change until they HAVE TO. Another year or two of dramatic decrease in Arctic ice....another year or two of record setting melting on Greenland...will be needed for change to gain traction. This will be a long term issue....and the people in the oil, gas, and coal industries are NOT going to easily be moved....and neither are the politicians who are receiving money from them.


Would it not also be appropriate for the IPCC to say something like.

"In addition, we have high confidence that though the models do predict the past annual cycle of ice formation in the winter and thawing in the summer; we have very high confidence that the rate and extent of thawing due to changes in the atmosphere is not represented by the models to any significant degree, and that future projections of the rate and extent of thaw are only adequately represented by simple extrapolation models.

This is of vital importance to all peoples of the world, as the loss of the arctic ice poses such grave dangers to society, to agriculture, to climate, to weather and to war as to dwarf all other aspects of arctic modelling at this time.

We have high confidence that this is a crisis of global proportions that directly threatens all peoples of the world in the coming two decades."


Buddy - "another year or two of record setting melting on Greenland" ... I doubt something that is happening far from home that is not felt directly will trigger a change; only an empty supermarket at home, or a major river running dry close to home or anything else that is widely felt can cause a change in behavior - and only after the fact. There is no better driver in promoting fuel efficient cars then an increased price of fuel - warning of higher fuel prices just doesn't do the trick.


Sorry Sam, I don't agree on a lot of what you say. I think very high confidence re annual cycle is right.

I think the rate of change over past decades is represented by models to some degree but not quite well enough to gather high confidence. Some believe their models and some see divergence between models and reality.

Many wealthy people (who don't live on flood plains etc) won't be too badly affected for a couple of decades. Climate change is going to affect some people critically while others quite possibly living nearby are not so badly affected. So 'all peoples of the world' and within 'coming two decades' seem to be likely exaggerations that is unlikely to gather high confidence.

I am also completely sure you won't get very high confidence re "only adequately represented by simple extrapolation models".


I doubt something that is happening far from home that is not felt directly will trigger a change

Change happens slowly at first. Think about the tobacco industry. With each further "event"....with each additional corroborating study....change slowly gains momentum. You have seen visual signs in some noted meteorologists (Chad Meyers and Paul Douglas among them) that have changed their tune.

When "events happen" that aren't supposed to happen....wherever they happen...it changes some peoples mind.

Of course it would be much "easier" for people to understand IF that event happens close to them (just ask the residents of Newtown, Conn). But with each event, even those that are somewhat distant...change gains momentum.

And over the next 2 - 3 years....we will continue to see those events. And I think another bad year of Arctic ice, another bad year of Greenland melting, another bad year of fires in northern Asian and North America....the drumbeats of change will grow louder and louder.

Just as the NRA was "unmasked" by the recent events in Connecticut and shown to be nothing but a lobbyist for gun manufacturers.....events will continue to take place in nature that will give those that want to fight against climate change a little more momentum.

Kevin McKinney

"How in God's green earth....given #1 and #2 above...can someone NOT think that the Arctic melting is LIKELY TO INCREASE ITS RATE OF MELTING over the coming years is beyond me."

Well, there is more at work than the factors you (correctly) mention--heat advection into the Arctic being an important one. And that's a big enough unknown that it could overpower everything else, if I'm not mistaken.

But that said, you forgot to mention that the greenhouse forcing will clearly be continuing to increase for some considerable time, too.

Personally, I don't think we're going to see any sustained slowdown in melting. Hope I'm wrong, but...



Do you argue that if we apply some unspecified trend function the results of the CMIP5 models, it is possible to say

There is very high confidence that CMIP5 models realistically simulate the annual cycle of Arctic sea-ice extent

This means the models should get realistic results for the phase of the annual cycle and the amplitude of the annual cycle. Do they catch the slippage of maxima and minima? Is the asymmetric change of maximum and minimum values simulated correctly?

But in these arguments over semantics are we missing a more damaging possibility - that the draft of Chapter 9 is designed to confuse and paper over the failings of the CMIP5 models?

I hope not.

That would be very dangerous for the whole world.


Kevin McKinney:


I absolutely agree with you. And I hope we're BOTH wrong.

There are too many things that are "lining up" in favor of more...not less...warming over the next few years.

I mentioned the things I am familiar with...and the things that can be "seen" by someone like myself (someone who is NOT a scientist)....but someone who has taken the time to look at the facts and the science.

Conrad Schmidt

Why doesn't the IPCC use ice volume instead of ice extent? It seems to be smoother than extent and doesn't have the problem of distortion due to wind patterns. An all around better proxy for ice health. The cynic in me thinks it has to do with the fact that the graphs are much scarier. They show an ice free arctic before 2020.

Artful Dodger

Happy Holidays, Kevin!

(and please, DNFTT ;^)



I have been informed that the 2012 melting season will not feature in the final draft of AR5, for the simple fact that no peer-reviewed papers have dealt with it before the cut-off date, and that's because the cut-off date for submitted papers was 31 July 2012. A déjà-vu of 2007.

It's logical and insane at the same time.

Also there are some papers that have been ignored, such as Rampal 2011: IPCC climate models do not capture Arctic sea ice drift acceleration:
Consequences in terms of projected sea ice thinning and decline

Steve Bloom

A-team, I haven't checked the SOD paleo chapter, but I've paid close attention to paleo-Arctic research and it's been clear for years that a mid-Pliocene-like climate state (probably our best-case hope at this point) will feature boreal forest all the way up, and that Miocene-maximum warming (our reasonable hope IMO) will start seeing at least subtropical-like conditions in the Archipelago. Of course any of the latter, and any out-and-out tropical-like conditions in yet warmer climate states along the lines of the Eocene, will be very much "-like" because of the distinctly untropical insolation conditions. E.g. crocodiles are know to have been way north in the past, but since they're willing to scavenge for a living one can imagine them doing just fine over the winter. I suspect a lot more is known about warm-climate boreal biota, but I never read up on those details. Lots of ferns and redwoods along with a not very diverse land fauna would be my guess.

Having piqued my own curiosity, I'm off to have a look at that chapter.

Artful Dodger

We need to be clear about the terms used to define levels of confidence in the IPCC Uncertainty Guidance Note, namely:

Terminology	 	Chance Correct
Very high confidence 	At least 9 out of 10
High confidence 	About 8 out of 10
Medium confidence 	About 5 out of 10
Low  confidence 	About 2 out of 10 
Very low confidence 	Less than 1 out of 10


So using IPCC terminology, this is like saying there is up to a 10% chance that Summer sea ice levels will occur by JFM-2050.

I think that's a very reasonable estimate. I've previously estimated the first sea ice-free Arctic Winter to occur in the range 2036-2056.

But I don't need a paid holiday in Acapulco to say it. Maybe just a pick up the 10% tip ;)



I went to see the movie, "Chasing Ice," http://extremeicesurvey.org/ today. I highly recommend it on at least 2 levels:
1. The photography is absolutely astounding. James Balog and his crew take risks, endure boredom, equipment problems, and other difficulties to capture the most fantastic scenes of nature I have ever seen.
2. The implications of climate change come alive in their photography, especially the time-lapse movies. We can look at modeling, graphs, data, etc., but when the immensity of disappearing ice happens right before our eyes it startles and is very scary.
The latest photos are mostly 2009, 2010, and a few in 2011 so they don't show the effects of the 2012 melt season, so, I expect even "greater" things are in the "can" so to speak. Also, in the movie, the Ilulissat Glacier calving shown was attributed to the 2009 calving event.
It makes sense that the IPCC should also consider this documented evidence that is happening right before our eyes.


As reported at NOAA...if it looks like a rat, walks like a rat, and smells like a rat....it's usually a rat:


All those positive feedback effects are working against the Arctic and there is no reason to think they will back off in any significant way over the next several years.

Glenn Tamblyn

Unlesssomeone has seen anything to the contraryin AR5SOD, it lookslike the IPCC is ignoring PIOMAS. Fine,ther may not be any new papers associated with it, bet then howmany newpapers are attached to GISTMP, HadCRUT, RSS etc. Let alone NSIDC etc.

For some reason the IPCC authors of this section are ignoring volume. Which is the main game. If AR5 is published Sep 2013, it could be totally trumped by the SIE figures the same year - no way volume can continue on it's current trend without SIE crashing over the next 3 years. The IPCC might have egg on it's face for so wildly underestimating.

That said, although nobody wants the Arctic Sea Ice tobe vanishing,I can'tthink ofanything more dramatic to grab the public's attention. The MSM will love it. All showing graphs of extent crashing.

The Arctic may be the first canary-in-a-coalmine but it might also be a very loud screaming parrot as well.

It has something other facets of Climate Change don't have - visuals!

Kevin McKinney
Happy Holidays, Kevin!

(and please, DNFTT ;^)


And to you, Lodger... the tricky part is always "the wisdom to know the difference."

But the reminder is duly noted.

dominik lenné

Concerning volume: If it's not taken by IPCC (I did not read the draft and also, there will surely be modifications) then for the simple reason, that it cannot be measured directly and so any data have a pretty wide uncertainty bar and are open to attack. A very unsatisfactory situation for years now.
I propose herewith to invent cheap mass produced air droppable floating ice probes, which drill automatically a sensor stick through the ice and keep track and transmit ice & snow thickness, salinity, temperature, radiation balance. Then spray the ice sheet with thousands of them.
In the end cheaper than cryosat, and very lsmall error bars at least pointwise.
A few million Euros - one single cleanroom lab for semiconductor processing costs several times this amount.

Peter Ellis

I propose herewith to invent cheap mass produced air droppable floating ice probes, which drill automatically a sensor stick through the ice and keep track and transmit ice & snow thickness, salinity, temperature, radiation balance. Then spray the ice sheet with thousands of them.

Wow! What an amazing idea! I wonder why nobody's thought of it before! Please tell us as soon as you have a working prototype!

Peter Ellis

In fact, tell you what, why don't you tell us as soon as you have something that you can drop from 5 feet onto a frozen water butt, and have it drill through and measure the thickness.

Come on, time's a-wasting!

Chris Reynolds

Re Scientific Reticence and the IPCC.

Arctic.io was good enough to send me a paper about this. Boa5att linked to it above:

I strongly recommend everyone concerned about the IPCC's conservatism read that paper.


"I propose herewith to invent cheap mass produced air droppable floating ice probes, which drill automatically a sensor stick through the ice and keep track and transmit ice & snow thickness,"

Been done in the 1960s, google 'arctic sea ice penetrometer sandia'.

Chris Reynolds

Oops, that was the 1970s not 1960s.

Eli Rabett

""There is very high confidence that climate models realistically simulate the annual cycle of Arctic sea ice extent". Because I don't think there is, really."

Now some, (Crandles for example), but not Eli might think this a useful metric, given that the Mayans might be moving the Earth's orbit using time machine technology in preparation for a plunge into the sun.

The Bunny, OTOH, would be much more interested in how the freeze up and break up days in various places (Hudson's Bay, etc.) are changing.


9 in-laws here for the holiday week ... don't expect great things from me.

As Steve Bloom notes, the paleo is fascinating and not to be ignored, but it's hard to know exactly what to make of it. I came across the ultimate Arctic paleoecology time-saver yesterday, a very readable 2012 review of Ellesmere and Axel Heiberg fossils by Eberle with free full text.

Looking at the paleocontinent configurations, it's a real head-scratcher to see direct applicability to the climate of our rapidly approaching effectively ice-free Arctic Ocean. 'None of the above' might be the best description of near-term future climate.



It should be much easier than that. Likely all that is needed is a good surface contact (heat and freeze should do that) and the use of acoustic methods, sonic or ultrasonic. The electronics needed is simple; transducer, receiver, transmitter, processors, memory, battery, antenna.

On the previous thoughts. I agree with several of you that the real key now is the ice volume. It is crashing so very fast that even the deployment of sensors probably cannot happen fast enough to follow it.

I fully expect to see our first essentially ice free arctic summer day to week in September of 2015. There is a possibility that may happen in 2014. And it appears certain to happen by 2016 regardless.

I also fully expect to see our first ice free arctic winter day sometime in the mid 2020s. The ice volume plots suggest 2029. However, once the summer ice is gone and other feedbacks kick in (including ocean warming during the ice free summer), that will come sooner.

On current trends, we will see the first ice free arctic summer (90 days ice free) in 2016; 2017 at the latest. Then we see another month in the next year or two and another a year after that.

The IPCC models come no where near predicting anything like that. As has been noted, they are (badly; poorly) emulating the ice area trends.

Even then, there is no polynomial superposition of the various models that can be made to emulate reality. Reality is proceeding decades faster than any of the models or submodels.

They could try using some multi-model suite (e.g. Eileen Poeter's multimodel work at USGS) to try to find which model elements can best be combined to best emulate the reality. But, since none of the models is responding fast enough and the reality lies outside the bounds of the models, this won't work. It will be better than any of the assembled suites of models as they are currently portrayed. But it still won't work.

And once the ice is gone and other feedback loops kick in, all bets are off. The science is too far behind to gauge what happens next.

Almost certainly the jet streams will change in dramatic ways. As was noted previously, a new cold pole will almost certianly form over Greenland until that ice is gone. That too will radically disrupt the weather patterns we have all come to know and rely upon.

The great oceanic circulation will change too with highly unpredictable consequences. Those will first impact the northern hemisphere, but soon will reach the entire earth.

Then too there is the trend spotted by Dr. Hansen (and colleagues) for the spread of temperature variation to increase as the mean temperature rises. As this happens, the year to year variation of temperature, rain, drought and such will wreck havoc on agriculture. Within a few decades, agriculture as we have known it may well be impossible or at least impractical.

As all this proceeds, the tundra and permafrost are collapsing. These too are happening far faster than any model predicts and it is accelerating. We have entered a thermal runaway. The system has gone beyond its quasistable balance and is in the process of resetting to some new balance in conditions man has never expereinced. The ride from here to there is going to be bumpy.

We scientists do people no favors in not warning them about these dangers.


As someone who "Lurks & Learns" here frequently, and seldom has much to contribute, I would like to take this moment on the Eve of Christmas to give my special thanks to Neven and the myriad of contributors who make this site so special.

It is my hope that this holiday season finds each of you enjoying good health and special moments with friends and family.

As far as what "Mother Nature" has placed under the tree for us, I fear it will be many more "lumps of coal" than "promises of global cooling."

Eli Rabett

Sam, the damn things are going to get buried over the first winter and floated in the spring. Limited usefulness.


PIOMAS data shows only three years since 1998 when ice volume has increased, and in one of these (2000) it increased only very slightly. My question is, how can volume ever increase? Heat always moves from warmer to colder, so it must move, through whatever means, from the tropics to the arctic or, via radiation, to outer space. Since global warming, which we all know is very real, reduces radiation of the entire planet to less than the heat acquired through insolation, where can the extra heat go except to melting of ice? As long as the ice remains it can't heat water or the air over the arctic (which would be only small anyway) I suppose the only explanation is that in those few years when year over year arctic ice volume increases more Greenland ice melts. Is that the answer?


Eli, I remember writing my opinion on that claim as "so this isn't much of a claim" so I am glad to see you agree with me. :o)


I can heartily second Chris R's recommendation to "Climate change prediction: Erring on the side of least drama?" It is well-written, quite amusing and provides quite good coverage of climate science (though I could think of lots of other topics at IPCC, eg ag methane, where even the World Bank is trashing their (ie FAO's) understatement).

"The Boy Who Cried Wolf lost credibility, and so when the wolf finally came, the boy's cries were ignored, and he was eaten. Chicken Little, in contrast, was not ignored when she panicked over a falling acorn, but was joined by many others, who were then eaten by the fox who took advantage of their panic. Both stories provide cautionary tales about the importance of staying calm and reading situations correctly; but in the first case, because of lost credibility, a real hazard is discounted, whereas in the second, an imagined hazard leads to panic. "

"What does this mean for scientists? [Some authors] focus on the need to preserve credibility, suggesting that this is a guiding norm in scientific assessments. But mixing metaphors illuminates the problem that scientists face: of what value is credibility if it isn’t used to alert people to hazards that actually exist? What use is the preservation of scientific credibility if it comes at the cost of a persuasive alert? What is credibility being preserved for?"

Indeed, keeping your powder dry. For what? And for when? If three -quarters of the climate science community is striving to keep under the radar, then the remaining, responsible quarter takes on four times the flak. In other words, let someone else bell the cat.





When I'm less susceptible to seasonal cheer, I will read A-Team's last entry again but does it mean climate scientists have failed the test of courage.

I sympathise with them - I would probably fail this test too but give me a few years when death is nearer I hope I would do better.

But this may not be tested. I'm not in the firing line.

Seasons greetings.


It's not just climate science. For every E.O. Wilson speaking out on mass extinction and end of nature (happening w/o climate change), there are a hundred biology professors who wouldn't so much as give the Sierra Club a five dollar donation, even as the subjects of their publications vanish in front of their eyes.

From being in the belly of the beast so long, I see two distinct problems here. First, the modellers didn't understand Goldilocks (I have that painted right on my coffee mug).

In other words, sea ice alone is impossibly difficult to model non-empirically, never mind the general coupled climate model. You won't get anywhere, and they didn't.

The IPCC set itself up for failure by how they chose the terms of their remit -- joining itself at the hip to long-range, failed GCM. Was it a bad-decision-by-big-committee or did they simply lack the cajones? In the spirit of the season, I shall say the latter.


Otto Lehikoinen

on hudson bay, doing a chart depicting the regressed anomaly increase on (monthly)/probably weekly basis over the years (so 52 regressions and their interdependence(what's the word?) might make a pretty graph of how the melt is progressing. there is a clear change (eyeballing) in the anomaly pattern after 1998 autumn (before it the autumns were quite normal) but doing a linear reg one on weekly intervals might still give some means to guess the 1st winter without full ice cover. I don't now where to find the data on this: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/region.all.anom.region.13.jpg and anyway I'd probably mess up somewhere in the process. This sort of thing was done to some other climatic variable (regional CO2?) on monthly basis a year or two back, but if I've not seen it done to sea ice.

Otto Lehikoinen

And it appears I've not been looking: Gagnon & Gough (2005) http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/view/451


Neven, I want to thank you for showing the shortcomings of the IPCC report. Thank you as well, about your concern when Sandy hit. I agree our scientists are too conservative about global warming. It's not ice I'm concerned about, but people.

I've spent over a decade discussing issues with Denialistas and I've learn a few things in the process. When they brought up subjects about the past climate, and I didnit know about it, I studied it. The past climate or paleoclimatolgy is very different than our present world. There were major events, like North and South America connecting aroung 2.5 million years ago that changed thermohaline circulation. The Gulf Stream changed and the trans-equatoralial current changed. Before that was South America disconnecting from Antarctica and a circum-polar current created. Around that time was CO2 removed by the creation of the Himalayas. Those were major events and to compare the Earth as today to those times is apples to oranges.

Neven, what I care about is I've leave 6 children on this planet and many grandchildren. I don't want them having problems and I see problems in the future. Can we get the scientists on our side? Can we even have the grace to walk out of this Earth and know we tried?

Conrad Schmidt

Here is an analog to the American legal system. In a criminal case (individual vs the State) the standard of guilt is "beyond a reasonable doubt". In a civil case (think of a simple tort case) it is whichever side is more than 50%. In science discovery of something new, say the Higgs boson, cannot be claimed unless they are REALLY sure it exists. In ice science, however, where humanity's wellbeing is at stake, the standard should be more similar to a tort case. What are the probabilities? What is the potential harm? Who are the parties that will be affected? What are the costs of action or inaction?


Comrad, I hear what you are saying. The problem with individuals and state is individuals can't sue the state. How can we prove we are making drastic changes to our planet in decades that took hundreds of thousands of years in the past? I mentioned people that I'm concerned about, but there are also species we haven't even discovered. All are an asset and something to cherish.

I hear people saying the world has to cut back on energy or do that carbon credit thing. I want cheap energy for the people and support Thorium MSR research. I want a nuclear reactor that can't meltdown and doesn't support making nuclear weapons from it's products. Perhaps the world can cooperate and develop that 50 year old technology for the benefit of mankind.


Another analog to the legal system. Being a bad witness with inaccurate and shabby testimony is not a crime in it self. However to deliberately withhold or distort crucial information, is considered a crime. It works somewhat the same with science. Delivering a bad scientific report with inaccurate and bad predictions is not, and should not, be considered a crime, it is a different story with scientist who deliver reports that are purposely implanted with false statements.

I agree with Yvan, who states in the very beginning of this discussion, states that scientists are often under pressure to deliver reports that are somewhat political correct. However, being under presure is not an legitamate excuse for distorting science, just like being under pressure and risk loosing your job or your wife ect, ect, is not considered a legitamate excuse for purposely delivering a false testimony in a courtroom. Some of you like to refer to this report as ultraconservative, and it sure is. But when I am looking at theese fractions of this report, I also get a feeling that this is a report where key elements, such as various feedback loops, are purposely excluded from the calculations just to give a more political correct result. I think that criminally prosecuting the IPCC scientists is to go way too far, but I just want to remind all those that are defending the conservatism of this report, that there is really no excuse for distorting the truth, whether it is in a court of in a scientific report. Eventually I think the time will prove the predictions from this report wrong, but when it does I think it is more suitable to blame the politicians and the "big oil" for the havoc that will be following, not the scientists.


To all. May God bless you and I mean it from my heart.

Houstan, we have a problem that the world isn't solving.

Can we go forward with the grace that God will give us or fail in the process? I don't know. There is nothing wrong with love solving a problem and we have a big time problem. We've destroyed this world for centuries and it's our fault. I didn't want to do it, but I'm the blame and the people before me. I ask how can I fix it?

I know I don't want to leave this planet as a legacy (to my children....................) I'm far more responsible than that.


I don't know how to post a YouTube link on here, but............


dominik lenné

I drew a little bit of Flak because of the somewhat megalomanic proposition with the mass-produced thickness sensors. I was of course well aware that an outsider project of such size, which may or may not work out, has no real chance.
AFAICS the 70s-Sandia-penetrator project was a ballistic penetrator with deceleration sensors radioing its data up during or after impact - not a soft landing automatic station meant to remain stationary for months.
It may have a lot of problems hard to solve but surely not deceleration on impact, as Peter Ellis so sarcastically suggested.
Could be an interesting interdisciplinary development project of higher level science, engineering and manufacturing technology students...
So, and now I give You a break with this.

Al Rodger

I did tap in what became a rather long comment on this thread but it seems not to have survived. Maybe it fell victim to captcha or moderation or I was on the wrong thread. So I re-write it (& perhaps more understandably for the re-writing) & post in installments.

What actually is the alternative to these 'conservative' IPCC projections for an ice-free Arctic? Note that the IPCC want a 'physical basis' and natural variation accounted for. Is the literature providing such an alternative? I don't know of such.

If not, are there appropriate reasons for the IPCC's inclusion of those 'conservative' CMIP5-based projections? Does the quoted literature provide a solid-enough basis? I am inclined to say No.
Although each paper needs assessing individually, I will address here only Massonnet et al 2012, which should be a strong candidate being titled "Constraining projections of summer Arctic sea ice"

Al Rodger

On face value, the paper's conclusions appear convincing enough to fit the IPCC's citation requirement. Consider Fig 1. The NSIDC SSIE data doesn't look too out of place & adding 2012 would make little difference as these are 5 year means (to 4.6M sq km to 2012).
But while the average NSIDC trend also fits snug in Fig 2, Massonnet et al make zero discussion of the evident change in the NSIDC trend. The second half of the SSIE data (trend 190K sq km/decade) no longer fits snug!

What then lies behind the recent higher trend? Fig 3 displays SSIE having periods of higher trends in the CMIP5 models, occurring (to 1sd) for SSIE=2.2-4.4M sq km which is where NSIDC data is today.

Al Rodger

The CMIP5 models show decadal variations. If today's higher trend is due to such variation, I see no discussion of it anywhere. Discussion of decadal variation seems not to exist while the likes of Goosse et al 2009 and Holland et al 2008 appear to be discussing annual variation (like 2007 & potentially 2012). Note Goosse et al 2009 say such variability should peak at SSIE=3M sq km, ie in the next few years.

Without such discussions, Massonnet et al 2012 isn't robust enough for the IPCC's citation.

And we haven't even mentioned PIOMAS SSIV. Okay it is a model output but so is CMIP5.

We can extrapolate PIOMAS but what is missing is the physical basis for such projections. If we had them, then a good old rant at the IPCC would be arguable. Without it, we are just curve-fitting.

Al Rodger

If a linear regression of the most recent half of PIOMAS SSIV (1996-2012) is projected to zero, it gets there in 2019. But this projection has no physical basis. It is but curve-fitting.

But if PIOMAS SSIV is plotted against, say, UAH Arctic Ocean Lower Troposphere Temperatures, then there is a physical basis. The graph here plots SSIV against Annual (Oct-Sept) Ave Temps 1980-2012 & shows zero arriving when the temperature is 1.9 deg C above the 1986-2005 average. Without the means to seek that level of Arctic temperature increase within CMIP5 models, a simplistic alternative would be to take Arctic Amplification from IPCC AR5draft as x2.7. Thus zero ice equates to a 0.7 deg C rise in Global Temps above the 1986-2005 average which IPCC AR5draft table 12.2 sees as occurring 2016-35 (for all RCPs bar RPC8.5).
An alternative that ventures into 'curve-fitting' would be to fit a linear regression to the UAH temperatures being used. This yields a best-guess of 2022.

A similar exercise for NSIDC SSIE yields a UAH rise of 2.5 deg C, although the data doesn't look entirely linear. A regression 1996-2012 yields 1.9 deg C, the same as PIOMAS.

In the literature there is Mahlstein & Knutti 2012 (abstract only) who link SSIE to CMIP5 global temperature. Their figures show presumably NSIDC SSIE data averaged over years that fits their CMIP3&5 model predictions. It would be interesting to read the full paper & see how they reach their 2 deg C global temp rise for ice-free Arctic. Myself, I cannot reproduce their graphs showing observed SSIE v global temp. My version for data 1979-2007 gives 1.2 deg C to SSIE=1M sq km.

Artful Dodger

Hi Al,

We also have no physical explanation for gravity. Newton's Laws are just curve fitting. The real question is it a useful description of events?

When empirical observations disagree with theory, always go with the evidence.


Peter Ellis

Sorry Al, but that plot of PIOMAS vs troposphere temperature is just linear regression in disguise, since the temperature itself also has a trend.

You might just as well plot PIOMAS against my house price and discover that ice volume will hit zero when the house price hits £350k (or whatever).


Peter, Al,

So if the data are linearly de-trended and plotted, does the fit stay nearly as good? Even if it does, perhaps that fit is just a matter of fitting one accelerating trend dataset against another. So perhaps both datasets need to de-trend out the accelerating pattern. If that is done and a good fit still remains, how far towards saying there is a physical basis would that be?

Chris Reynolds


....except that there is no conceivable physical relationship between house price and Arctic sea ice. Really that argument is little but a case of reductio ad adsurdum.

Maths is just scribbling on paper without a physical basis. Your argument is valid, mathematically. But back in the real world physics hold sway.

Perhaps a stronger, physics based, objection is that a significant portion of the annual warming is from heat lost due to lack of sea ice in the autumn, and increased heating from the ocean in winter due to thinner ice. However that is also a factor acting against thickening of ice through the winter season. So perhaps it isn't so strong.

Al Rodger,

I have a copy of Mahlstein & Knutti 2012. If you want a copy email me, chris886222 at btinternet.com It's too complex to sum up, and I've not the time to read it properly. As I now expect a rapid transition it's dropped right to the bottom of my reading list. However as I have copy of that paper there is (was?) very likely a paywall free copy out there somewhere.


If the trend is removed then connection between global temperature and sea ice vanishes (more or less - IIRC) because interannual weather factors are the main driver of short term changes.

Chris Reynolds


To add - when I did it (using difference method to remove trend) I remember finding a downtick in temperature and uptick in ice after 1991 Pinatubo.

Chris Reynolds


Yes the Sandia work was a spin off from research into laying mines in the Arctic (explosive ordnance type mines).



Using global temperatures would mean you are losing a lot of the proximity of cause. Making the data more specific to what we are trying to investigate seems sensible.

Also, by looking for effects in later data perhaps we can hope to reduce any problem of confusing cause with effect. So don't use annual average, use previous couple of months

I would say that Jun to Aug temps north of 80N are pretty constant and have perhaps fallen a little while September volume is changing quite a bit so I would guess, before starting work to test it, that there would be little correlation. Does that mean we don't have a physical basis in temperature and should consider that an effect rather than a cause?

It would seem to me, reduced minimum volume is the cause of higher temperatures later in the year. Higher autumn and winter temperatures are involved in the process (to try and avoid saying cause or effect) that results in lower maximum volume which then causes a lower minimum volume.

Dismiss temperature as our physical cause?

Shouldn't we be looking for our physical basis in the albedo feedback? I.e. looking for big drop in extent early in the melt season tending to cause large volume drop later in the melt season.

In looking to try to show that relationship, it may be necessary to account for any effect of lower maximum ice volume tend to cause an effect on volume reductions later in the season.

Does measuring the size of these two components (and other factors) by multiple linear regression sound easily doable, and might it get us closer to saying we have a physical basis?

To extrapolate forward using these measures we would also need to extrapolate ice volume increases from minimum. Presumably we would want to base that on the minimum ice volume and perhaps also GHG levels?

Could this give us a physically based extrapolation? Would the error bars inevitably be too wide to be useful?

Artful Dodger

Here is the paper Chris refers to above:

Mahlstein, I. and R. Knutti (2012), September Arctic sea ice predicted to disappear near 2°C global warming above present, J. Geophys. Res.

"Key Points:

  • Our study is the first to use observational data
  • Based on model uncertainty and climate variability we present two uncertainties
  • We analyze the uncertainty of the observed polar amplification and sea ice"
  • Goggle Scholar finds 3 downloadable PDFs.
    (look for [PDF] on the right of each search result)

    The Authors also published this one page summary with charts from their presentation at the World Climate Research Programme conference held in Boulder, Colorado in Oct 2011.


groan. didn't 2012 already look like c)?

Al Rodger

Thank you, Chris R & Artful D.

I now have Mahlstein and Knutti, 2012 full text. While I have yet to entirely pin it down, I feel I am at the "Houston we have a problem" stage.

We talk of SeptSIE reaching 1M sq km by Year X and balk at the IPCC when they say this Year X will be decades away.
Mahlstein and Knutti, 2012 used to support this assertion have some very curious "observational" data showing in Fig 2.

M&K2012 use 10 year means for observations so any recent change in Ice trend will not feature. But they use the models to establish the Ice trend is linear with Global Surface Temps so that isn't so much of a problem.
Where I have a problem is this - Look at the last 17 dots on Fig 2. How can such 10-year averages for Arctic Ice sit in the range 5.8 - 5.0 M sq km for averages using 1980-2006 with 2007 just sub 5 M?

My take on it is that this data in M&K2012 is AugSeptOctSIA. They are plotting an Ice-free summer not September while using Area not Extent. Even using Area, you would expect this to involve larger temperature rises. Using annual AugSeptOctSIA v UAH(Arctic Ocean), it hits 1M at 3.1 deg C. Zero takes 3.9 deg C, twice the temp rise when plotting SSIE or SSIV. (Note this is data to 2011 only. R-sq = 0.57 which suggests linearity (I'm told), although not as impressive as SSIV v UAH with an R-sq = 0.74.)
Using SeptSIA v UAH, 1M sq km arrives at 2.2 deg C Arctic. With Arctic Amplification that is a rise of less than 1 deg C global.

Where this seems to be going for me is that the IPCC use M&K2012 as the one alternative method for calculating that the Year X is likely to be decades away. If M&K2012 are predicting something significantly different to SSIE = 1M sq km, or using significantly different observational data, that alternative evidential support showing "best estimate of 2°C above present" is looking at the wrong Year X. It thus becomes the exact opposite of 'support'.


Well, my first impression is that the Mahlstein-et all paper does a good job in framing the underperformance of most models. That’s the purpose.

Scientists are doing admirable work on modelling. Most projections are in themselves credible enough for regulatory efforts against AGW.

What they do well is start from representing known climate, but they get the timeframe progressively wrong when they enter future. In my own words, the balance, or buffering capacity underlying our biosphere, is more delicate than we assume. Researchers often use the term ‘sensitivity’ : it is probably larger, mostly through intricate feedback-loops.

For the ‘+1.5dC mean temp rise’-map (c); it depicts an area of app. 4.1 million km2.

We experienced +0.8dC since about the year 1900. I haven’t checked when the +1.5dC mark will be forecast in mean model range, but I guess it could be about 2040?

ASI extent is already 12% lower than map (c). What does that mean?

Is temporary recovery possible? Maybe, through what Mahlstein et all call ‘large interannual variability’. But that may not counter volume falling. MYI is nearly depleted, with it the last bit of hardy volume. Extent may linger at the end of winter. Because melt in ’11 and ’12 produced a large, fresh and relatively cold upper ocean layer.
But the essential MYI volume will soon be gone. That moment could well coincide with the first practical ice-free period in the Arctic Basin.

Is mean global temperature the right indicator? It may very well not represent cumulative energy stored within the biosphere. The bite is in all regionally active feedbacks.

Is +1,5dC the right benchmark? In several studies the ‘politically correct’ IPCC +2dC limit has been characterized as ‘not safe’. Also, 350ppm CO2 has been supposed as 'maybe safe'.
On the incredibly short timescale in which fossil energy is unleashed, the biosphere is subject to a singular evolutionary experiment.
It may well be that +0.85dC is the mark. To be reached in 2013?


Hi Al,
Saw your entry as I uploaded. I don't immediately get the calculations you present. have to read the Mahlstein paper first.
But I think you sense something in the same line as my thinking?

Artful Dodger

Hi Al (goedendag, Werther ;^)

From the Mahlstein paper:

"A certain level of warming, e.g., 1C above the reference period, corresponds to a best estimate of total September sea ice area based on the red line in Figure 2."

So perhaps compare predicted SIE in the paper to the NSIDC September mean SIE, thoughtfully summarized here by Larry? (click the image for a full view of the chart)

Next, do we notice how nonlinear the collapse of SIE is with rising temps? Some one care to run the numbers?



Morning Lodger,

I take it they see the reference period as '80-'07. they mention the observational points as '70-'07, based on 10-year running mean. Third, I think when they write 'area'
they interprete to what we refer to as 'extent', have to see if Al is right though.


The grey spaghetti represents the model outcomes. They are, what you call, 'nonlinear' yes, nice understatement. Or did you have another aspect of the graph in mind?

Whatever this paper may offer, it just illustrates how spot-on Neven's blog-thread 'Models-can they cope...' was.


New paper by James Hansen et al in review at Phil Trans Roy Soc:

Climate sensitivity, sea level, and atmospheric CO2

Cenozoic temperature, sea level and CO2 co-variations provide insights into climate sensitivity to external forcings and sea level sensitivity to climate change. Pleistocene climate oscillations imply a fast-feedback climate sensitivity 3 ± 1°C for 4 W/m2 CO2 forcing for the average of climate states between the Holocene and Last Glacial Maximum (LGM), the error estimate being large and partly subjective because of continuing uncertainty about LGM global surface climate. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify total Earth system sensitivity. Ice sheet response time is poorly defined, but we suggest that hysteresis and slow response in current ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state-dependence of climate sensitivity, finding a strong increase in sensitivity when global temperature reaches early Cenozoic and higher levels, as increased water vapor eliminates the tropopause. It follows that burning all fossil fuels would create a different planet, one on which humans would find it difficult to survive.


Al Rodger

I can claim with some confidence that Mahlstein & Knutti 2012 use Average Sea Ice Area for the 3 months August to October, not September SIA values. See graph here.
(The implications of this difference on its own is perhaps less than other considerations that I reckon together turn their projection of 2°C global temperature rise required for seasonally ice-free Arctic into 1°C. But I feel a bit more nmmber-crunching is required before explaining furhter.)

Chris Reynolds


I'd forgotten about this discussion over the new year. I'll consider what you say but right now am tied up between work commitments and some work on atmospheric blocking.

Artful Dodger,

Thanks for finding that paper, for some reason my search drew a blank.



I have tried doing a bit of what I was talking about over on the PIOMAS December thread:


Discussion there doesn't have to be limited to just SATire and me, others are welcome to join in the discussion. ;)

(No worries if you are busy though Chris.)


I was going to do a full rant then decided no. I do pose some questions and comments. Who is paying the piper? What are there biases? How much power and leverage do they have over the final results? In Canada it is getting terrifying what those answers are. Scientists are fired blacklisted, legally defamed and sued for giving the wrong conclusions. The agencies that are supposed protect the country and people from bad long term effects are neutered by watering down their powers and eliminating their budgets. All with policies that the Koch brothers would give a standing ovation to. The private media is more and more being taken over by big multinational conglomerates with the idea of using it as a mouth piece for there agendas and the public media is getting their budgets slashed and being cut off of their traditional information sources. I do think that this trend is happening in many other countries. So is it at all surprising that We are still seeing many papers still talking about post 2100. To me no. In fact I could see nothing changing until Manhattan Island is suddenly cutoff for a very lengthy time because a combination of storm damage and inability to repair the infrastructure because a permanent high water.

Chuck Banjomon

I'm not a scientist but from everything I've read and witnessed over the last ten years or so I can say.... expect the unexpected. I wouldn't presume that things won't get bad for a few more decades. I believe that when real change starts to happen it will happen very quickly. The collapse of the Greenland Ice Sheet will happen quickly. West Antarctica Ice Sheet, once it really starts to go will go relatively quickly and dramatically. Once this Climate Change really kicks in and the feedbacks get going I think we will see massive change within years, NOT decades. It will be dramatic and within your lifetime.

If I remember the Stroeve paper correctly, it said that the models that got the past trend right, had a much lower SIE to start with. I'll look it up. Found that interesting at the time.
This is to do with how the models are developed and tested.

The [coupled] climate models are [mostly] not tested by being run in transient mode, but in a steady-state mode. So they are run with constant "present-day" boundary forcings and compared with present-day average observations.

This means that they have a bias towards modelling sea-ice that is too stable, because the sea-ice has to survive for a 50-100 year test run with something like year 2000 CO2 levels.

So, why not test the models in transient mode?

A couple of reasons - firstly you want to use that test later on for attributing climate change to greenhouse gases, so you can't use a transient run for your testing. Secondly, errors in the ocean drift require a long (many hundreds of years, ideally as long as possible) spin-up of the model before the transient runs are started, and there isn't enough computing capacity to do that for every development test run.

It would be better [in sea-ice terms] to do development runs in pre-industrial conditions, but then you have the problem of not having good observations to compare your model with. Good observations only existing for recent decades (and even then they have problems).

A broader point about the IPCC - this was exactly the intention. If you go back to when the IPCC was established, it was because ad-hoc groups of scientists were saying more forceful things about the climate, and the powers-that-be wanted to tie the scientists into a process that would constrain them from speaking out.

The IPCC makes any scientists who warns of more extreme risks look like a mad alarmist, and also provides false reassurance to most climate scientists that there work is being listened to by working through the IPCC channel.


Surely the models are run until stable then you start the transient hindcast which means the run til stable has to be done with forcings for somewhere in the region of 1900 to 1960 depending how long your hindcast is going to be.

If there was no hindcast, then I could follow the point that with 2000 forcings low ice models might lose their sea ice and become unstable and get rejected for being unstable.

However with a hindcast, 1900-1960 doesn't look all that close to losing the arctic sea ice. So why would it be so unusual to get a model that is both stable and has a realistically low level of ice?

Models generally seem to regenerate ice in two years if it is artificially removed so the level of ice for the forcing does seem stable in the models but I am not sure how the long spin up is responsible for this unless they are being spun up with year 2000 forcings.


@crandles - There are two different situations.

1. For the IPCC experiments then the models are run with fixed 1860 conditions for a spin-up (ideally until they reach a steady equilibrium).

Then you have a transient run started from the end of that spin-up point with historical forcings up to nearly present-day, and various different scenario forcings up to 2100.

2. For testing purposes - ie when the sea-ice modelling scientists are testing changes to their parametrisations - then you can't do runs like that. It would take too long. So if you want to test a change in something like the cloud scheme, that might affect the solar radiation that reaches the sea-ice in summer, you have to do so with a shorter run.

Then you face a choice of doing this with fixed present-day conditions - where you have the best available observations of clouds, atmospheric circulation, etc - or with fixed conditions at 1860 - where most of the observations are missing.

--- It isn't a simple problem to fix, because there are constraints on supercomputer time and on the observations available. With the benefit of hindsight, though, it does seem pretty obvious that the models should have a stable Arctic sea-ice bias for this reason.

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