Are scientists conservative about sea ice?

An interesting entry on the NSIDC Icelights blog (hat-top to GreenOctopus) that I also indirectly discussed a couple of months ago:

Are scientists conservative about sea ice?

Guest post by Walt Meier, NSIDC Scientist

Arctic sea ice set a record minimum extent in September 2012, far below the previous record low in 2007. Summer extents have been far lower than average for the last decade, with several record or near-record years. Looking at the numbers, one is tempted to think that the Arctic Ocean may reach nearly sea ice-free conditions within just a few years. But most expert analyses indicate that we’re likely at least a couple decades away from seeing a blue Arctic Ocean during the summer.

So what is going on here? Readers have asked if scientists are being too conservative in their assessment of the recent ice loss. We asked Walt Meier, NSIDC scientist, to address this question. Following is his response.

Conservative science, or complex systems?
Scientists by their nature tend to be conservative when viewing new evidence. While the recent years have been surprising, most scientists are not willing to accept that ice-free conditions are imminent. But that is not because they’re being too conservative. The Arctic sea ice system is complex and there are many aspects that are not yet well understood.

A variety of feedbacks promote ice growth or ice loss. For example, sea ice has a high albedo, meaning it reflects the sun’s energy back into space. Darker ocean water has a low albedo, meaning it absorbs more of the sun’s energy, and thus more heat. As sea ice extent decreases, the change in albedo spurs a well-known feedback that enhances summer melt because the ocean absorbs more of the sun’s energy than the ice.

Likewise, there are also negative feedbacks that will slow the loss of ice. One of these results from the fact that ice grows more rapidly when there is no ice or thin ice than when thick ice is present under the same air temperatures. Thus in fall when the sun goes down and the atmosphere gets cold, open water areas grow ice quickly allowing such regions to “catch up” to thicker ice regions. These feedbacks and many other factors, such as ocean and air temperatures, wind, and weather patterns, prevent an easy assessment of a complex system.

Read the rest here.

Image caption: The U.S. Coast Guard Cutter Healy encountered only small patches of sea ice in the Chukchi Sea when this photograph was taken on July 20, 2011. (Courtesy NASA Goddard Space Flight Center)

Comments

[Villabolo]

Is there a thread listing all the predictions for an ice free Arctic by those who post here? It would be interesting to see who has what opinions.

[jmp473]

Science must have a basis in established facts so in that sense it expresses conservative values but science is also about exploration and new ideas which are concepts that do not express conservative values. The problem today is the rate of change.

Science has never had to deal with such dire circumstances happening so quickly. On the plus side scientists have unprecedented technological advances at their disposal. The peer review process, which is crucial to science being science, should be able to be speeded-up. Increased funding should be able to be allocated... but scientists are only human and while most (imho) have an altruistic streak a mile wide, a few, and it seems often in the most powerful positions, would choose self aggrandizement over saving the world... sadly a most human trait. Too, those that hold the purse strings are rarely even scientists at all and in some crucial instances are diametrically opposed to new discovery. So human... and again that is what may be our greatest stumbling block to solving the problems we humans have created for ourselves. So, it isn't that science is so conservative... it's that conservativism is unable to keep pace with the rate of change.

[Hans Gunnstaddar]

That's a great idea Villabolo. I 2nd the motion.

[Paul Beckwith]

Notice that Walt Meier does not discuss the PIOMAS sea ice volume exponential decline that has been basically substantiated by the Cryosat measurements.

This is a significant oversight on the part of the NSIDC since this data is the main reason for projections of sea ice vanishing with the next 3 years or so.

In my opinion, not addressing this PIOMAS/Cryosat volume trend basically invalidates the NSIDC article.

[LRC]

In defence of scientist they are trained to not to believe anything another scientist claims unless they themselves can duplicate it. They problem with global ice melt is that any claims can not be duplicated and therefore the fall back possition is to be conservative.
A late 20th example was a claim that fractals could explain main things in science. It took a few years for mathematicians to be convinced that it was more then just a computer program that produced these strange designs. And new it has been discovered that if you take a branch of a tree in the middle of a forest, it will show you that shape and strength of the forest it is in.
I have been wondering if a mathematician could create a fractal formula that could give you the exact conditions of the Arctic currently just by studying a small portion of the Arctic.

[Shortfatape]

Anyone else notice the time period for the observations in the graphic accompanying the full article? Looks like they're only showing observations through 2010 - which makes the model forecasts look relatively more accurate.

[Fairfax Climate Watch]

The single negative feedback that's chosen, is one of the greatest reasons for concern: once the sun vanishes and conditions favor heat loss from the ocean, the ice quickly returns to seal in the ocean heat...so yea. I'm not sure that's exactly doing the ice any favors.

[Fairfax Climate Watch]

oh, and the ice doesn't grow quite so thick or fast when heavy snow falls on it soon after it forms.

[Fairfax Climate Watch]

In the context of the transition from perennial to seasonal ice cover, the sea ice growing back quickly once the sun goes away is not a negative feedback at all. And that is the context of the article. Fast refreeze promotes a worsening ice condition by preventing heat loss. It also promotes snowfall as it crimps heat flow from the ocean up to the air column. And that snow is highly insulating and inhibits further ice thickening.

[Jai Mitchell]

Julienne Stroeve NSIDC

January 2011

"Arctic will probably become ice free in summers sometime in the next couple of decades"

http://www.youtube.com/watch?v=X6cIDXGg-xY&t=1m30s

September 2012

"I think there are a few scientists that probably are reconsidering how quickly the arctic may go ice free, I know that Peter Wadhams and Weislaw Maslowski both are sort of on the extreme end of that. so, some time before 2020 are their estimates. I still think its, you know, the reality is that we can't predict the weather and its certainly possible that natural climate variability can bring back the ice."

http://www.youtube.com/watch?v=vwdnqWL1YkY&t=4m10s

March 28, 2013

"When we look at future projections of what is going to happen they are all indicating that within the next few decades we could see an arctic ocean that may be completely ice free in the summer time."

http://www.youtube.com/watch?v=2xwZNfiuJTE&t=1m26s

This is the inherent caution in the scientific debate for those who study the arctic. For those who rely on those studies to perform climate models will pass that uncertainty into the models and, if they are wrong will produce significant errors carried forward in their future warming scenarios.

[Mtough]

I found the article a tad underwhelming, that's rare for NSIDC which does cover the science very well. It's audience is pretty broad nowadays so they seem to try and keep it simple, to some extent, but this really did deserve a tad more depth.

I agree they should have addressed PIOMAS and the 80% reduction in volume between 1979 and 2012 and it does look as if 2012, at least, is not included in the graphic.

It would be interesting if Walt Meier could add to the discussion here - I just Goggled him and he has done a couple of guest posts on WUWT but we won't hold that against him - I know many posters here have fought the good fight and ended up grey or bald in the process.

This years weather and lack of conducive melt conditions have changed the dynamic a little - back to conservative. Only marginally and there's still 6 odd weeks to go but with so much less insolation north of 80N this year (I'm sure someone here could calculate it) to still be running fourth in melt really shouldn't turn back the dial too much. The fundamentals are the fundamentals but the climate modellers didn't predict 2007 or 2012 so the feedback mechanisms are still biased to melt - we just don't know conclusively what they are. Well - rotten Ice, lack of MYI etc., etc. but you get the drift. Speed of change seems to be the key though, in a process that should be geological, anthropological Climate Change has the arctic snorting some really weird white stuff and it ain't snow.

[Jai Mitchell]

It seems like the NSIDC is being more conservative because they were originally surprised by the 2007 melt, thought that it was a fluke, then equally surprised by the 2012 melt, figured it wasn't a fluke but didn't (and still don't) really understand it and now have a 2013 melt that looks pretty ok, even recovering except it is acting like a melt season has never acted before, it is too different and they still don't understand it, so cannot really say and are hedging their bets.

I remember when people started blaming 2007 on black carbon. . .just grasping at straws if you ask me.

[manuphonic]

In this context I have a question for Paul Beckwith or any of you. The recent Arctic sea ice volume loss rate that Walt Meier inexplicably fails to address in the Icelights interview ... the loss rate that appears closer to exponential than to Gompertz in many eyes ... the rate charted by PIOMAS & validated by Cryosat-2.... What mechanism, neglected or underestimated by the extent models that Meier cites, do you suppose is driving this ice thinning at such a recently high rate?

[Neven]

manuphonic, I think increased ocean heat flux is a good candidate.

[dorlomin]

To anyone who thinks science is too conservative there is an easy solution.

Do your own research and publish it.

[dorlomin]

I remember when people started blaming 2007 on black carbon. . .just grasping at straws if you ask me.

Good luck with telling Jason Box that his dark snow project is grasping at straws.

[Climate Changes]

@dorlomin

The Dark Snow Project is all about Greenland,... Jai Mitchell's comment is about the Arctic Sea Ice. Here's an apple, here's an orange... compare and contrast two round objects.

[GeoffBeacon]

Dolomin

Can "research" be looking at data derived from satellites and seeing that the CMIP5 models are wrong?

Could "research" be asking climate modellers about feedbacks missing from their models and being told "Yes. They are missing?"

Is it "publishing" to inform readers through this blog?

[Werther]

Dorlomin, please,
You’ve been with us for a very long time. In fact, I think you joined as soon as neven started the blog. Maybe in your opinion this bunch has become too pessimistic or uninformed or whatever. But could you stop the oneliners and convince us through specific reasoning?

[Climate Changes]

In regards to the article, yes, all scientists but a few have been conservative, possibly for fear of ridicule. I can tell you from my own experience as a well informed amateur that in 2005, when I started seriouly discussing the future decline of the ASI with others, I was told a few times to get a tin foil hat. Since I had no professional reputation to lose I wasn't that bothered about being ridiculed, and in the end I was proved correct.

There are many disciplines involved in observable AGW, biology, glaciology, climatology, physics, maths,... etc, each with its own specialist scientists and many studies from each field screaming fast changes. So perhaps there hadn't been brought together soon enough hence conservative results?

[Fufufunknknk]

@Dorlomin

Chamberlain, arguably, took the conservative position. Conservative != good science. Often correlated, perhaps, with good science, but not the same as.

Similarly, in regards to the comment "Do your own [non conservative] research and publish it", it is a bit like trying to prove that meat tastes good by asking vegitarians to try it. Perhaps you meant "Create your own community, create standards for those communities that work given the needs of science, create your own journals, do your own research and then publish it."

For what it is worth, I think that science is both too conservative and, at the same time, very trendy. Perhaps that is the same thing though.

[L. Hamilton]

Are scientists conservative about sea ice?

That could be an empirical question, I think. My crowd-source posts here point toward one way we might ask it, by comparing sea ice predictions of scientists with real sea ice but also with each other, and with the predictions made by non-scientists such as participants in this blog -- as all of us learn from the world.

This year's data certainly will not be definitive, but by October they should give some new perspective. In the meantime, I'd encourage anyone who has ideas about this year's ice to post their own numerical predictions to the Crowd Source thread -- for NSIDC mean September extent, in the first line of your post.
http://neven1.typepad.com/blog/2013/07/foo.html

[Physicist Retired]

Are scientists conservative about Arctic sea ice? Yes. Scientists are also conservative about estimating the speed of plant/animal migration away from the poles, the rate of climate-change-induced extinctions, permafrost melting, and a whole host of other phenomena.

jmp (above) identifies one part of the problem here - the rate of climate change is incredibly fast. The Scientific Method and peer review, on the other hand, impose a more conservative bias.

Climate predictions, like the rate of Arctic sea ice loss, are based on models. But models are imperfect, and many of the mechanisms driving rapid loss of sea ice are too poorly understood to incorporate into those models at all.

How rapidly will the upper layer of the Arctic Ocean warm - and by how much? At what rate will Arctic air temperatures rise (thus increasingly changing precipitation from insulating snow to ice-melting rain)? How will reduced sea ice alter atmospheric patterns and systems in the Arctic Circle (a question Neven has raised several times now)? Etc.

We may know these things are happening, but we have far too little data to accurately model them.

Scientists know that 'an abrupt and persistent change in [Arctic] sea-ice dynamics' occurred in 2007.

http://www.the-cryosphere.net/7/275/2013/tc-7-275-2013.pdf

They just don't know (precisely) why. Models don't show it. Models, instead, show many paths to 'stable' states (and even recovery), but not 'rapid and persistent' change.

The good news here is that some (new) research recognizes the fact that models and observational data are incompatible - and that observational data should be included in sea ice predictions even when the models say something completely different.

Here, for example, is the Abstract from Overland and Wang (2013). I apologize in advance for the long quotation, but I think it's an important one:

"The observed rapid loss of thick multiyear sea ice over the last 7 years and the September 2012 Arctic sea ice extent reduction of 49% relative to the 1979–2000 climatology are inconsistent with projections of a nearly sea ice-free summer Arctic from model estimates of 2070 and beyond made just a few years ago.

Three recent approaches to predictions in the scientific literature are as follows: (1) extrapolation of sea ice volume data, (2) assuming several more rapid loss events such as 2007 and 2012, and (3) climate model projections.

Time horizons for a nearly sea ice-free summer for these three approaches are roughly 2020 or earlier, 2030 ± 10 years, and 2040 or later. Loss estimates from models are based on a subset of the most rapid ensemble members.

It is not possible to clearly choose one approach over another as this depends on the relative weights given to data versus models.

Observations and citations support the conclusion that most global climate model results in the CMIP5 archive are too conservative in their sea ice projections.

Recent data and expert opinion should be considered in addition to model results to advance the very likely timing for future sea ice loss to the first half of the 21st century, with a possibility of major loss within a decade or two."

http://www.climatopoly.com/wp-content/uploads/2013/06/NOAA-Ice-Free-Summer-Arctic-2013.pdf

That, to me, is an astounding statement. I can think of very few times in the history of science when rapid change (with very serious consequences) outpaced our understanding - and scientists were therefore forced to give weight to data that they couldn't explain.

In the case of the Arctic, then, we may very well find ourselves in the position of watching science remain continually behind the curve - because the rate of change far outpaces our ability to understand how all the moving parts combine to create the phenomena we're actually seeing.

At least, that's what I expect to see in the near term.

[Lars Kaleschke]

"Millikan measured the charge on an electron by an experiment with falling oil drops, and got an answer which we now know not to be quite right. It's a little bit off because he had the incorrect value for the viscosity of air. It's interesting to look at the history of measurements of the charge of an electron, after Millikan. If you plot them as a function of time, you find that one is a little bit bigger than Millikan's, and the next one's a little bit bigger than that, and the next one's a little bit bigger than that, until finally they settle down to a number which is higher. Why didn't they discover the new number was higher right away? It's a thing that scientists are ashamed of - this history - because it's apparent that people did things like this: When they got a number that was too high above Millikan's, they thought something must be wrong - and they would look for and find a reason why something might be wrong. When they got a number close to Millikan's value they didn't look so hard." (Feynman, 1997)

from http://www.columbia.edu/~jeh1/mailings/2012/20121226_GreenlandIceSheetUpdate.pdf

Seems to be a related phenomenon

[Fufufunknknk]

If had my druthers, I would really like to see all scientists, as part of their phd, be forced to do at least one project where they start from first principles and derive the theory/experiment/ etc.

This whole basing things on literature and standing the shoulders of giants gets gamed into academic tiddliwinks.

But the issue here isn't an academic one about having a career based on trendy articles that are forgotten 5 years later, it is about, when faced with serious consequences, the moral obligation to publish the range of outcomes and make clear how limited 95% is.

[Henry1]

@M Owens

I think you are wrong on the "new sea ice growing back quickly is not a negative feedback".

If we take the alternative option, which is sea ice NOT growing back quickly and seeing more open water, then we have even thinner ice by the time next summer comes around which allows even faster melt and more area of open water by the minimum. Hence, faster regrowth of sea ice in the autumn is definitely a negative feedback because its preventing us from seeing earlier meltouts the next season. It sort of puts a "cap" on how thin the first year ice is the next season. Obviously the first year ice will eventually become thinner as winters keep warming and refreeze eventually takes longer, but right now, we haven't really seen a definitive jump in date when the refreeze begins. Its still almost purely driven by insolation.

[Vergent Bill]

"Climate models indicate that sea ice will decline more slowly than recent observations."

http://neven1.typepad.com/.a/6a0133f03a1e37970b017744cf5360970d-pi

http://i.imgur.com/rTztq27.png

The NSIDC article is incredibly deceptive, you would think that we just had a couple of bad years(2007 & 2012). The graph they used obscures the observed in model runs that show false extents well below 6M in the 1900-2000 era. Its like they threw a tantrum and scribbled on the graph with a crayon.

Vergent

[David Appell]

Paul Beckwith wrote:
Notice that Walt Meier does not discuss the PIOMAS sea ice volume exponential decline that has been basically substantiated by the Cryosat measurements.

Even the PIOMAS group does not predict an summer ice-free Arctic until the mid-2040:

"Arctic sea ice response to atmospheric forcings with varying levels of anthropogenic warming and climate variability,"
Jinlun Zhang, Michael Steele, Axel Schweiger
Geophysical Research Letters
Volume 37, Issue 20, October 2010

http://onlinelibrary.wiley.com/doi/10.1029/2010GL044988/abstract

[Jai Mitchell]

perhaps the fear of media bias and losing credibility produces self-censorship.

http://pus.sagepub.com/content/19/2/240.abstract

Self-censorship and science: a geographical review of media coverage of climate tipping points

[Jai Mitchell]

not sure if this is exactly on topic but wanted to share it, just came out.

http://phys.org/news/2013-07-ice-free-arctic-winters-amplified-pliocene.html#nwlt

Ice-free Arctic winters could explain amplified warming during Pliocene

[Steve Bloom]

David, I think that study has been superseded by reality, noting the PIOMAS results of the years subsequent to that study. The abstract states in part:

If SAT increases 4°C by 2050, summer ice volume decreases to very low levels (10–37% of the 1978–2009 summer mean) as early as 2025 and remains low in the following years(.)

I'm eyeballing from overall plots since I can't find summer mean figures, but didn't PIOMAS volume drop into the upper end of that range in 2010 and remain there since?

[Steve Bloom]

This recent paper (public copy) addressed the conservative bias in climate science head on (title/abstract):

Climate change prediction: Erring on the side of least drama?

Over the past two decades, skeptics of the reality and significance of anthropogenic climate change have frequently accused climate scientists of "alarmism": of over-interpreting or overreacting to evidence of human impacts on the climate system. However, the available evidence suggests that scientists have in fact been conservative in their projections of the impacts of climate change. In particular, we discuss recent studies showing that at least some of the key attributes of global warming from increased atmospheric greenhouse gases have been under-predicted, particularly in IPCC assessments of the physical science, by Working Group I. We also note the less frequent manifestation of over-prediction of key characteristics of climate in such assessments. We suggest, therefore, that scientists are biased not toward alarmism but rather the reverse: toward cautious estimates, where we define caution as erring on the side of less rather than more alarming predictions. We call this tendency "erring on the side of least drama (ESLD)." We explore some cases of ESLD at work, including predictions of Arctic ozone depletion and the possible disintegration of the West Antarctic ice sheet, and suggest some possible causes of this directional bias, including adherence to the scientific norms of restraint, objectivity, skepticism, rationality, dispassion, and moderation. We conclude with suggestions for further work to identify and explore ESLD.

[Neven]

Volume 37, Issue 20, October 2010

Oh, come on, this is almost 3 years ago! We're not discussing continental drift here, things go a little bit faster than that.

[Jai Mitchell]

Wipneus has an excellent series of graphs here: https://sites.google.com/site/arctischepinguin/home/piomas

The only graphic that even comes close to projecting zero volume in 2040 is this one, and that is by far the worst fit to the curve.

https://sites.google.com/site/arctischepinguin/home/piomas/grf/piomas-trnd7.png

[JackTaylor]

Is it conservative if scientists predict "essentially free" or "nearly free" - "qualifying to <1Mkm2" on a time-frame of 2016 +/- 3 years?

And other scientists predict free in mid 2040's to 2100, are they saying without any ice (zero) or for example, less than ten percent?

Seems as if the question needs a better definition before accepting all answers.

If the ride is not exciting (fast) enough and the throttle is "wide-open", did the person that asked the question on NSIDC Icelights elicit a "sucker answer"?

IMHO, still not enough (data) information to expect a firm answer.

[Shared Humanity]

Lars Kaleschke

It's interesting to look at the history of measurements of the charge of an electron, after Millikan. If you plot them as a function of time, you find that one is a little bit bigger than Millikan's, and the next one's a little bit bigger than that, and the next one's a little bit bigger than that, until finally they settle down to a number which is higher. Why didn't they discover the new number was higher right away?

It is called "anchoring bias" and is a universal human trait.

[Shared Humanity]

They have done studies to verify "anchoring bias".

One study involved a group of people who were asked to estimate the number of jelly beans in a glass jar, each voicing their opinion. The first one asked had been prepped to offer an obviously low number. The remainder of the people would, in turn, raise the number in steps, always seemingly careful not to move too far above the previous number. The average of the group was always significantly lower than the actual number.

A second group did not involve a plant but allowed each person to suggest the number freely. The group average was always closer to the actual number of jelly beans.

[Physicist Retired]

Regarding "Arctic sea ice response to atmospheric forcings with varying levels of anthropogenic warming and climate variability"

I think it's important to understand that this study used data ending in 2009, and projected forward from there. In 2009, the researchers had one 'outlier' to work with (2007) - and treated it as such.

You can access the entire paper here:

http://psc.apl.washington.edu/zhang/Pubs/Zhang_etal_2010GL044988.pdf

Notice Figure 1, page 2 (especially (e - volume), but also (d - extent)). The 'expected recovery' of ice in 2010 is quite noticeable in those graphs. Results from then on will be highly skewed towards longer timeframes for an ice-free Arctic.

Of course, just 4 years later, we have far more 'interesting' data. One wonders what Zhang et al would look like if it were recalculated today.

[LurkyMcLurkerson]

I'm not sure that "conservative" is really the point, for all the back and forth. I mean, I suppose they could more often make personal statements, give educated opinions that are theirs, but that has long been a tricky business.

The whole foundation of science rests on assuming that the data knows more than you do -- not trying to make it intuitive, because much of science is really not all that intuitive. Ask anybody working with quantum mechanics.

You learn not to trust your intuitions unless you can find backing for them. You go off the data and the math that you have.

Yeah, they leave PIOMAS out of this, and that's a little problematic, but the point really is -- how comfortable are they making statements that aren't directly backed by solid data?

The problem with avoiding anything else here is that you have to also have reason to think that your data is giving you the information you're actually looking for, addressing the questions you want it to address. It's _true_, but only within its own design and methodology limitations, and each statistical(etc) manipulation hones some meaning but loses other meanings. Is the data we have telling us what we need to know? I lack that confidence now. It might be. But I'm not sure it is.

And a solid point actually gets accidentally made above. If I wonder stuff about the data we have, how likely am I to be able to get the funding to actually collect the relevant data and publish something? I'm not. Even if I were active in this field, and even if I could wrestle the funding somehow, it'd still likely take years to collect and process, since we're talking about things that matter much more on an averaged plane than on an instantaneous one.

So every conjecture, even a reasonable one, is really a hanging question. Nobody can answer it. I have enough background to know that it's often at least not a _totally_ stupid question, but I can make conjectures but I can neither confirm them nor rule them out. There isn't data.

And scientists are very uncomfortable with conjecture, as they should be -- except that so much hinges on this, and except that their statements, based only on the current data and a few models that may or may not be capturing things well, will maybe (probably) turn out to have been grossly incorrect. Because data looking back and ending at the current has a terrible time with major sea changes (pun intended, maybe).

Sometimes it feels to me like what we're really doing is standing by and collecting the fading pulse so we can use that when the thing is already dead. But what else can science do? It needs the measurements, it needs to maybe put them into models that have no "control world" to compare them with, only the one we live on, which is changing rapidly.

So we're left with the data we have, and with a scientific community that hates to comment much beyond that, and models that are almost certainly wrong even if they're useful.

[Chuck Yokota]

Scientists aren't in the business of making predictions; their goal is understanding the mechanics of how the physics operates in the system. Putting in statistical fudge factors without a theoretical basis may make models more closely reflect observational results, but add nothing to the goal of understanding the system, and the usefulness of any projections into the future becomes speculative. Real world concerns may push them into issuing warnings based on their educated judgment, but they should not be forced to give them the imprimatur of science if the theoretical basis is not there.

[NeilT]

The NSIDC has been giving warnings for years about "tipping points". Yet nobody ever admits a tipping point has been reached.

The missing Volume data are a case in point. If you look at Extent and only Extent then look at the weather and other factors, then 2008 - 2012 makes no sense.

However if you look at the step change which happened in volume in 2007 and then overlay it on 2008 to 2012, it all makes sense.

Because for all the statements of "Ice Recovery" mechanics, volume never recovered from 2007. In fact it continued to fall.

So models based on ice mechanics of thicker ice will not work in a world of thinner ice.

I expect, with 20:20 hindsight, 2007 will eventually be designated as a tipping point event for Arctic Ice.

[David Appell]

To check Zhang et al (2010) that I referenced above: I took the PIOMAS daily sea ice volume and calculated its 1978-2009 summer mean, with summer taken as June 21 - Sept 21.

The average was 19.35 Kkm3. The results for subsequent years, as a percentage of this mean value, are:

2010 39%
2011 36%
2012 33%

which are already in the range of "10-37% as early as 2025" their model predicts, though faster than the model, assuming I defined "summer" as they did and I haven't made any errors.

Of course, it's also possible the model is wrong, for either future projections, past volumes, or both.

Zhang et al (2010) write that the future rate of melting it expected to slow down:

"The projected annual mean ice volumes decrease substantially during 2010–2025.... They decrease at lower rates in later years, particularly over 2030–2050 (Table 2) even as SAT [surface air temperature] continues to increase. One reason is that, although ice melt mainly in summer continues to increase with increasing SAT (Figure 3c),
thermodynamic ice growth mainly in winter increases too (Figure 3b) because thinner ice has a higher growth rate [Bitz and Roe, 2004]. In fact, the linear increasing trends of annual mean ice growth over 2010–2050, like those of annual mean ice melt, are comparable to the trends over 1978–2009 (Table 2). Another reason is that ice export from the Arctic decreases in the future, just as in 1978–2009 (Figure 3a and Table 2), because of reduced ice thickness (Figure 2) [Holland et al., 2010]. As a result, the linear decreasing trends of the net ice change (ice growth minus ice melt and ice export) in the Arctic are small, especially with A2 and B2 (Table 2), leading to much lower trends in decreasing ice volume during particularly 2030–2050 (Table 2)."

[Chris Reynolds]

David Appell,

With reference to fig 1e of the Zhang paper: I've often found myself wondering if the inflection at the point where projection starts suggests a non passive atmospheric role. If I recall correctly for the future weather they use randomly ordered NCEP/NCAR yearly data with the warming trend added.

Anyway, thanks for reminding me of that passage about the reason for a slowing of loss rate.

[Neven]

Copied from the ASIF:

I want to add another two cents, the last ones because I'm too busy, so have to move on.

I don't mind scientists being conservative (like I said, I've become more conservative and reticent myself since I started blogging because I know my limits and feel responsible for the ASIB's credibility), but I do have problems with the way some of them sometimes communicate. It's almost as if they're eager to dispel any worst case scenario that might pop up, and they pop up a lot because there are things happening in the Arctic that nobody saw coming, and the Arctic is an incredibly important factor in keeping things stable for the Northern Hemisphere. My guess is that they fear the fake skeptic drums, as fake skeptics have been so successful at intimidating scientists, eating them up as it were, as if they're cannibals. And so our beloved scientists walk through the jungle and say: hush, hush, lest the cannibals hear us and start beating their drums to warn each other of our presence. ;)

I understand all of this, but still, I don't understand why they can't put worst case scenarios in perspective AND at the same time emphasize that there are potentially very serious risks involved with Arctic sea ice (and summer snow cover) loss. Something along the lines of: "Arctic sea ice loss could very well have, and perhaps already is having, serious consequences. The trends are very clear and have been dropping much faster than anticipated. Combine this fact with our lack of knowledge and thus relatively large uncertainty, and it's clear that there's a distinct possibility of unpleasant surprises occurring. HOWEVER, in the case of methane burps, there is no or very little direct evidence that such an event could take place in the near future. We don't see it in paleoclimatic data or in the field. Yet. Given the risks, we need to increase our knowledge on this subject so that we can constrain uncertainty and determine what the worst case scenario could look like."

I've just re-read Walt Meier's piece and you just don't see anything of that, except towards the very end, very weakly in the last sentence: "One thing that all scientists who study sea ice agree upon is that under increasing temperatures, the overall long-term declining trend will continue and some summer in the future, we will look down on the North Pole and see a blue Arctic Ocean. It’s not a matter of if, but when." Ah, so that's the consequence? A blue Arctic Ocean? Well, that doesn't sound too bad! Reminds me a bit of the Bahamas! Mind you, I'm a fan of Walt Meier and think he does a very good job practically all of the time, but his piece only tells half the story.

Never mind the really subjective stuff by folks like Andy Revkin and Jason Samenow who really seem to get a kick out of bashing the alarmists. Unfortunately, their arguments are full of holes and they fail to emphasize that the combination of the rate of change, lack of knowledge, bad track record so far for predicting events in the Arctic, calls for a lot of caution and increased research. They will say: "Oh, but I just said that last week in another piece". And I say: "No, you have to say it every time, because that's the story of the Arctic. Tell the whole story, every time."

There, that's what I wanted to say. Back to building now.

[Robertscribbler.wordpress.com]

I don't blame NSIDC for its conservative stance or cautious assessment. I also appreciate the broader model range to account for different scenarios. But that doesn't mean we can't broaden our understanding of a complex system that is swiftly deforming due to a number of outside forcing and feedbacks by challenging convention.

If we lean too much on conservatism, we will continue to be surprised by 'outlier' years like 2007 and 2012. In such cases, any counter trend year looks reassuring. But they're just noise interrupting what, since 1979, has been an ongoing melt signal.

And, as many mention above, PIOMAS does seem to show this signal most clearly. If we are not to see melt by or before 2020, we will have to see a change in trend. So, for my part, I'd like to hear a reasonable explanation as to why a nearly 35 year trend would markedly change. We know there are negative feedbacks. But what feedbacks are strong enough to beat back that trend? The insolation switch doesn't seem a great candidate to me. What about Greenland melt? How much does that affect the ice dynamic? And how does PDO affect the sea ice? Do we see melt acceleration during negative PDO as the oceans deflect heat northward?

For my part, I think it would be useful to ask the question -- how can we reasonably expect the sea ice to survive to 2030, 2040, or 2050? Scenarios, that explain assumptions, might help as well.

As for 2013... Could be a counter trend year. We'll see. But it's not over yet.

[mps]

I'm generally a huge fan of this blog and its posters. However, the bulk of the comments to this post sound like something out of the denial-sphere: Quick dismissal of the scientific consensus, claiming one is much more credible than the experts because you eyeballed a graph and extrapolated it, creating a strawman by ignoring important points (E.g., Walt Meier's observation that the models predict occasional large downward spikes but that revert to the long-term trend, so having years like 2007 and 2012 is to be expected), quick dismissal of studies that go against the beliefs of the forum, etc.

It is perfectly possible for climate scientists to be wrong and for non-climate scientists to identify that, so we absolutely should be challenging Dr. Meier's post.

At the same time, full-time climate scientists (Note: I am not a climate scientist) have an incredibly deep understanding of climate issues informed by wide-ranging knowledge of the data and its suitability for statistical inference. The point I stop reading a "skeptical" blog is when it dismissively claims to have overturned the main body of scientific belief based on a simple one-sentence refutation as if climate scientists were idiots.

While there have been some comments here that engage the thinking of the scientific community, many IMHO casually dismiss it rather than constructively challenging it, which is what I'd expect on WUWT. It feels very out-of-character for the posters here.

[LRC]

Then you get those like in Canada that unless they say exactly what the government in power wants them to say, they will not get any funding and will be blacklisted.

[Henry1]

@mps

Agree wholeheartily with most of your post. I have been lurking here for a couple years and just started posting earlier this season, and it seems that we've seen many uncharacteristic posts recently. Not just in this thread, but several others. I don't know if its because the severity of last year's melt got a lot of us over confident on the science, but to be frankly honest, many in here sound like the deniers. So much time is spent laughing at denier blogs like WUWT which is easy to do at times like last year. However, I'm not sure how many realize that our prediction from this site has a great chance to be a laughing stock at the end of the season while denier blogs like WUWT end up way closer on their predictions.

It doesn't mean they are correct in their "science", but what it does mean is that we need to look at ourselves in the mirror and reevaluate how much science we actually preach on this blog. Perhaps we don't know nearly as much as we thought a year ago.

Science is extremely humbling and I'll never fault scientists for taking a more conservative approach when the amount of uncertainty is as great as exists in arctic sea ice.

[Neven]

So much time is spent laughing at denier blogs like WUWT which is easy to do at times like last year.

Let's not exaggerate. Other than that I agree with much you and mps say, though not with everything.

Different strokes for different folks.

[toby]

Henry,

I'm not sure how many realize that our prediction from this site has a great chance to be a laughing stock at the end of the season while denier blogs like WUWT end up way closer on their predictions.

I also lurk here with distinction, but cannot remember any instance of laughter at inaccurate predictions. Every year has had its lemons, and I don't think anyone is worried.

What did draw snorts of derision, justifiably IMHO, were specious claims of a a full scale "Arctic Ice recovery" in 2008 and 2009.

[Villabolo]

Below is a sampling from Steven Goddards "Real Science" site. If they ridicule us we can just link them to this jewel:

Terra Incognita says:
September 3, 2011 at 10:57 pm

[Steven Goddard said:] “New ice is starting to form in the Arctic, and it looks like 2011 has a possibility of becoming the shortest melt season (time from peak to minimum) on record. Longer polar melt seasons are a fundamental tenet of global warming theory.”

[TI replies:]I see. The shortest melt season on record will give us the second smallest ice extent on record. That’s a lot of melt for such a short season. I guess the shorter them der seasons get the more ice will melt. (We could use some animated laughing smileys).

Reply
Steven Goddard says:
September 3, 2011 at 11:08 pm
You missed the part about MYI doubling over last year and quadrupling since 2008.

http://www.real-science.com/shortest-arctic-melt-season-record#comment-49617

[fryingpan136]

@Villabolo
When I clicked on the link I was redirected to a porn site. Perhaps it is just my ipad, but I am suspicious about the link.

[Villabolo]

@Fryingpan136:

"When I clicked on the link I was redirected to a porn site."

Yikes!!! It works perfectly for me on IE 7, Firefox, Google Chrome and Safari. Try another browser.

[Kevin McKinney]

"When I clicked on the link I was redirected to a porn site."

Denier porn, by any chance?

[wili]

Isn't the main scientific point of doing modeling exactly to see where they go wrong so that we can figure out how to make better models...

Far from disrespecting scientists, asking what went wrong with the models and why is exactly the right scientific question to pose.

And if all the models have been getting further and further from where reality seems to be going, it is surely time to ask if there is some larger tendency in the attitude of the researchers or in something else that would cause such a widespread misreading of the direction of events.

Just my $.02.

[Congratulations, this was comment number 30,000 on the ASIB; N.]

[Susan Anderson]

Please don't link to denier sites and focus on their nonsense. Plenty of that elsewhere.

I was looking for a place to put this Earth Observatory gem, and suspect this is not it, but since I'm here:
http://earthobservatory.nasa.gov/IOTD/view.php?id=81736

"Heat Intensifies Siberian Wildfires"

[P-maker]

Susan,

you have a point there. Burning the permafrost like this ought to go under a separate headline: "Absurd impacts".

Neven,

please also consider opening a thread at some time on the forthcoming third Persistent Arctic Cyclone (PAC-C Aug13)

[John Christensen]

@M.Owens,

Yes, agree that the 'feedback' of fall freeze is questionable.

Ice is basically a lid on the ocean, and once the lid is there, it quickly diminishes the heat exchange between water and air in the fall/winter season, the same way that the ice dimishes heat influx from sun radiation during spring/summer.

What adds to the complexity is that sun radition is at max at solstice, where the ice cover is still relatively high, and that the ice cover is near minimum 3 months later, when impact from sun radiation has been significantly reduced. So is the heat intake during spring/summer higher than heat outflux during fall/winter??

[LurkyMcLurkerson]

There's much above I agree with. I will say that even understanding this whole "science" dealio pretty well, it sure does get frustrating to feel like we're all standing around awaiting more data, while each set of data we get over time (and across all fields) feels like it's pointing pretty darn clearly to "wow, this is going to suck for humans."

But I'm not sure that's a problem for scientists, I think that's a problem with policy and culture. How much clear data do we need to finally friggin' act? Meanwhile, it's not like we're upping tons of science funding all over the place so that we can get better data.

On the rest: I don't really make predictions, I'm more enthralled with the mechanisms underlying. But I figure it makes sense for people to make them here. I also think that worrying too hard about what the "weird neighbors" will think is probably pointless. They'll think what they think. I have found many posters here -- and certainly Neven himself -- to be very clear on the fact that none of us are sure what the heck is going on in any one season, regardless. Predictions at our level here are really a way to test our ideas and see how various factors seem to be playing out.

Being wrong in the end shouldn't be a source of shame. It is entirely possible to be wrong for the right reasons, and it is entirely possible to be right for totally stupid and irrelevant ones.

I don't really care what the denialists think. Their potential mockery over some people here winding up wrong is about 8,000,000,000,000th on my list of concerns.

[Fairfax Climate Watch]

in this BBC video: http://youtu.be/rg8ISGnQwU0 a scientist says "the models that project ice-free summers by 2030 are conservative." It's a very good all-around video too.