« Record dominoes 10: IMS sea ice extent | Main | Minimum open thread »


Feed You can follow this conversation by subscribing to the comment feed for this post.

Chris Reynolds

Let me stress at the outset. I found this pattern independent of the experts who are studying it. The first indication of this pattern in the literature is:
Hanna et al, 2012, "The influence of North Atlantic atmospheric and oceanic forcing effects on 1900–2010 Greenland summer climate and ice melt/runoff."

They find the abnormal Greenland blocking pattern while examining the infuence of various parameters on Greenland ice sheet melt. (Hat tip to Dr Jennifer Francis for letting me know about that paper).

Chris Reynolds

Forgot to add:

Chris goes on to explain what this means for UK summer weather and wonders if perhaps, possibly, maybe, this persistent blocking pattern could have something to do with disappearing Arctic sea ice.

Given the way I rounded off Summer Daze 2012, I take it that line was delivered with a wink. ;)


Alan Thorpe of the European Weather Centre talks about those patterns to the BBC




A great piece of research, I'd read the BBC story Friday, but your work adds more to the picture.

Lewis Cleverdon

Neven - its good to see your earlier remark of the need to extend the site's focus onto the consequences of sea-ice loss being put into effect. The implications of a new 'resident' high over Greenland for prognoses of rates of GIC outflow, and thus for SLR, appear pretty drastic.

Data since 2003 appear to show an average increase of km3 outflow of about 10%/yr, but that includes years prior to the inflexion point of 2007 that Chris identified. I should be very interested to read informed opinion of what that rate of increase would be by say 2017.

This interest is not about mere angst-raising, but rather about trying to get a measure on the period available for effective mitigation before the geopolitical stresses of SLR compound those of agricultural output decline. In short, what is the window for coherent global action.

Candid opinions on the 2017 rate of increase of outflow would thus be much appreciated.




I know the difference between weather and climate but.....


Artful Dodger

Hi Lewis,

Here is a good place to start. Then continue here.

Note that Dr. James Hansen says the critical unknown is the 'doubling time' of the Greenland ice sheet melt. Does the rate double every 10 years? Every 6?

He says GRACE results should answer this question soon enough.



Here are a couple of additional impacts.

If this is the summer pattern and with alot of heating in the Arctic, it would seem that as fall/winter set in, that the shift to cooler weather would trigger or enhance SLP's that were part of the shift toward winter.

In regard to anamolous lows, we had the August polar storm.

Then we had a low this week that moved over Alaska that triggered a 1 in 10 year wind event(now over the Canadian Arctic) that is producing strong wind and warmer air being pulled over the ice.

In the next week's forecast, we have two more very strong lows with potential to impact Arctic ice redevelopment. One is a 969 mb storm over the Canadian Arctic that pulls 14-16 C temps and strong winds over southern Greenland and another 978 mb low near Iceland. See the last frame of:


Finally, I am wondering about the impact on methane release. While we are just getting into the period of highest concentrations, the latest Barrow data show that last 2 points in August at approx 2080 PPBv, which is extremely anamolous.


Jim Williams

Three North Poles now. Axis, Magnetic, and Climatic. We can tell the children Santa lives in Greenland.

Protege Cuajimalpa

Chryosphere Today Sea Ice Area at 2.298*10^6 km2. Wow. I was not expecting a 20% drop on the record at the beginning of this melting season.

Espen Olsen


Depending on country he live different places and he is even called different names Julemanden (the Danish version) already live in Greenland, and Julenissen ( Norwegian version) live in Longyearbyen Svalbard. The Finnish: Joulupukki and live in 'Korvatunturi', and then there are a score more I guess.

Jim Williams

Then clearly the Danes were right all along Espen. Greenland is the center of the World (like in Dante's Inferno).


(OT, sorry, but ther's no Open Thread...)

I guess I don't need to tell you why everybody should sign Greenpeace's petition on


Please do !

R. Gates


Your noting those anomalously high methane readings at Barrow is important. The fact that there have now been two readings at those very high levels indicates a stronger signal. Worth watching and worth noting and I suspect the spike in methane levels will become an even more important topic as we head to an ice-free Arctic.

L. Hamilton

The Uni Bremen website has added new material explaining how their long time series (1972-present) is put together, and why in their data they won't compare this year's absolute ice cover with last year.

Artful Dodger

Hi Neven,

Is it too early to switch the Arctic Sea Ice Graphs page from SSMIS to AMSR-2 data?




Glaciers of course pay attention to climate not weather, and the signal on climate from them in Greenland is clear. Just one more example is Thrym Glacier.


Came across this.http://www.brantfordexpositor.ca/2012/09/07/a-worrisome-wet-wake-up-call-from-the-arctic
"This not only threatens our future and that of our children and grandchildren; it could also have tremendous negative economic impacts. Because climate change affects agriculture and food supply, energy systems, water availability, and weather conditions, it will be expensive. A study conducted for the Pew Environment Group concludes, "In 2010, the loss of Arctic snow, ice and permafrost is estimated to cost the world US$61 billion to $371 billion in lost climate cooling services. By 2050, the cumulative global cost is projected to range from US$2.4 trillion to $24.1 trillion; and by 2100, the cumulative cost could total between US$4.8 trillion and $91.3 trillion.""
This puts a very different spin on what will happen based on dollars not weather.
From my reading this is just from the cooling costs and does not include the costs of extreme slow moving weather systems that are projected. Also this report was done in '10 probably looking at melt out at the very earliest '50 and more likely 2100.


This looks like a slow motion replay of a head-on train wreck. At the current frame, the bits are flying off the locos, and the carriages are still intact. However, we all know that they have a lot of momentum, and that the passwengers are about to pay the price of the recklessness of those who ran the railroad. All the directors are, of curse, cashing their bonus checks for their cist-cutting successes.

"Quos Deus vult pedere, primus dementat!"

Protege Cuajimalpa

A4R and R. Gates:
I enter to Methane at Barrows Alaska and I look for the values at the last year. There I see three readings, not only two. I agree that this comment is very important, not only for the countries close to the Arctic but for humanity in general. Good information!

Jim Williams

Methane probably deserves a thread of its own. If we get a third reading up that high it will probably deserve headlines. It might even become the October Surprise.


fredt34 -

> I guess I don't need to tell you why everybody should sign
> Greenpeace's petition on

> http://www.savethearctic.org/

> Please do !

Sorry Fred. It is too late. The dawn has broken on a new age. There is nothing we can do now to stop it. The arctic will thaw. In human timescales it is irreversible. We went too far. We pushed too hard.

We have entered a hyper thermal akin to and probably greater than the paleocene-eocene thermal maximum. Hold on to your shorts and get ready for a wild ride.

The discussion now centers on understanding what is happening in the arctic, how fast the change is happening, and what the collateral effects and impacts are on climate and weather.

In this thread Neven notes the change in weather dynamics associated with the loss of arctic ice. He posits (I believe) that the mass of ice on Greenland is now forming a new center for high pressure with a ring of low pressure zones around it. This leads to cool rainy summers in that band (including England and much of scandinavia.

The high we saw in 2007 was truly stunning. This year is very impressive. In both cases, this set up the system of lows around it and as another commenter noted, it essentially forms a new pole; a weather pole.

This is not something anyone that I am aware of thought about enough to anticipate. In retrospect it is fairly obvious. And that is one of the problems with the climate models. They omit all sorts of positive feedbacks, some negative feedbacks and things like this.

One of my concerns has been what happens to agriculture once the arctic ice is gone. As the temperature difference from equator to pole flattens, the driving force for the major air circulatory cells breaks down. That should lead to sloppy flows in the circumpolar jet stream and the continental jet stream. That sloppiness should lead to great variation in weather across the northern hemisphere. That variation is what may make agriculture in the northern hemisphere near impossible. Year to year prediction of the weather to know when to plant and what to plant may be more than a problem, it may not be solvable.

However, if as is being suggested, Greenland acts as a new weather pole anchoring the jet streams, weather may change dramatically, but it may for a time be somewhat stable.

Once the Greenland ice fails, that anchor will be lost. But it perhaps gives us some limited time to respond (decades at most).

The climate modelers have yet to let go of 2030, 2050, or 2100 as timeframes of concern. What they have as yet failed to embrace is that the models by lacking the feedbacks have failed miserably to warn us about the danger. Instead of losing all arctic ice sometime next century, we now must expect to see the first ice free arctic summer day in just a few years; most likely 2015. And to see the LAST ice free arctic winter day sometime in the 2020s, most certainly by 2029 but probably about mid decade.

The modelers suggested based on their models that to be safe we had to limit atmospheric CO2 to 450 ppm. That changed to 350 ppm (we are at 400). Even that looks dubious now. The time for action to avoid cataclysmic change was decades ago. We didn't know. We didn't see. And even now, many of us do not want to even look.

So, the arctic is lost. As a biome it will now see massive change. Future archeologists will note it in the geologic record as the marker for a new age. We aren't stopping there.

To successfully do anything meaningful would require us to decarbonize at a rate of over 10% a year for decades. That is simply not possible without massive starvation and die-off. Not doing so only means that the the Earth as a system will force the issue with the same result only more severe.


That is at least the third time I have seen high readings like that. i.e. it happens regularly and is highly likely to be a small leak in the equipment.

Normal - nothing to worry about - move along ...

Janne Tuukkanen

So, will CT area go below 2? Probably not, but a few years ago most of us thought this wouldn't be a relevant question in our life times.


The High pressure presented by Chris over Greenland is in part natural as a consequence of having 2 miles of ice instead of air. This said, there has been strange appearances of persistent larger highs over Greenland. These anticyclones have a huge impact on weather quite a distance around Greenland.

The real culprit is what I call the Cold Temperature North Pole, literally formed by the collusion of ice and air, it varies in location daily. a whole lot less recently especially during summer. I explain a little more on my blog: http://eh2r.blogspot.ca/

Usually the coldest air is at a High pressure location.

Jim Williams

yes crandles

Janne Tuukkanen

And in the lighter side, as I've been reading various articles about science communication. How to deliver a message:


Jim Williams

Foo! the blankety system ate by giggle tag surrounding that: "less than"giggle"greater than"yes crandles"slash less than"giggle"greater than"

Chris Reynolds

****A New Weather Pole****

Sorry but this is not a correct interpretation.

Give these links a short while to work, they're to NCEP/NCAR not links to images.

Here is the mean 500mb geopotential height.

Here is the anomaly from the long term mean of geopotential height.

What is going on is that there is a new regular ridge in the thickness up towards Greenland. This corresponds with a ridge in the pressure field. It shows up in the anomaly (difference from long term mean) as a peak, around which there is a ring of troughs (or lower anomaly). These are real features and are experienced on the ground as a high pressure system surrounded by lows. This is seen best in the graphic from my post that Neven reproduces above.

However: It can be seen from the plot of mean geopotential height that the center of action remains around the geographical pole. With Greenland clearly being offset to the side on the downward slope of geopotential height towards the Arctic itself. Therefore the idea that the centre of action has somehow shifted to Greenland is mistaken.


I very nearly commented to that effect, but it's been noted so often, I really couldn't be bothered.

Jim Williams

Chris, what is going to happen to those geopotentials once the pole is normally ice free in Summer? Isn't the effect of being the center of darkness cold going to be strongly attenuated?

That's not going to happen to Greenland for quite a bit of melt. (Not willing to put that in terms of time.)

Chris Reynolds


Greenland mass balance and ice sheet run off are a major issue here.

The strength of the high pressure anomaly over Greenland is measured in Hanna et al by Greenland Blocking Index (GBI). They find statistically 'highly significant' positive correlations between GBI and run off, with other indices examined being less significant.

So this pattern has now been a regular feature for 5/6 years, with the pattern not occurring regularly enough to survive the differencing technique I outline for the period since the 1950s. Furthermore this pattern starts with the crash of 2007.

Rather than mass balance, surface melt is perhaps a better thing to look at for the impacts of this anomalous high pressure on the ice. This is because insolation driven melt due to clear skies under high pressure will be faster to respond than mass balance - which is the result of longer term forcings on the ice sheet. Surface melt this year has been exceptional.
But there is little evidence of a post 2007 inflection.

Despite this, the implications of Hanna et al (coreelations) and the persistence of this pattern suggest it could be a key player in the increasing melt, both in area and ultimately mass balance, that will come from Greenland as the Arctic's transition to a seasonally sea ice free state continues.

What this does mean is that we have feedbacks within feedbacks within the Arctic. So for the Greenland ice sheet the prospect is uncertain, but more increases of area and volume melt are certain.


This is my first post after years of reading the information on this site. First of all thank you to Neven and the regulars who post on here. I read all the discussions with interest.

I am a qualified Scientist but I am interested in the term insolation that is often used here. What to people mean by insolation in terms of ice melt?

Also, I find the shift in weather patterns fascinating. Meteorology is my first love and I'm keen to know what the fellow followers believe the effect on weather patterns will be this coming winter, particularly over Europe. Will the Greenland High still play a big part into the winter, or will the re-freeze subdue its effect?

Steve C

Chris Reynolds wrote:
"Rather than mass balance, surface melt is perhaps a better thing to look at for the impacts of this anomalous high pressure on the ice."
And he also wrote:
"What this does mean is that we have feedbacks within feedbacks within the Arctic."

Absolutely, and to specify a couple of feedbacks that might not (yet) be obvious to some of us neophytes:

1. Persistent high over Greenland does certainly imply sunny summer skies there. We've seen evidence of a dramatic fall in Greenland ice sheet albedo, and there's every appearance that as ice melts there, more and more dark material accumulates on the surface, lowering albedo further and increasing pace of melt (until the stuff gets thick enough to actually insulate).

2. Persistent highs over Greenland mean persistent clockwise winds around the landmass. This will tend to accelerate transport of the thickest ice in the arctic off the northern coast, and south across the Fram strait, where prompt melting is inevitable. This contributes mightily to net loss of ice volume. A slight mitigation here is perhaps less transport out the Nares strait, but that narrow channel isn't as important as the wide, deep Fram.

Drift buoy maps here show the fairly rapid movement of the buoys from the N. of Greenland to the Fram. Some of the ice thickness maps already show ice being thicker above Elesmere Island than above Greenland, reflecting this net ice export near Greenland.




Post the methane website link.




R. Gates

Related to methane, Barrow has now had 3 flask measurements at the highest levels ever recorded. Could be error or leaks, or could be something else. With the record low sea ice and other studies showing methane bubbling up in greater amounts than expected in many areas around the Arctic, both from the floor of the ocean and from the land/permafrost, these three anomalous readings from Barrow in the past few weeks deserve close attention. Here's a graph:


Chris Reynolds
Related to methane, Barrow has now had 3 flask measurements at the highest levels ever recorded.

Yep, erroneous measurements.

Could be error or leaks, or could be something else.

[bangs head on desk]

What else, go on, please expand.

R. Gates

Don't bang your head on the desk...puleeeze!

Anyway, here's a graph to show these latest measurements in perspective over the past 12 years:


We certainly know methane levels will be spiking higher and higher over the next few years, and this is exactly the time of year we'd expect to see such spikes and exactly the kind of melt season we'd expect to see such spikes.

In general, the rapidity of the sea ice melt has taken nearly everyone by surprise, and a close cousin of that surprise will be the rapidity with which methane levels will respond.

Of of course, these could all be anomalous readings. We'll know in a few weeks.

R. Gates

In last post, last sentence should have read:

"These could be all simply erroneous readings..."

For certainly they are anomalous since if they stand they'd be the highest well mixed atmospheric methane levels ever recorded at Barrow (or perhaps anywhere) using this flask technique?

Chris Reynolds

R Gates,

I've followed that data for years, not like sea ice, but I keep my eye on it.

Those readings mean nothing in the context of climate change. And, on different reasoning, if you're waiting for some massive blow out of methane it isn't going to happen that fast within the next few decades.

What's the most likely option? Given that high values in preliminary data (orange points are prelim) are not uncommon:

1) That it's erroneous readings.
2) That it's the start of a massive blow out.

Occam's razor suggests 1...

Especially as the other sites in the region (Alert, Svalbard, Finland, Greenland Summit, Poker Flat; Alaska) do not show matching spikes. And yes, I did have to spend my time checking those out.

R. Gates


I agree that the most likely explanation is erroneous readings, and in no way was suggesting some big methane "burp" had occurred. However, please keep in mind that Barrow is the only Arctic location to record daily average methane readings as those other sites I believe are all monthly averages. Thus, those other Arctic sites would not be comparable to the readings from Barrow.

Mauna Loa is the other site that also records daily averages, but of course methane levels are traditionally much higher over Barrow than Mauna Loa. See:


So we'll agree for now that these readings are likely "erroneous", but I don't expect a nice gentle rise in methane levels over the next years and decades, but some rather dramatic "mini-burps", taking us over 2000 and then over 3000 ppb. This rise in methane will be just as dramatic as the sea ice decline has been as they are closely related of course.



I haven't looked at the flask readings for methane for some time. I remember not being able to find why certain readings were rejected. Are they rejected because the measurement process had some flaw or because they were outliers - or both?

The AIRS maps of methane concentrations show methane concentrations swirling around so is it possible that rogue readings are localised effects?

Are the green crosses rejected points?

I've just looked at the August AIRS maps for 2003 to 2012. The 2008-2012 maps seem to have quite a bit more methane showing than 2003-2007.

Two or three years ago I read that concentrations of methane near the emitting sources can be hundreds of times greater than background levels. This suggests there may be local effects.

Has anyone done any work to compare the spatial distribution of methane concentrations with weather patterns?


On methane...
I've archived Barrow graphs with prelim outliers for fall '11, also up to 2200 ppb.

I think the NOAA branch needs a year before measurements are thoroughly checked and summarized into the 'definite' graph. Most likely these are erroneous samples.


Remember that Barrow stopped in situ sampling this June (due to budgetary concerns). The almost continuous measurements were much more likely to pick up whiffs of methane than the flask measurements now taken.



Jim Williams
"It might even become the October Surprise."

I have only been visiting this site for several months and am fairly certain that I do not understand most of what is discussed, however my experience in manufacturing is that "fresh eyes" often can be a source of creativity.

Having said this, could the October surprise be a dramatically slower refreeze as successive lows across open water disrupt what we have all come to expect from past experience?

Steve Bloom

Lodger: "He says GRACE results should answer this question soon enough."

Remember that what they won't answer very soon is the question of whether ice streams can undergo rapid collapse. Of course if the answer is affirmative, we'll have other methods of observing the effect.

R. Gates

I've been in contact directly with the personnel at Barrow. Hope to have some additional information related to these readings and the process to scrub them from the data or confirm them. They certainly are outliers.

BTW, the question was asked was the green plus marks mean. This from the ESRL site:

"+ Symbols are thought to be not indicative of background conditions, and represent poorly mixed air masses influenced by local or regional anthropogenic sources or strong local biospheric sources or sinks."

Ghoti Of Lod

GRACE results though amazing and informative seem to take 5 or more years to be published. We are going to miss much of the Greenland melt action if we have to wait for GRACE results. This is a huge pity because the mass loss GRACE showed in the previous publication (especially Antarctic) was huge and delaying showing that Greenland is melting away doesn't help.


R. Gates


I've just had a bit of a shock. I Googled that quote you gave and one of the results I got was an answer from me to the same question. I'd forgotten I'd found it. Time for a holiday perhaps.

About the image you point to: if the high provisional readings become green crosses and are local whiffs of methane then these wiffs seem to be on an upward trend. OK, that will drive staticians mad but eyeballing says "maybe yes".

Another question I do actually remember asking is:"Does methane emitted in Arctic regions have any local heating effect before it becomes well-mixed?"

I continued

1. Weather over Siberia can have blocking patterns with little wind.

2. Tamino’s blog, if I remember correctly, mentioned that rises in methane levels can vary by several weeks at different measuring stations.

3. Concentrations of methane near the emitting sources can be hundreds of times greater than background levels. Clearly, if these concentrations reached any height there would be a local warming effect. If these concentrations reached one hundred metres above the emitting sources these concentrations would occupy about one percent of the atmosphere above the source. One hundred times a background level would double the warming effect of methane in the locality.

Warming areas where methane is emitted with methane that is not well-mixed is clearly some sort of feedback. Is it vanishingly small? I would be interested to know if anyone has done the work to dismiss it definitively.

No answers then. Any now?

R. Gates


5 samples now from Barrow have been over 2000 ppb over the period of a couple weeks. It will be at least 18 months or so before this data is either officially confirmed or scrubbed from the database or marked with the "green plus" sign.

I am still waiting to here more about this process from several sources directly involved, but here's a few thoughts:

1) I think most of us realize that eventually methane levels are going to be going much higher if present overall Arctic warming trends continue. These kinds of big jumps in methane levels in one season, while not seen before, are not impossible, and would be the "other side of the coin" to the dramatic declines in sea ice we've seen. They both reflect rapid changes in the Arctic.

2) It is curious to me that none of the anomalous green plus signs are negative anomalies. If these were true random anomalies, you'd think they'd average the same number higher or lower than the long term trend. So the anomalies, at least at Barrow, are all on the plus side of things. Curious.

Steve C

As long as we're on methane...can anyone explain why methane releases and levels reach their peak around early January, and are at their lowest in July and August?

In terms of warming clathrates and thawing permafrost, the annual pattern should be exactly the reverse.

I'm thinking that perhaps microbes oxidize the methane before reaching the atmosphere, but that these microbes can't metabolize at the lower temps of winter.

R. Gates

Some recent comments and research on methane that some may be unaware of:


And this rather lengthy posting by Professor Peter Wadhams of Cambridge:

"In a January 4th post on "Real Climate", David Archer addressed those who are raising concerns about the speed of ice loss in the Arctic and the resultant potential for warming water temperatures to thaw frozen methane and release it as gas to the atmosphere. In essence, he dismissed such concern as a form of unfounded alarmism making "much ado about nothing". In this rebuttal, I would like to respectfully challenge this dismissive stance and assert that severe dangers are arising in the Arctic which call for the full attention of humanity.

The present thinning and retreat of Arctic sea ice is one of the most serious geophysical consequences of global warming and is causing a major change to the face of our planet. A challenging characteristic of the behaviour is that both the rate of retreat (especially in summer) and the rate of thinning in all seasons have greatly exceeded the predictions of climatic models. The sea ice cover of the Arctic Ocean, particularly in summer, has been in retreat since the 1950s at a rate of about 4% per decade which has recently increased to 10% per decade. More seriously, the thickness of the ice has diminished.

Satellites can track ice area, but ice thickness distribution is most accurately measured by sonar from underneath the ice. Since 1971, I have been going to the Arctic in UK nuclear submarines, mapping the ice thickness using upward-looking sonar along the vessel's track. U.S. submarines have also allowed such availability. Opening these submarines to scientific work has been a marvellous service to climate research. It was thanks to submarines that I was able to show for the first time that the ice in the Arctic is thinning (in a 1990 paper in Nature [2], showing a 15% thickness loss in 11 years), and recent work from UK and US submarines now shows a loss of more than 43% in thickness between the 1970s and 2000s, averaged over the ocean as a whole [3]. This is an enormous loss - nearly half of the ice thickness - and has changed the whole appearance of the ice cover. Most of the ice is now first-year rather than the formidable multi-year ice which used to prevail.

The thinning is caused by a mixture of reduced growth in winter (because of warmer temperatures and more heat in the underlying water column) and greater melt in summer. A change in the direction and speed of ice motion has also played a role, with the ice departing quicker from the Arctic Basin through Fram Strait rather than circulating many times inside the Arctic.

The summer (September) area of sea ice reached a record low in 2007, almost matched in 2011, but what is most serious is that the thinning continues. It is inevitable that very soon there will be a downward collapse of the summer area because the ice will just melt away. Already in 2007, measurements indicated that during the summer there were 2 metres of melt off the bottom of ice floes in the Beaufort Sea, while the neighbouring first-year floes had only reached 1.8 metres during winter - so all first-year ice was disappearing. This effect will become more important and will spread throughout the Arctic Basin.

There is currently disagreement about when the summer Arctic will become completely ice-free. It depends on which model is being employed. My own view is based on purely empirical grounds, that is, matching the observations of area from satellites with observations from submarines (combined with some modelling) of thickness to give us ice volume. If we think in volume terms instead of area terms, the downward trend is more than linear, in fact it is exponential, and if extrapolated it gives us an ice-free summer Arctic as early as 2015 or 2016.

Others have talked of later dates, like 2030-2040, but I do not see how the trend of summer ice volume can possibly permit this. Those who agree include W Maslowski, a leading ice modeller (Naval Postgraduate School, Monterey), and the PIOMAS project at University of Washington which generated the data shown below [4].

The figure shows the minimum volume of Arctic sea ice in midsummer, based on areas observed from satellites and thickness trends inferred from submarine observations. Extrapolation leads to a zero volume in 2015. It must be pointed out that this perspective stands in direct contradiction to very complacent statements about the Arctic sea ice from the IPCC in the AR4 report of April 2007 saying the sea ice was very likely to last beyond the end of the century.

The ice retreat is having major impact on the planet. The Arctic is the most rapidly warming region on earth (warming at 3-4 times the rate of low latitudes). It has become widely accepted that Arctic amplification of global warming is due to the albedo effect of sea ice retreat. The increased open water reduces the albedo (fraction of solar radiation reflected into space) and causes warming at high northern latitudes to be much faster than the tropics, with enormous implications for climatic instability. Secondly, the summer retreat of the ice from the wide Arctic continental shelves (particularly the East Siberian Sea) allows the shallow surface layer to warm up, bringing temperatures of up to 5 degrees C right down to the seabed.

Quantification of this effect has only very recently been attempted, in a paper to the 2011 AGU by Hudson [5]. The startling conclusion is that the rate of warming of the Arctic from the sea ice albedo effect could double or worse, once the Arctic Ocean is ice-free in September. And it could double again, once the ocean is ice-free for half the year. But the timescale makes this all the more worrying.

The scientific community has drawn attention to the risk of dangerous climate change if the world does not reduce greenhouse gas emissions - a worthy and critical objective. However, I wish to point toward a much more immediate problem that does not seem to be recognised among the climate change community at large: This is the problem of rapid retreat of Arctic sea ice, and likely consequence of catastrophic methane feedback.

These rapidly warming temperatures are accelerating the melt of offshore permafrost, releasing methane, trapped either as methane hydrates or as free gas beneath the permafrost, and causing large plumes of methane to appear all over the summer Arctic shelves (observed for the last 2-3 summers by Semiletov and colleagues on joint University of Alaska - Far Eastern Research Institute cruises). Methane levels in the Arctic atmosphere have started to rise (measured by Dr Leonid Yurganov, Johns Hopkins University) after being stable for some years. As methane is a very powerful, if short lived, greenhouse gas (as much as 105 times as powerful per as unit weight of CO2 over a 10 year time horizon, though only lasting about 8 to 12 years in the atmosphere), this will give a strong upward kick to global warming.

According to research crew leader Igor Semiletov, "We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale - I think on a scale not seen before.... This is the first time we've found continuous, powerful and impressive seeping structures more than 1,000 meters in diameter." [6] He has also described how warmer temperatures are making their way down to the bottom of the shallow sea in the Arctic continental shelf areas: "When ice has gone, there are stronger winds and waves and a deeper mixing of water which causes the comparatively warm upper layer to mix with water at deeper levels. There are already studies which confirm that in some areas, bottom temperature in summer is 2 to 3 degrees above zero Celsius (freezing). As this warming spreads to a larger area, the more that shelf-based permafrost will thaw." [7] There have been warnings that a major methane outbreak may be imminent.

In a piece Archer co-authored in 2009 [8], he acknowledged both the significant warming power of methane and the fragile and "intrinsically vulnerable" nature of hydrates: "There are concerns that climate change could trigger significant methane releases from hydrates and thus could lead to strong positive carbon-climate feedbacks. .... Methane hydrate seems intrinsically vulnerable on Earth; nowhere at the Earth's surface is it stable to melting and release of the methane." In this same piece, Archer affirms another key factor: "Rapid warming well above the global average makes the Arctic hydrates particularly vulnerable to climate change."

Archer clearly acknowledges the vulnerability of methane hydrates to thawing in response to rising Arctic temperatures. Accelerating ice loss can only accelerate that temperature rise through the albedo effect, so we should be regarding the potential loss as an imminent and urgent crisis. Ira Leifer, from the Marine Science Institute at UCSB, describes the mechanics of a "runaway" methane feedback: "A runaway feedback effect would be where methane comes out of the ocean into the atmosphere leading to warming, leading to warmer oceans and more methane coming out, causing an accelerated rate of warming in what one could describe as a runaway train." [9]

Given that this "train" would be one way and feed upon itself in a way that might well be unstoppable by humanity, it would seem to be a classic case where the precautionary principle should be invoked as a justification for action."


With the Met Office still officially saying 2030 for an ice free Arctic, Dr. Wadhams is quite specific in thinking 2015 or 2016. Now, who seems more likely to be correct? And if Dr. Wadhams is more correct on that score, who are you going to believe-- those who say methane is not an immediate threat, or Dr. Wadhams who thinks it is very much so.

Just food for thought.

Chris Reynolds


I don't know how much local reduction of outgoing longwave occurs. However over leads and flaws in the ice local convection due to latent and sensible heat inpouts from open water cause convection plumes of around 1km in height, enough to potentially punch through the winter inversion, which is weakening anyway. This would probably overcome any localised heating effect of methane reducing longwave emission - by increasing downwelling to surface. It would also mix the methane. Leads and flaws are the main way methane gets out from under the ice.

This vertical mixing might explain why I've been able to detect a pattern of enhanced methane concentration over Laptev, where Shakhova and Semenov have found plumes in the ocean.
Now Dr Yurganov has detected these emissions using a different system.

Over land the prospect for such vertical mixing is reduced. so perhaps there might be a low level warming effect under methane pockets. I had thought that a model like modtran might help.
But it does the whole column, I'm not aware of a model that could address the situation in the lowest 1km with low lying raised methane levels.
NCAR seems to do the same thing as modtran.
Source page for those.

I'm not aware of any research into the issue of warming due to low lying methane pockets. Perhaps Dr David Archer could help you.
You might also try Dr Katey Walter.
She's done a lot of work on lake emissions on permafrost. Maybe the effect you describe is something she's considered.

About atmospheric mixing and weather.

This paper uses a 3d chemistry transport model.
Chen, Y., and R. G. Prinn (2006), Estimation of atmospheric methane
emissions between 1996 and 2001 using a three-dimensional global chemical
transport model,

That's a model driven by NCEP/NCAR weather, like PIOMAS, so is the kind of study looking at mixing processes with weather.

Fisher et al, 2011, Arctic methane sources: Isotopic evidence for atmospheric inputs. They look at C13 ratio in methane, in part of the study they note:

Footprint emission sensitivities for air arriving at Zeppelin and at the ship were calculated using the Lagrangian particle dispersion model, FLEXPART [Stohl et al., 1998]. The highest CH4 mixing ratios were measured in air masses from Siberia. The atmospheric transport on a twenty‐day timescale shows that the Zeppelin observatory is highly sensitive to surface emissions in the Arctic and particularly to emissions in high latitude Eurasia in winter [Hirdman et al., 2010]. Emissions that led to the highest observed CH4 mixing ratios in the summer 2008 study period (04–08 September) were from northern Siberia, crossing a large area from the Ob River to Eastern Siberia, including the East Siberian Arctic Shelf. The mean source signature, d13CCH4, for these specific days was −65 ± 3‰. Assuming only wetland (−69‰) and gas leaks (−51‰) are responsible for this CH4, then this signature may be apportioned to 78% wetlands and 22% gas leak, but there may also be significant input from East Siberian Arctic Shelf emissions [Shakhova
et al., 2010b] with variable d13C.


So although, obviously, wind mixing does shift methane about, determining sources isn't trivial.

Chris Reynolds

Steve C,

The observation you describe is due to the very low levels of hydroxyl (OH) radicals in the atmoshere during winter, but higher levels in summer. OH radicals are produced by dissociation of H2O2 under UV light. They react with methane to break the methane down.

Chris Reynolds

R Gates,

Whilst I've now aggressively revised my expectation of a seasonally sea ice free Arctic to this decade, and possibly within a few years. The reasoning I outlined in my posts on methane stands.
However the Siberian Shelf clathrates should be watched.

What the earlier prospect for a seasonally sea ice free state does mean is far greater concern over Arctic permafrost.
Lawrence, 2008, Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss.

None of which constitutes a doomsday scenario.

Methane is very probably a chronic, not catastrophic issue. I've yet to see strong evidence that we're on the verge of a methane driven catastrophe. From my reading the evidence strongly shows it's a serious additional problem.

R. Gates


I agree with the "serious problem" versus "methane driven catastrophe" perspective, but to put it into perspective, I personally like to think in terms of what even some modest increase in methane output from the Arctic region (from sea floor or land) might mean in terms of temperatures by 2100. Suppose we take 3C of warming for the doubling of CO2 as a starting point. What additional warming might be get from some modest acceleration in the growth of methane concentrations? 0.5C? 1C?

Now, there are certainly those who are taking a very urgent approach to this methane issue (for example at http://a-m-e-g.blogspot.com/)

Their's is certainly a worse-case scenario. But on the other end of the extreme, we have people who are of course not concerned about anything related to anthropogenic effects on climate.

If the truth is somewhere in the middle- then the "serious problem" level of concern is just about right. Hard to take much comfort in that.

Climate Changes


Methane is created near the Earth's surface, primarily by microorganisms by the process of methanogenesis. It is carried into the stratosphere by rising air in the tropics. The recent decrease in the Northern's Hemisphere Ice cover is letting trapped CH4 out directly under the Arctic atmosphere. Tropospheric height declines towards the pole thus shortcutting the distance CH4 needs to travel to reach the Stratosphere. Uncontrolled build-up of methane in the atmosphere is naturally checked by methane's reaction with hydroxyl radicals formed from singlet oxygen atoms and with water vapor. Sunlight at the tropics naturally keeps a balance but the Arctic night allows the build up of Methane over the NH winter until the Sun returns in Spring when is primarily removed by conversion to carbon dioxide and water.

Recently Nasa confirmed that the nuclei needed to form Noctilucent Cloudshttp://spaceweather.com/gallery/index.php?title=nocti&title2=NLC (NLC) possibly comes from space (http://science.nasa.gov/science-news/science-at-nasa/2012/07aug_meteorsmoke/) but where the H2O comes from is still a bit of a mistery since NLC's form at about 80km high.

NLC's form over the months of May through to August and Methane readings are also at their lows over those months (though sightings in September are becoming more common). The resulting H2O left by the CH4 could be the main net source of the ice that make up the clouds. That being the case, it would make NLCs's beautiful but also a Harbinger of bad news.


Chris and R Gates, Methane hydrates may be a looming problem, but it is still a very abstract not solidly quantified issue, it is largely the same as climate change in general, scientists like Wadhams , solidly right about everything they wrote, are thinking way ahead of the time when foreseen reality sets in. It is the main reason that politicians do nothing about the problem, its not tangible enough until it hits a sizeable portion of a population. Like most doctors act swiftly only when illness shows, even though prevention is the fountain of youth.

I am an advocate of adaptation, the only thing we can do is when we have no choice but to do it. So we are like Caribou waiting to cross one island to another with better aroma of fresher smelling forage. We wait for ice to come back, yet the crunching noise of the pack is never heard. Somehow we adapt and accept a lesser quality of life.

I find some strong similarities between NW Europeans and Arctic dwellers, where climate change hits most evidently. Soon the plight of the Arctic will be shared by all. And then again, all will adapt. Its better to know what is coming then just waiting for it to happen. Announcing the looming change is the least we can do.

2013-2015 with no sea ice is a small possibility, but not before the North Pole is accessible from the Thames in a few days with a common sea worthy boat. So its more like after 2015 , but that is irrelevant, when the cold temperature North Pole stops moving during summer we know sea ice has lost its grip over climate.

Chris Reynolds


"It is the main reason that politicians do nothing about the problem..."

I think the main reason is there is no obvious solution that maintains chances of getting re-elected. From what I see people just aren't interested in changing their lifestyles.

And outside my flat cars go back and forth, like they do every day of the week....

R Gates,

So it's a serious problem, agreed. But it does puzzle me why people are obsessing over those few outlier data points.

Scrub that, it doesn't puzzle me. The answer to the conundrum is this - there's rather a number of commentators on this blog who seriously expect a massive catastrophic outgassing, so they hang on every bit of data that might show it's happening.

So be it.

Lewis Cleverdon

Chris –
Many thanks for your very informative response above concerning GIC melt rates under the ‘resident’ Greenland summer high regime [GSH ?]. My apologies for implying that you’d identified a melt-rate inflexion point while intendedly referring to the meteorological one - brevity is double edged. My interest in the 2017 established outflow rise/yr is that it could show the influence of that new regime (as additional surface melt waters help glaciers’ bottom melt and lubrication) and thus give a clearer view of SLR timescale, so if and when you’d like to put up even a range of values they’d be gladly received.

The rate of outflow over the last decade appears to average a doubling roughly per 7 years (10.41% would be the precise exponent) which, IF maintained, would give two orders of magnitude increase of annual outflow by 2058. Given that this exponent could by my calculation clear the ice cap by around 2080 (to a large residual ice floe on a huge landlocked melt-lake) the prospect of its acceleration seems pretty dire.

I would strongly agree that there are feedbacks within feedbacks across the arctic – it could well be said that the feedbacks are inherently interactive, both internally and externally, on timescales including both immediate and up to several decades lagged. (One example of an ‘internal immediate’ interaction would be an ice sheet's albedo loss after a surface melting event due to the GSH regime leaving it more vulnerable to melting). The critical danger they pose in my view is their unrecognised diversity and potency – meaning, for instance, that the IPCC has given terrible advice to UNFCCC on sea-ice loss since 1992 – because the orthodox models it preferred failed to account the feedbacks and so by AR4 they ran about 1.8M km^2 adrift from observed change in summer ice extent.

As warming intensifies, the problem of current math’s inability to model multiple feedbacks, with random weather-event drivers contributing, will clearly be compounded by the emergence of unknown feedback mechanisms, whose formal recognition will require the years for research planning, operation and publishing, followed by the bizarre IPCC 5-year report cycle. As an example there is the plausible candidate R.Gates posited above of an unknown feedback in the reduced ice off northern Greenland (which had me puzzled) being the result of clockwise winds around the GSH. Three other candidates that are unpublished (SFAIK) that I’ve tripped over in browsing the issue are:

- the rising growth of shrubbery across the ex-permafrost tundra with its leaf-fall at summer’s end, much of which is then windblown until it falls into the increasingly prevalent thermokarst melt-pools and land-slip dam-lakes under the northward migration of rainfall, where it rots anaerobically and emits part of the carbon it collected as CO2 while growing as CH4.
- the emission of CH4 and CO2 from water bodies in melting permafrost driving a ‘taurus’ circulation of the water (if this term is new to anyone, think doughnut) as rising bubbles draw water up at the center to mix with warmed surface water before descending at the periphery to complete the cycle and deliver that warmth to the pool’s bed. Those who’ve used a diver’s air-pump will know the potential power of this dynamic.
- the power of a taurus circulation driven by a 1,000 metre-wide methane plume in the 40 metre seas of the ESAS has to be of a very different magnitude – it will not only draw in neighbouring warmed surface waters into its mixing and heat-transport dynamic, there will also be significant rotational currents helping to scour off seabed sediment to expose underlying permafrost and hydrates, thereby expanding the plume’s diameter and output.

Given the mathematical and institutional shortcomings in facing additional unknown feedbacks, I’d suggest that if cosmologists can respectably posit ‘dark energy’ to make sense of their data, then it is way past time that climatologists routinely included ‘URD-values’ in their modelling of observed ecosphere responses to warming – with ‘URD’ standing for “Unidentified Reinforcing Dynamics”. This isn’t actually a cop-out as it focuses attention on feedbacks’ research – and if the IPCC had required modellers to adopt it, then its AR4 prognosis of sea ice loss might not have been so disgracefully complacent. How would Copenhagen have gone if everyone had known that an effectively ice-free summer arctic was just seven years away ?



Artful Dodger

Thank you for sharing your ideas, Lewis. I think this direction must be the way forward for climatology.

BTW, did you mean a 'torus' circulation?

Thanks again for your insights!


Chris Reynolds

Hello Lewis,

I think it'll be into the 2020s before we can say anything about Greenland acceleration due to the 2007 shift, certainly I don't see evidence of it as yet. This change in atmospheric circulation may take a while to affect mass balance / run off significantly because of the long time constants involved. However in any case the correlations found by Hanna, whilst statistically very significant, are only of the order of 0.6, so it's far from a dominant factor.

With regards the idea of methane emissions from the ESS affecting ocean circulation. Someone here recently did a back of envelope calculation that showed the vertical mixing effect of current emissions was negligible. I'm not convinced there will be such a vertical mixing effect. Events like this years August storm and the increasing storminess of the Arctic coupled with loss of sea ice will have a much greater effect on stratification - much of which depends on salinity and temperature.

Actually I think the IPCC have done the only thing they could do w.r.t. ice sheet contribution to sea level rise. They had to make their conclusions as defensible as possible. Given the lack of success the denialists have had in questioning Working Group 1's Scientific Basis report, on which the Summary for Policy Makers is based, the IPCC's tactic of conservatism has worked.

IMO in the face of the uncertainties leaving ice sheet contribution out of the sea level rise calcuations was the correct thing to do. As more data comes in these estimates can be revised upwards, and they will.

Cosmologists are in a different position to climate science. They aren't facing an array of loonies, politically inspired deceivers, and paid liars. And they aren't producing a message that is unsettling to the core of our civilisation, a civilisation based on fossil fuel use.

As for sea level rise, I don't know. The IPCC range from AR4 was not a serious estimate. However be careful of applying doublings regardless of physical reality. There is research, forget who by, that finds the maximum feasible sea level rise by 2100 due to Greenland is of the order of two meters at most.


Sea level rise is a long term issue. The real problem is shown by David Archer's work on CO2 - our emissions will create a pulse of CO2, then we'll run out of fossil fuels, but around 25% of the CO2 will remain hieghtening atmospheric levels for well over 10,000 years. Add in the fact that we're going to see the permafrost melt and sub sea clathrates emit more methane and those two factors should keep methane levels topped up for centuries.

So once we start Greenland (And the West Antarctic Ice Sheet) off, they'll probably go almost entirely over the next two millenia. But Greenland won't be gone in 80 years.

Steve C

Chris and AJP
Thanks for illuminating the atmospheric chemistry that breaks down methane. I hadn't realized there was that much OH radical available in the atmosphere. But, on reflection, an oxygen-rich atmosphere+UV=potent oxidizing effects, indeed.

I gather, then, that this reaction accounts for the somewhat higher levels of C02 in the arctic, when there's a paucity of obvious CO2 production otherwise.

Perhaps the great risk of seabed methane, then, is not so much raising atmospheric levels dramatically. as depleting the arctic ocean of oxygen. All this methane only gets broken down with conversion of O2 to CO2, after all. Water has a fairly poor ability to keep oxygen in solution. So when the reaction happens in seawater, hypoxic dead zones could be created.

Perhaps we should be monitoring arctic seawater oxygen, as well as temps and salinity.

Given the critical importance of the arctic in delivering oxygen to the deep oceans worldwide, that process of oxygen depletion might be the great ecological catastrophe awaiting us from methane stores in the arctic.


Lewis Cleverdon

we share the view that circulation due to methane plumes is not of a scale relevant to overall oceanic mixing - I described it only as part of an internal immediate interaction accelerating the plumes' development.

WRT the IPCC's failure even to provide an updated track record of the mega-feedback's development, let alone to adopt URD-values for modelling that reflect published observations of responses to warming, it has worked to the extent of providing so bland a document that no government suffers any embarrassment by their lack of commensurate action.

In this sense IPCC scientists appear to have been co-opted into a system where governments have the veto on what science as a profession has to say about The existential threat to our society. Retreating from the necessary confrontation with US-sponsored denialism may be more comfortable for the secretariat (at least until that appeasement attracts its customary escalation of pressure) but it is not what is required of the scientific community in the present circumstances.

Concerning SLR off accelerating Greenland melt, I should be delighted to see any data either that a seven-year doubling is an overestimate, or that there is some factor by which GSH won't accelerate it, or that there is some factor to radically decelerate the output in the coming decades - the 2080 date for clearance is merely the logical outcome IF a 10.43% exponent were neither raised nor reduced, - and I'd be the first to agree the probability of its alteration.

On Dr Archer's overview I guess we may agree to differ, as it seems to me an odd mixture of defeatism and complacency. Defeatism in the idea that we'll use fossil fuels till they run out - and that must include both the vast coal reserves now accessible to coal-seam gasification as well as the potentially massive methane hydrate stocks, both of which are amenable to Gas-to-liquids conversion for liquid fuel supplies.
And complacent in the assumption that that warming generated by that level of fossil carbon emissions would not tip the seven interactive mega-feedbacks - that are already accelerating at 0.8C of warming - into an untenable mutual escalation of warming.

I part company with him on this view since it is becoming increasingly clear that while current climate destabilization is impacting global agriculture, allowing warming to rise above 1.5C is to invite serial global crop failures and the (heavily armed) geopolitical turbulence that would entail. Dr Archer's 'laissez faire' approach would appear to accept well over 6.0C. This I'd consider outright defeat.

That I guess is the core difference - having been engaged for several decades with the issue of mitigation, I remain fully confident of its feasibility, though neither the political analysis nor the mitigation strategy I serve are any part of the failed conventional wisdom.

Maybe Neven would consider setting up a page for the interface of science and global politics, where these matters could be thrashed out without intruding on discussion of the science.



Peter Ellis

Concerning SLR off accelerating Greenland melt, I should be delighted to see any data either that a seven-year doubling is an overestimate, or that there is some factor by which GSH won't accelerate it, or that there is some factor to radically decelerate the output in the coming decades


It's been calculated that more than a 2m sea level rise by 2100 is physically implausible (which is actually scientific language for impossible).

The key point is that almost all mass loss from Greenland occurs by calving glaciers, not from surface mass loss (i.e. melting). Surface mass loss is so negligibly small that even if you project forward the current increasing rates of surface mass loss and then increase all the numbers by a factor of 10, it still only contributes about 10cm of sea level rise from Greenland by 2100.

That being so, then the remainder of the sea level rise must be contributed by increased glacier flow rate. That is, mountains of ice collapsing into the sea, drifting away and melting in the warmer waters.

BUT - this hypothetical ice flow has to pass through the existing glacier outlets. There's mountains in the way everywhere else!

Running through the calculations, then to get 5m of sea level rise by 2100, the glaciers would need to flow at an average rate of 71.5 km/year. That's already an implausibly fast rate (~60 times current-day rates): if you consider the postulated exponential progress of the melt, then the peak glacier velocity would have to be four or five times higher.

The bottom line is that you just can't force ice through the glacial outlets fast enough to get more than ~1m of sea level rise by 2100. To get more than that, you have to do it by surface melt - and they've already accounted for 10 times more surface melt than expected.

Sea level rise shouldn't be a major issue for any but the most low-lying countries, at least not within the next century. The real worry from a human perspective is changes in weather patterns destroying food supplies.

Jim Williams

Peter Ellis: "It's been calculated that more than a 2m sea level rise by 2100 is physically implausible (which is actually scientific language for impossible)."

Can you supply me references for that from scientists which predicted this Summer's melt?

Peter Ellis

Why would you expect a sea ice expert to also be an expert on land ice glacier dynamics? I provided you a peer-reviewed reference from one of the the highest-regarded journals in the world. If you have better evidence, write it up and get it published.

Jim Williams

I'm interested in data reviewed science Peter, not in peer reviewed alchemy.

Greenland is not simply subject to glacial dynamics, and furthermore they've been totally wrong too. I was asking questions back in the 90s about the flow of glaciers after the collapse of restraining ice shelves and they were saying there'd be no significant response.

When it comes to people who say it can't, first tell me their predictive skill (just like we ask of hurricane models) then tell me what limits they claim upon the system. Don't bother telling me about their peers. I'm well aware of Thomas S. Kuhn's work. We aren't in a position to run the climate experiment over and over and do real Science. Anyone who says this or that will happen in the climate is a prophet, and I shall apply the rules for prophets -- if they get it wrong they are to be ignored.

Let's deal with this scientifically, and not be Scientismists.

In other words, any claim that "physically implausible (which is actually scientific language for impossible)" is to be viewed as bullshit until demonstrated otherwise.


James Hansen still argues 5m 21st century sea level rise is possible.


Very rapid sea level rise has occurred before e.g. At MWP1a about 14,500 years ago when sea levels rose 14-18m in 500 years or about 40mm a year !!!


Peter Ellis

Yes, and it's always been a puzzle as to how that could happen. Recently a plausible mechanism's been put forward based on the shape of the ice sheet

Greenland isn't that shape.

I'm getting increasingly depressed by the trend of commentors on this blog to ignore and denigrate published science and cling to whatever idea-of-the-moment seems most likely to prove catastrophic.

Jim Williams

The WAIS is the entire story. Everything else is a side show.

Go ahead and be depressed, as the "science" has been depressingly bad. Almost as bad as economics.

Peter Ellis

I agree the WAIS is the largest worry in the long term (most likely centuries to millennia).

However, I was answering a point specifically about the Greenland ice sheet, asking for reasons why a naive exponential extrapolation (i.e. all gone by 2080) might be wrong. I provided a link to the best available calculations, and a solid physical mechanism for why a simple exponential collapse isn't plausible.

If you have scientific, mechanistic objections to the findings of that paper, state them and justify them.

Jim Williams

I have a simple objection, but the field is the History of Science not Climatology. I see no reason to accept any projection which is of the form "it must" or "it cannot" in this field. There simply isn't a validated hypothesis upon which to base any such claim. Right now exponential extrapolation has just as much claim to validity as any reason offered that it might be wrong.

You are welcome to say that there are competing hypotheses which if correct would discredit expotential extrapolation, but please don't assert that there are any hypotheses which have been scientifically validated, as there are none.

This is alchemy, not science. By the time it becomes science we shall all be dead, if for no other reason, of old age.

It is the claim "x cannot happen" that I find unscientific. There's simply no way to (in)validate such a statement given our state of understanding. Not only that, but recent history makes such a statement politically extremely ill advised.



Hansen and Sato gave some objections to Pfeffer et al in the paper referred to above:

They say (pp.22-23):
"The kinematic constraint may have relevance to the Greenland ice sheet, although the assumptions of Pfeffer at al. (2008) are questionable even for Greenland. They assume that ice streams this century will disgorge ice no faster than the fastest rate observed in recent decades. That assumption is dubious, given the huge climate change that will occur under BAU scenarios, which have a positive (warming) climate forcing that is increasing at a rate dwarfing any known natural forcing. BAU scenarios lead to CO2 levels higher than any since 32 My ago, when Antarctica glaciated. By mid-century most of Greenland would be experiencing summer melting in a longer melt season. Also some Greenland ice stream outlets are in valleys with bedrock below sea level. As the terminus of an ice stream retreats inland, glacier sidewalls can collapse, creating a wider pathway for disgorging ice.
The main flaw with the kinematic constraint concept is the geology of Antarctica, where large portions of the ice sheet are buttressed by ice shelves that are unlikely to survive BAU climate scenarios. West Antarctica's Pine Island Glacier (PIG) illustrates nonlinear processes already coming into play. The floating ice shelf at PIG's terminus has been thinning in the past two decades as the ocean around Antarctica warms (Shepherd et al., 2004; Jenkins et al., 2010). Thus the grounding line of the glacier has moved inland by 30 km into deeper water, allowing potentially unstable ice sheet retreat. PIG's rate of mass loss has accelerated almost continuously for the past decade (Wingham et al., 2009) and may account for about half of the mass loss of the West Antarctic ice sheet, which is of the order of 100 km3 per year (Sasgen et al., 2010).
PIG and neighboring glaciers in the Amundsen Sea sector of West Antarctica, which are also accelerating, contain enough ice to contribute 1-2 m to sea level. Most of the West Antarctic ice sheet, with at least 5 m of sea level, and about a third of the East Antarctic ice sheet, with another 15-20 m of sea level, are grounded below sea level. This more vulnerable ice may have been the source of the 25 ± 10 m sea level rise of the Pliocene (Dowsett et al., 1990, 1994). If human-made global warming reaches Pliocene levels this century, as expected under BAU scenarios, these greater volumes of ice will surely begin to contribute to sea level change. Indeed, satellite gravity and radar interferometry data reveal that the Totten Glacier of East Antarctica, which fronts a large ice mass grounded below sea level, is already beginning to lose mass (Rignot et al., 2008).
The eventual sea level rise due to expected global warming under BAU GHG scenarios is several tens of meters, as discussed at the beginning of this section. From the present discussion it seems that there is sufficient readily available ice to cause multi-meter sea level rise this century, if dynamic discharge of ice increases exponentially."

I don't know if their criticism of Pfeffer et al is correct, but in any case I haven't seen a rebuttal yet. Also the potential rate of SLR seems even more important than the amount of SLR at a certain date. Even if 2 meters of SLR around 2100 would be the maximum, then the rate of SLR at that moment could be about 5 meters/century.

Recently Meehl et al published estimates of upper limits of about 6 meters of SLR around 2200 and about 12 meters around 2300:

It would be nice to know what Pfeffer and colleagues think of that.

Patrice Monroe Pustavrh

@Peter Ellis: I'm getting increasingly depressed by the trend of commentors on this blog to ignore and denigrate published science and cling to whatever idea-of-the-moment seems most likely to prove catastrophic.
I agree with you on this one. However, it is sometimes difficult to grasp 1 or 2 deg C change in temperature, as temperatures vary by much more with weather. But in reality, it is dangerous. For me, the following picture works fine:
- This year we had about for heat waves here in Slovenia, nothing special, nothing dramatic, although there has been some drought reports (it was large drought but as far as I can recall, not the worst one). Let's say that during one of these heat waves the daily max temperatures were 32, 33, 34, 34, 35, 36 and 36 deg C. Now, this is a little bit uncomfortable, but not unbearable. Now, I just added two degrees of predicted warming for each day for same heatwave and tried to imagine, how this same heat wave would look like - the temps would be 34, 35, 36, 36, 37, 38 and 38. Now, this is much more uncomfortable - you can live without air conditioner when temps are bellow 35, but above 35, it is bad (and yes, plants do not have air conditioner). I think people do not realize that weather, which was a little bit extreme yesterday, it will become normal in the future. I think this is what people must somehow understand.


Thanks Peter I hadn't seen the Gegorie et al paper, I'll take a look.

I strongly agree with your point about the importance of keeping to the published research.

I too have been concerned by the attitude of some commenter’s who say that because the science has under predicted the rate of arctic melt that we should just ignore it.

If we begin to denigrate the science that's been done and rush off with our own speculations then we're no better than the climate deniers we're always criticising.

The science is bleak enough without having to imagine some nightmare scenario.


Also since we're talking about the possibility of rapid sea level rise, what do you make of this paper?


I was particularily struck by a piece at Phys.org which carried an interview with the lead auhor which said:

"If water were to warm by about 2 degrees under the ice shelves that are found along the edges of much of the West Antarctic Ice Sheet, Marcott said, it might greatly increase the rate of melting to more than 30 feet a year. This could cause many of the ice shelves to melt in less than a century, he said, and is probably the most likely mechanism that could create such rapid changes of the ice sheet. "


Jim Williams

There has been lots of good science done on what the current climate is, and how it is currently changing.

But the the predictive work...which isn't science unless you can repeat it...has failed badly. As we can see by comparing the science with the prophesies.

Go ahead and make the same mistake the deniers make in your own way.


Once the arctic is ice free it should begin to absorb and store heat energy. Has anyone seen a model that deals with effects on Oceanic circulation and specifically on North Atlantic Deep Water formation? The few I have come across deal with the meridional overturning during cool climate periods. NADW formation in the Norwegian Sea helps to keep Europe warm. I wonder what a model based on NADW formation inside the arctic basin would look like?

Lewis Cleverdon

Peter -
thanks for your response above. I would fully agree that the impacts on global farm yields are the proximate threat - specifically to maintaining the global coherence essential to continue effective mitigation of the climate problems we've engendered.

My interest in Greenland SLR is as a potentially early component exacerbating the food scarcity issue by flooding destitute coastal city people into the farmlands of many vulnerable nations - But what I wrote about the present doubling period of outflows clearing the GIC by 2080 was in no way a prediction, but was qualified with both tense and an 'IF the exponent was maintained' phrase. While there are plausible sources of acceleration of the current output, I've yet to see those of its deceleration, and hence my question.

The paper you posted was not news to me though it was good of you to put a link to it. The reason I don't find it cogent is that it assumes that natural landforms will constrain an accelerating glacier, rather than simply slowing it while a dam is built and then allowing greater velocity after it has burst. The physical aspect I thought under-explored in the paper was the quality of ice after it is temporarily retained by such a dam, with surface melt water infiltrating and rotting it.

It was about a decade ago in the Caucasus that one such glacier dam burst, allowing the pent up volume to sluice down the valley covering over 50kms in about two hours, wiping out even the topsoil, let alone the villages. This was a surprise to Russian glaciologists as the dam had been considered stable.

In this light I think I'd back the glaciers to find a way through or over obstructions, not least by the reduction of their viscosity under diverse factors including the GSH, ice-surface albedo decline, increasing rainfall events, and a greatly rising incidence of Greenland earth tremors.

Apart from the prospect of an effective albedo restoration program being applied over the arctic, the one wild card negative feedback I've seen that could hugely affect the GIC melt is the possibility of global mass-balance changes accelerating the ongoing rise of vulcanism with its cooling emissions. Prof Bill McGuire is adamant that this is under way, albeit at a minor scale - and he has the remarkable professional accreditation of running Vulcanism Risk Research for the major global re-insurance firm, Munich Re, meaning that he is entrusted with advising on hundreds of billions worth of risk.

On balance I'd suggest that, with PIOMAS projections being confirmed, we'd do well to respect the findings of those scientists whose work incorporates the influence of the diverse feedbacks, and regard those whose work still ignores them as more partial indicators of probable outcomes.

Hoping this clarifies my position somewhat,




@Peter Ellis & Patrice Monroe Pustavrh: I'm getting increasingly depressed by the trend of commentors on this blog to ignore and denigrate published science and cling to whatever idea-of-the-moment seems most likely to prove catastrophic.
Let us remember a few factors. Granted, before any properly done paper is published it must be peer reviewed, but the reason for the publication is not only to disseminate knowledge, but also to test it rigorously to see if it indeed holds up. If you take a look at all the papers ever published most fail to hold up on all points and some even collapse quite spectacularly. That does not mean they should come under ridicule, but it does mean that no paper should be treated as though it gets things right until proven so. WRT ice, it is obvious that still very little is understood as to all that is involve in melt or growth. Right now we are on a very steep learning curve and it does not take a very big leap to consider that when the majority of experts 10 yrs ago were declaring that the Arctic could not melt out before 2100, getting that very wrong, that we must consider that Greenland and the Antarctic are in much greater danger then the majority of experts may realize at this present time.
It is blogs of quality such as this that the experts can thrash out ideas and explore new ways of looking at things.


OT I know: There is even a need for the uneducated on blogs such as this. An example is Alexander Graham Bell was known to like to be with little kids that asked the why question. His comment on that was that sometimes his greatest discoveries and inventions came as a result of actually trying to fully answer those very questions.


And to return to our business, first persistent snow cover at Svalbard.

That is, the Ny-Ålesund on the Northern island of Spitsbergen.

Chris Reynolds


"Defeatism in the idea that we'll use fossil fuels till they run out "

That bit isn't Archer, it's me, it's what we'll do.

It's not defeatism, it's pragmatism. You'll note this is a view I rarely voice because I don't want to get in the way of whatever chance we have of reducing fossil fule use. But I see no practically achievable way of doing it.

The one way out is to crack fusion. If we do that then it will probably remain out of affordability of the poor nations - the price of fossil fuels will collapse because the demand drops, and the poor will use up what's economically retrievable for them. While emissions from the rest of the world drop as fusion rolls out.


"The main flaw with the kinematic constraint concept is the geology of Antarctica..."

But we're talking about Greenland.

Pfeffer's kinetmatic constraint could be wiggled upwards, but the principle remains - the orography of Greenland is such that continuing doublings are not going to happen. No argument can be made against this statement.

Perhaps Hansen is right, but again the difference between 2m and 5m in terms of the process is just wiggle room. However I recently read a paper I can't put my hands on now - IIRC it showed that during the rise out of the last glacial it was the icd sheet in the ocean that went rapidly, that on land went at a more leisurely pace in response to insolation increases.

Ah yes - Carlson & Winsor, 2012, Northern Hemisphere ice-sheet responses to past climate warming.

During the last two deglaciations, the southernmost margins of land-based Northern Hemisphere ice sheets responded nearly instantaneously to warming caused by increased summertime solar energy reaching the Earth. Land-based ice sheets subsequently retreated at a rate commensurate with deglacial climate warming. By contrast, marine-based ice sheets experienced a delayed onset of retreat relative to warming from increased summertime solar energy, with retreat characterized by periods of rapid collapse.

So we can expect Greenland to go at a pace commensurate with GHG forcing, while we can expect surpirses from Antarctica.



Carlson and Winsor also say (at the very end):

"The rate of radiative forcing also needs to be considered with these palaeo ice-sheet analogues. The increase in boreal summer insolation and rise of 90–100 ppm in atmospheric CO2 during terminations occurred over ~11,000 years (Fig. 2). In contrast, human carbon emissions have increased atmospheric CO2 by over 100 ppm in less than 200 years, with even greater increases predicted to occur in the coming century98. Given this more rapid rise in greenhouse gas radiative forcing, Earth’s remaining ice sheets could respond in a manner not previously observed in the late Quaternary."

I think that's also the point Hansen is making: the forcing is much stronger/faster now than it was in the past, so sea level could very well also be a lot faster than most scientists expect today.

The other point is about the rate of SLR: even with only 1 meter of SLR around 2100 the rate could be about 3 meters/century. So what rate of SLR can our societies still realistically adapt to, and for how long?

The 'wiggle room' you're talking about may make the difference between, say, 2-3 m/century of 5-6 m/century, depending also on how much mitigation we'll prove capable of.

And Hansen's doublings won't continue indefinitely (if at all): he expects a negative feedback of iceberg cooling to stabilize or slow the process at a certain point.

Another relevant question for adaptation is how gradual or abrupt the rate of SLR will change over time. I agree that West-Antarctica will probably be more suprising than Greenland.

Lennart van der Linde (The Hague, Netherlands)

Steve Bloom

"No argument can be made against this statement."

Chris, I'm recalling the recent revolution in the consensus view of land permafrost melt and thinking you're being a little too definite here. The ice loss signal is being transmitted to the center of the GIS, and those kinematic constraints won't mean much if some form of collapse takes place in the ice streams such that a mix of water and smaller chunks of ice begins to flow out. It would be interesting to ask Mauri what the thinking is among glaciologists in this regard, although I don't know if he'd be willing to discuss it openly.

Steve Bloom

Just to add regarding past deglaciations that forcings today are quite different what with black carbon deposition and rapidly warming water adjacent to the ice.

Account Deleted

Aren't the GIS ice temperature too low to see that sort of thing happening i.e. GRIP (Fig 1a) temps seem to range from -30C at the surface to -10C close to the bedrock

Artful Dodger

"fossil fule use" -- lol, the mind wobbles:

- 'fossil fool'
- 'fissile fools'
- Camp Century, Greenland.


Account Deleted

There have been other that have suggested that the GIS is going to turn into a big slushie and collapse, but they haven't really shown where the heat is going to come from to raise 2,850,000 cubic kilometres or so of ice up to slushie temperature.

Mauri has previously comment on another site "I have spent plenty of days on glaciers when the temperature was in the 70s and meltwater is running everywhere, and the ice we were on was plenty strong. Drop an ice cube in a glass and the ice does not disintegrate into shards. The glacier on Eyjafjallajökull did not just turn into a slurry despite this massive heat-induced meltwater running over and through the Gigjokull Glacier"

Account Deleted

Viscoelasticity is different from slushiefication

Jim Williams

Steve Bloom, Chris has a habit of overstating his case. He needs to learn the qualified language used in the literature.

Clearly, the one thing that can be said definitively is that our knowledge at this point doesn't allow any unqualified statements about global warming.


Jim you seem to not understand how right glaciologists have been: look at the post on Pine Island Glacier I wrote some time ago at Realclimate, the response of this glacier was forecast decades ago. Jakobshavn was a focus 25 years ago focus because we were concerned other glaciers would accelerate in the same manner that it already was flowing, and this has happened. This weekend I noted the change in terminus conditions on Thrym Glacier and predicted what would happen as a result. We had no idea what the timing would be but we understood the mechanics of what would happen.

Jim Williams

Glacierchange.wordpress.com, I was corresponding with glaciologists when they discovered how Pine Island was behaving. I'd been asking how the glaciers would respond to the climate changes of the 80s (in the early 90s) and their response was "not much." Then it suddenly changed to "we'll get back to you."


Jim you were talking to the wrong people. The experts in our field on glaciers such as Pine Island and Jakobshavns were right on. I attended several glaciology conferences between 1983 and 1986 where this was a key focus. The when was not known, the what was why we were gearing up to monitor PIG and Jakobshavn This is partly what spurred me in 1983 to start my now 29 year research project to observe the changes in North Cascade glacier due to climate change.



Thanks for stopping by. Could you comment on the discussion referred to above between Pfeffer et al and Hansen and Sato on the kinematic constraints of melting GIS and WAIS? What is your take on Hansen's concern of a risk of more than 2 meters of SLR this century and potential rates of SLR of about 5 m/century after that?

Lennart van der Linde

Jim Williams

You may be right Glacierchange.wordpress.com. Glaciers have been a strong secondary interest of mine ever since I watched the Nisqually recede up Mount Rainier in the 60s as a kid, but I picked computers rather than climate as a profession.

I do know that the person I was talking to at the time did a rather abrupt about face. That probably wouldn't have happened if there hadn't been a competing theory on ice dynamics.

Fact is, I still see a lot of predictions based upon the discredited "slow change" hypothesis being touted as unalterable law. So it wouldn't surprise me to find glaciologists who still thought the ice flows couldn't destabilize the WAIS.


To date all of the changes we have seen in our glaciers and ice sheets fit our understanding of their dynamics. The timing of the onset of changes has been faster and more widespread than any of us anticipated, but the actual dynamics fit very well. There is a difference between understanding the general dynamics and being able to accurately model and ice sheet. An example we knew that the underneath fast flowing ice stream of WAIS and Greenland had plenty of water at the base and adding more meltwater would not really increase flow much. The idea of meltwater lubrication as a big important dynamic change for marine terminating GIS outlet glaciers did not really fit. Some people lost track of this but the research has again demonstrated this through the lack of seasonal velocity, the greatest velocity change being at the calving front, not where meltwater increased, and the lack of acceleration of non-marine terminating glaciers where meltwater would also play a role. This does not mean introducing basal meltwater into areas where it is limited will not have an impact. In 1987 I helped edit a paper by T.Hughes on the "Ice Dynamics and deglaciation models when ice sheets collapsed". that reviewed many key concepts of ice sheet weakness that we have seen playout. Pfeffer et al (2011) did a nice job of reviewing the history of the glaciologic communities approach. In the end Hansen and Sato do not offer any specific dynamic processes by which a faster ice sheet loss could play out, and their argument for the high end just does not fit ice sheet dynamic understanding.

Climate Changes

@Steve C

Pleasure :)

Someone posted this link elswhere (http://science.nasa.gov/science-news/science-at-nasa/2012/07aug_meteorsmoke/) in which NASA confirms that the mystery water comes from Methane. I'm glad that this has been confirmed as I've been following the pesky NLC's for two seasons and CH4 did seem like the culprit all along.

However, larger, more intense NLC's only occur because more water is available and at 80km and H2O, just like CH4 does, gets a good beating by solar radiation splitting the molecule and freeing Hydrogen. Increase in atmospheric CH4 is hardly a fantasy now and widely expected and, if it behaves like the other symptoms of GW then it will be exponential too.

If hydrogen was released into the atmosphere, because of the law of thermodynamics, we could reasonably conclude that it would have to reach the same temperature, and same energy as the air around it. That said, its velocity would have to be substantial enough to allow it to have the same kinetic energy as the surrounding air. Now with that in mind consider that hydrogen is the lightest of all atoms…it’s miserably lacking in mass, in fact its 1/16 the weight of oxygen. So in order to come to the same energy it has to move incredibly fast, so fast it actually has a velocity significant enough to escape the pull of earth’s gravity. Over time due to the average velocity that allows hydrogen atoms to exceed earths escape velocity of approximately 25,000 mph frequently enough that eventually the majority of hydrogen has escaped our atmosphere and because of this Hydrogen is scarce on Earth in its elemental form.

After release from a molecule, some Hydrogen will re-combine but a % will scape to space to be lost for good. There is one other place we know of where 1H (protium) is completely gone but 2H (deuterium) remains as a tell tale sign that Hydrogen was abundant. I'm talking about Venus of course where it is believed that a runaway global warming boiled the water away, got split in the higher atmosphere and the Hydrogen just flew away. No Hydrogen (1H) to combine with O means no water. Levels of Deuterium (2H) and Ozone (O3) have been detected in Venus's atmosphere to confirm this.

I'm aware of the planetary differences between Earth and Venus and I'm not suggesting that we will lose all Hydrogen (and therefore all water) soon but it is likely that we could end up like Venus if anthropogenic global warming is not abated soon and eventually stopped.

Seke Rob

Considering that Earth has been several degrees warmer than present and for a long time, and water is still here, I'd not worry on that front for a longer while... Maybe the next incarnation of HSS will.

The comments to this entry are closed.