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What Role Did the Arctic Storm Play in the Record Sea Ice Minimum?

Posted on 19 October 2012 by dana1981, Albatross

With 2012 shattering the previous minimum Arctic sea ice extent record by more than three quarters of a million square kilometers, climate contrarians have predictably been scrambling to find an excuse why the Arctic death spiral is still nothing to worry about.  The Arctic storm which first hit on 05 August 2012 has been used as a convenient scapegoat. This despite the fact that the evidence indicates that most of the long-term loss of Arctic sea ice is human-caused.

Can this single storm really be responsible for breaking the previous Arctic sea ice record by such a large margin?  The short answer is no.

Sea Ice Decline Prior to August

Since the Arctic storm first hit on August 5th, we can first evaluate its impact by looking at the state of the sea ice extent leading up to that point.  For example, the average July sea ice extent in 2012 was the second-lowest on record, just slightly behind 2011 (Figure 1).

July sea ice NSIDC

Figure 1: July average sea ice extent, data from the National Snow and Ice Data Center (NSIDC).  July 2012 had a lower extent than 2007, and the second-lowest July average extent behind 2011.

According to JAXA, as of August 4th, the 2012 Arctic sea ice extent was also the 2nd-lowest on record, behind only 2007.  2012 and 2007 were also essentially tied for the largest sea ice decline between early June and early August (2011 having less June-August ice loss because its extent in June was already low) (Figure 2).

JAXA extent to Aug 4

Figure 2: Arctic sea ice extent from 01 January to 04 August, for 2003 through 2012, data from JAXA.

Thus we see that Arctic sea ice in 2012 was experiencing substantial decline even before the Arctic storm hit.  

Comments from Arctic Experts

Several Arctic sea ice experts have weighed in on the record-breaking minimum in 2012 and the effects of the summer storm on this record.  According to NSIDC Director Mark Serreze,

"The previous record, set in 2007, occurred because of near perfect summer weather for melting ice. Apart from one big storm in early August, weather patterns this year were unremarkable. The ice is so thin and weak now, it doesn't matter how the winds blow."

NSIDC scientist Walt Meier said,

"...in the context of what's happened in the last several years and throughout the satellite record, it's an indication that the Arctic sea ice cover is fundamentally changing....The Arctic used to be dominated by multiyear ice, or ice that stayed around for several years.  Now it's becoming more of a seasonal ice cover and large areas are now prone to melting out in summer."

Dr. Julienne Stroeve (another NSIDC scientist) said,

"The acceleration of the loss of the extent of the ice is mostly because the ice has been so thin. This would explain why it has melted so much this year. By June the ice edge had pulled back to where it normally is in September,"

"The 2007 record was set when you had weather conditions which were perfect for melting. This year we didn't have those. It was mixed. So this suggests the ice has got to a point where it's so thin it doesn't matter what the weather is, it's going to melt in the summer. This could become the new normal"

NSIDC Arctic sea ice news and analysis:

"Other than the August storm, the pressure pattern in 2012 does not appear to have been as favorable in promoting ice loss as was the case in 2007, and yet a new record low occurred."

Claire Parkinson, a climate scientist at NASA Goddard Space Flight Center said,

"The storm definitely seems to have played a role in this year's unusually large retreat of the ice.  But that exact same storm, had it occurred decades ago when the ice was thicker and more extensive, likely wouldn't have had as prominent an impact, because the ice wasn't as vulnerable then as it is now."

Paul A. Newman, chief scientist for Atmospheric Sciences at NASA's Goddard Space Flight Center estimated that there have been about eight storms of similar strength during the month of August in the last 34 years of satellite records - one every 4 to 5 years.

How Strong was the 2012 Storm?

While the 2012 Arctic storm was a strong one, as Newman noted, it was not unprecedented.  To confirm Newman's claim, we examined daily surface pressure maps from NCEP-NCAR and NCEP-II DOE reanalysis data.  Low pressure systems are typically associated with a tight pressure gradient that results in strong surface winds.

In the 34 years between 1979 and 2012, we identified 19 deep low pressure systems (defined here as having a central pressure less than 980 hectopascals [hPa]) in the Arctic between 15 July and 15 September.  Most of these deep lows occurred over the Barents, Laptev, and Kara seas, so they are not suitable analogs for the 2012 storm.

However, there were nine previous storms during this timeframe in the same general area as the 2012 event.  Of these, we identified five best analogs for the 2012 event. These occurred in 1980, 1990, 1991, 1994, and 1997 (Figure 3 - click for a larger version).

arctic storms

Figure 3: NCEP/NCAR sea level pressure maps in (from right to left and top to bottom) on 07 August 2012, 28 August 1980, 12 September 1990, 06 August 1991, 17 August 1994, and 03 September 1997.

What Effect Did Similar Previous Storms Have on Sea Ice Extent?

If this type of deep Arctic storm has a major influence on annual Arctic sea ice minimum as claimed by contrarians, then we would expect to see similar declines in 1980, 1990, 1991, 1994, and 1997.  Let's see what the data shows (Figure 4).

storm extents

Figure 4: September Arctic sea ice extent data from NSIDC (blue), years with Arctic summer storms similar to the 2012 storm are depicted in red.

There was a decrease in September Arctic sea ice extent from 1989 to 1990 and 1996 to 1997 (and of course from 2011 to 2012), but an increase from 1979 to 1980, from 1990 to 1991, and from 1993 to 1994.  With half increases and half decreases in September Arctic sea ice extent during one of these summer Arctic storm years compared to the prior year, there is no clear sign that these storms had a big impact on sea ice extent.

We should also note that the Arctic storm in 1990 occurred on 12 September, just days before the annual minimum, and there was very little sea ice decline between 12 September and the minumum that year.  Thus the 1990 storm cannot be responsible for most of the sea ice decline between 1989 and 1990.  In fact, there wasn't a particularly large decline between the date of any of the Arctic storms and the annual minimum, with the exception of 2012. 

Figure 5 shows the change in sea ice extent at the time of the summer storm (left frame) vs. the annual minimum (right frame) for each of these years (note that the year in the date on the right frame in Figure 5 is cut off - the year is the same as in the left frame).

storm differences 

Figure 5: Arctic sea ice extent maps on the date of each summer Arctic storm in 1980, 1990, 1991, 1994, 1997, and 2012 and at the annual minimum each of these years.

Thus in the five previous examples of summer Arctic storms similar to that in August 2012, there was no clear impact on the final Arctic sea ice minimum.

Additionally, Screen et al. (2011) found that it was the frequency of cyclones between May and July, and not those in August or September, that are responsible for conditioning the sea ice in September for either a significant loss or gain over the previous year.

So What Factors Contributed to the 2012 Record?

As the ice experts mentioned above, the 2012 summer storm very likely made an already bad situation worse.  The reason is that because of the long-term decline and thinning of the Arctic sea ice in response to the dramatic warming, the ice pack is now very vulnerable to events that would have historically had little or no impact.

Not only does the earlier retreat of the sea ice result in a positive albedo feedback, it also means that when there are storms such as in 2012, the winds are capable of generating large swells that can penetrate hundreds of kilometers into the pack and break up the sea ice, thereby hastening the decline.  Figure 6 shows the long fetch (the distance along which the winds are able to interact with the ocean surface and produce wind waves and swells) available to winds during the 2012 storm.  These conditions were ideal for generating large swells.

Figure 6:  Wind field (coloured arrows, with warm colours representing strong winds) and sea ice (grey areas) on 9 August 2012. Credit: NASA/Goddard Science Visualization Studio

A similar event was witnessed by Canadian scientists aboard an ice breaker in the Beaufort Sea in early September 2009 (Asplin et al. 2012).  They observed swells over 250 kilometers (km) from the ice edge following  the transit of two lows across the Arctic Basin in short succession. The large swells caused the breakup of large (>1 km) multi-year ice floes up to 5 meters thick, into much smaller floes (100-150 meters).  On that occasion the long stretch of open water was also key in permitting the storms to generate a large swell.

Peer-Reviewed Literature on Arctic Storms

We might also ask whether these summar Arctic storms have become stronger and/or more frequent, and if so, why?

Hakkinen et al. (2008) analyzed the wind stress data from the NCEP/NCAR reanalysis to test for a change in Arctic storm intensity/frequency and found that summer storms are becoming more intense (Figure 7).

Hakkinen fig 3

Figure 7: Trends of the NCAR/NCEP Reanalysis wind stresses for 1948–2006 for (a) annual, (b) winter, and (c) summer values.  Units are 10-4 N/m2 per year.  Figure 3 from Hakkinen et al. (2008).

The authors conclude that the increasing Arctic wind stress trend in the summer has higher significance than the winter trend due to enhanced storminess.

"Our results show a gradual acceleration in sea ice drift over the 50 years analyzed. The accelerating trend in the central Arctic is present both in winter and summer observations, with nearly equal statistical significance. Since the atmosphere is responsible for the main forcing of the sea ice, the obvious conclusion is that the increased sea ice speeds relate to increased storm frequency and/or intensity."

Long and Perrie (2012) investigated the impacts of increased open water in the Beaufort Sea for a summer Arctic storm in 2008 using a coupled atmosphere-ice-ocean model.  They found that a reduction in ice cover and more open water results in stronger Arctic storms.

"The model simulations suggest that the lack of ice cover in the Beaufort Sea during the 2008 storm results in increased local surface wind and surface air temperature, compared to enhanced ice cover extents.... These changes result in enhanced surface winds, by as much as ∼4 m/s during the 2008 storm, compared to higher ice concentration conditions (typical of past decades)."

Screen et al. (2011) found no significant trends in late spring or summer Arctic cyclone frequency over the period 1979–2009.  So it appears that the intensity of summer Arctic storms may be increasing due in part to the reduction in sea ice cover, which is primarily human-caused, but there is no clear indication of an increase in Arctic storm frequency.

Peer-Reviewed Literature on the Long-Term Sea Ice Decline

As noted above, the long-term thinning and decline of the Arctic sea ice allowed the 2012 summer storm to impact this year's record minimum.  Thus it's also important to note that there is very strong evidence in the peer-reviewed literature that the long-term sea ice decline is primarily human-caused.  For example, Day et al. (2012) concluded,

"despite increased observational uncertainty in the pre-satellite era, the trend in [Arctic sea ice extent] over this longer period [1953–2010] is more likely to be representative of the anthropogenically forced component."

Stroeve et al. (2012) concluded,

"Based on the CMIP5 multi-model ensemble mean, approximately 60% of the observed rate of decline from 1979–2011 is externally forced"

While Notz and Marotzke (2012) found very poor correlation between oceanic cycles and sea ice extent, but very good correlation between CO2 and ice extent (Figure 8).

notz fig 4

Figure 8: Correlation between September sea ice extent and CO2 forcing (red), solar forcing (blue), PDO index (green), and AO index (yellow).  Figure 4 from Notz and Marotzke (2012).

And based on the results of Vinnikov et al. (1999), there is less than 0.1% probability that the long-term decline in Arctic sea ice extent is due solely to natural variability.

Summary

The 2012 summer Arctic storm simply cannot be blamed for the record-shattering Arctic sea ice extent minimum. 

  • Arctic sea ice extent was already declining rapidly prior to the storm formation, to the second-lowest level on record.
  • The scientific literature shows that the Arctic is undergoing a fundamental change, with the remaining ice continually becoming thinner, weaker, and more vulnerable, and that this decline is primarily human-caused.
  • Sea ice experts agree that unlike in 2007, the 2012 Arctic weather conditions were not ideal for melting ice, and while the the summer storm played a part in the record minimum, it was not the main cause.
  • In the past, Arctic summer storms similar to the 2012 event did not have a major impact on sea ice extent or September sea ice minimum.
  • The 2012 record-breaking minimum can be attributed to a number of factors.  The summer storm likely played a role, but primarily because the ice was thinner, weaker, and less extensive to begin with than in prior years due to its long-term human-caused decline.
  • The scientific literature indicates that Arctic storms may be becoming more intense, in part due to increased open water as the sea ice continues its long-term human-caused decline.

Note: this post has been incorporated into the rebuttal to the myth Arctic Storm Caused the 2012 Record Sea Ice Minimum

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Comments 1 to 50 out of 73:

  1. What Role Did the Arctic Storm Play in the Record Sea Ice Minimum?

    Here are a few questions I can’t help but ask that come from the heading: Comments from Arctic Experts

    NSIDC Director Mark Serreze is quoted as saying,
    "Apart from one big storm in early August, weather patterns this year were unremarkable. The ice is so thin and weak now, it doesn't matter how the winds blow."

    How does he qualify “unremarkable” and can he empirically prove that “it doesn’t matter how the wind blows”?

    You quote SIDC scientist Walt Meier saying,
    "... Arctic sea ice cover is changing....large areas are now prone to melting out in summer."

    Isn’t it true that Arctic sea ice has always been a seasonal phenomenon with highs in the winter and lows in the summer? Is it not the nature of ice to go through cycles of melt/freeze, a kind of “changing” as temps rise and fall?

    Claire Parkinson at NASA Goddard Space Flight Center said,
    "The storm definitely seems to have played a role in this year's unusually large retreat of the ice.”
    She appears to disagree, and if there is disagreement between the Arctic Experts…


    Do you see what I did there? Snip, clip, and disregard the bulk of your offering that details actual science in favor of misquoting Experts who I’ve extracted from context and then asking questions that are plausible yet remain fallacious; questions that give the appearance of being reasonable. The battle is over more than just the facts, science and understanding. After all, I am not trying to convince you or those who do the research and publish the papers; you are all in the minority. I’m going after the hardware store owner who won't check the quote to see if I left something out, the wheat farmer who is great with his hands but not with science text books, and that guy on the subway who reads the WSJ and is worried that his portfolio might take a hit anytime someone suggest AGW is real.

    Your article is excellent by the way and I appreciate your efforts and synopsis of our current status.
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  2. Yubedude,
    While you've done a great job of illustrating the methods of the denialist mob, I don't think much can be done about it. If you're hoping scientists will or can modify their language to stop people from doing such things, I think it's asking the impossible. About all that can be done is to educate people who are interested in truth and hope enough take interest to spread the word.

    Truth, especially in complex matters with political implications, is always at a disadvantage. Thanks to Skeptical Science for providing us with so much of what is needed to do the job.
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  3. Very interesting to see how all the factors interact.
    [pedantry]
    The large swells caused the breakup of large (>1 km) multi-year ice flows up to 5 meters thick, into much smaller flows (100-150 meters).

    I think 'flows' should be 'floes'?[/pedantry]
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  4. Doug @3 - thanks, fixed.

    YubeDude @1 - there's not much we can do about climate deniers quote mining, as we saw during Climategate. All we can do is put the quotes in the proper context when that happens.
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  5. After reading the article I still have this question:

    If the storm had not have occurred, would we still have had that minimum ice extent?
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  6. Dale, like extreme weather, AGW loads the dice. A good storm could have happened last year and produced similar result. The continued warming means multi-year ice is gone so each bad summer chips away at it. Will next year be lower yet? Probably not. But another big low will happen the next time the weather dice throw bad. Just like you can bet that the next record breaking global temperature will happen with an El Nino rather than in a La Nina year.
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  7. scaddenp @6
    Sorry, but that's not really an answer to my question.

    If the storm had not have occurred, what would the minimum sea ice extent be?
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  8. If you are genuinely interested in the answer, head over to Neven's and go through the threads from early August to see what the predictions were - people posted a variety of predictions using a variety of methods. Or check the SEARCH outlooks, which include predictions from experts and amateurs (you may want to weight them by their past reliability, see Dana's review here). Or take the data and make your own hindcast starting from before the storm.

    It seems to me that volume would certainly have set a new record, and it is more likely than not that NSIDC, CT and Bremen would also have set records even ignoring anything we know about declining thickness and ice age.
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  9. I will do a naive comment : maybe calculating and showing the daily/5day average rate of loss of sea ice [i]area[/i] and [i]extent[/i] would be useful for the discussion ? From my (limited) understanding, we should see that the storm did not have a very strong impact on sea ice area (ice is covered by water during the storm, thus fooling the sensors, but reappears thereafter) and a stronger impact on extent.
    I did not do the calculations, nor I am knowledgeable in Arctic sea ice. I did not see anything on neven's blog about loss rates (but I didn't search that hard).
    Just thinking aloud.
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  10. Reasoning with fake-skeptic Dale tends to be an exercise in futility, but what the heck, this will only take a minute:

    That this year set every record is of course important, but it misses the forest for the trees. Look at any graph of extent or volume going back as long as records have been kept, and you see a clear and drastic downward trend. Debating whether 2012 would've been the record in the absence of the storm, or "only" the 2nd or 3rd lowest, really obfuscates the issue.
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  11. Kevin C @8
    There's really no need to go elsewhere, just looking at the graphs in the article leads one to what I would say would be a fairly accurate estimate. With rate of melt similar to 2007, and being so close to the 2007 levels up to the storm, it's not unreasonable to estimate that minimum ice extent would be around the 2007 mark (specially considering no conducive weather for faster melt was recorded, except the storm).

    Thus for the purposes of this article, with the storm ice melt was 750,000 km^2 more than it should've been. Note here: NASA said they estimated from satellite photos that around 500,000 km^2 of ice was churned and broken up by the storm.

    Sorry, but I have to disagree with the comment in the article the storm wasn't responsible for the large margin. The other conditions are basically irrelevant, because if those other conditions were the cause of the large margin, then you need to justify that the melt would still have been as it was with the storm.
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  12. BWTrainer @10
    What's with the insult? Is that the only way you can argue?

    I'm not disagreeing with the downward trend, or the fact that this year would or would not have set a new record. What I disagree with is the assertion in the article that the storm is not responsible for such a large margin.

    Conditions being ripe for this occur is irrelevant. If a road develops more and more potholes each year and then suddenly one day it rains and there's a major multi-car accident, what caused the accident? The rain of course, not the potholes.
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  13. Dale - "If the storm had not have occurred, would we still have had that minimum ice extent?" (emphasis added)

    If conditions were different, we would certainly have a different minima - that should go without saying, quite frankly. I believe this falls into the category of a rhetorical question, ie. one asked for the purpose of rhetoric.

    Follow the trends, look at (as others suggested) predictions prior to the storm. It would likely have been around the 2007 minimum, which I'll note occurred with "perfect storm" of variations towards a minima. That's because the trend is downward, the central expectation is dropping severely.

    If 2007 did not have all the various factors pushing for low ice, we would have expected about 9mk^2 extent as a minima that year. If we had the same factors in play this year as in 2007, all pushing for low ice (as an "all things equal" comparison), this years minima would of course have been considerably lower than it was.
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  14. Dale@11:
    I disagree. While the 750,000km^2 number can be derived from very simple analysis, it ignores all the other information we have about the system.
    Estimating from 2007, while useful for providing an upper bound, ignores the Cryosat2, PIOMAS and ice age data, all of which indicate that the ice was thinner than 2007. While a naive analysis says a new record was likely, a less naive analysis will give a stronger result.
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  15. Dale:

    Your analogy does not hold up insofar as you are attempting to ascribe a single causal factor (rainfall) to a phenomenon (a multi-vehicle collision) which necessarily has many contributing causes (weather, baseline road conditions, driver behaviour, conditions of the vehicles involved, and perhaps others).

    For your analogy to hold, it would have to be the case that previous Arctic summer storms had caused unusual sea ice losses despite comparatively stable ice conditions.

    The OP notes two pertinent points which I think you have failed to overcome in your attempt to name the August storm in the Arctic as the primary causal agent of the record low:


    In the past, Arctic summer storms similar to the 2012 event did not have a major impact on sea ice extent or September sea ice minimum.
    [Emphasis mine.]

    The 2012 record-breaking minimum can be attributed to a number of factors. The summer storm likely played a role, but [the record-breaking minimum occured] primarily because the ice was thinner, weaker, and less extensive to begin with than in prior years due to its long-term human-caused decline. [Emphasis mine.]


    These statements from the concluding remarks are backed up with reference to evidence in the body of the OP, whereas your contrary speculation is not. The two items emphasized, taken together, quite clearly refute your attempted argument by analogy.

    BWTrainer's criticism appears to me to be more on the mark than not.
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  16. Dale,

    Go ahead and "believe" what you want to believe. It's what you'll do no matter what.

    Readers are asked to consider that the vacuous nature of Dale's (and other deniers') argument is going to become painfully clear in coming years as the Arctic ice continues to retreat, with or without such storms.

    And if such storms become more common because of changes in weather patterns that result directly from the retreat of the ice, what then?

    Obfuscation and distraction is the denier style. There's always someone else or something else to blame. There's always another reason to doubt and hesitate. There's always a reason to shirk action and responsibility.

    And there's always, always a carefully constructed reason "why," phrased as a seemingly detached, rational question, one that on the surface may seem perfectly reasonable, like "If the storm had not have occurred, would we still have had that minimum ice extent?"

    It's a question that so cleverly avoids all of the important facts, like that without warming temperatures the storm was irrelevant, or that storms like that have happened before without the same effect, or -- and this is the most important -- that the exact minimum is irrelevant, so whether or not the storm added an X factor is not relevant.

    The ice is melting. The globe is warming. This is made painfully and unavoidably obvious by each new summer minimum extent.

    Harping on nonsense like "the storm did it" is just a good way for people (like Dale) to be able to stick their heads in the ground and act like ostriches.

    A child could see through this one. Really, it's an embarrassment to deniers everywhere that they are getting this stupid with their arguments.
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  17. Dale is grasping at straws so thin that only one hell bent on shielding himself from reality would reach for them. So what if the storm made it a bigger melt? It was still far from the perfect melting conditions of 07.

    NSIDC was already predicting a new record before the storm. Perhaps it wouldn't have been shattered weeks ahead of schedule but just broken around the normal time of time of the minimum. Big freakin' difference.

    Arctic sea ice is still on a death spiral beyond any nightmarish scenario imagined by any specialist only 20 years ago. Dream on Dale, reality will catch you, whether you like it or not.
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  18. It's quite easy to convince oneself that 2012 was unremarkable. Fit a 2nd order polynomial (the highest statistically significant order) and look at the residuals. You'll find it well inside the variability of the last decades.
    (Dashed lines represent plus or minus 1σ and 2σ)

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  19. Readers,

    Dale said:
    I'm not disagreeing with the downward trend, or the fact that this year would or would not have set a new record. What I disagree with is the assertion in the article that the storm is not responsible for such a large margin.


    Which translates as:
    I'm not disagreeing with the downward trend, or the fact that this year would or would not have set a new record. What I disagree with is the assertion in the article that the storm is not responsible for such a large margin that people should pay any attention to that, when they can instead focus on particular details that confuse the issue and distract them from the fact that the Arctic is melting at an alarming rate and there's going to be hell to pay as a result.
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  20. rugbyguy59, ain't that the truth. Climategate rather convincingly confirmed the proposition that the target audience isn't willing to lift a finger to fact-check. The general situation with climate science communication in mass media strongly suggests that there are no consequences for lying outright. I'm all for limiting the possibility of mis-quoting or recontextualizing, but . . .

    But this is off-topic. The extraordinary feature of 2012 wasn't the August storm. It was the fact that long before August, area (CT SIA, not extent, which is a more consistent but much less meaningful measure) recorded 14 consecutive days of a 60-day total drop over 6 million km2. That means that for fourteen days, the average daily drop for the preceding 60 days was over 100k km2. Only one such day had occurred in the instrumental record prior (in 1985). Until yesterday, area was on a record anomaly streak of 109 consecutive days. 2012 now holds 137 daily anomaly records. 2007 is second with 69. Regardless of the storm, 2012's massive instrumental record record loss of 11,474 million km2 of area (which beat the previous record by over 534k km2) marks it as a milestone melt season.
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    Moderator Response: [Sph: Requested correction applied.]
  21. Thanks for the comments. It is odd that some people are having trouble joining the dots when it was all laid out very clearly in the main post. That fake skeptics would try and use the storm as a scapegoat to deal with their cognitive dissonance was predicted by Gareth Renowden on 12 August 2012, not to mention in the introduction to this very post, yet here they are still trying. Gareth said:

    "It will be claimed that it was all caused by the major Arctic storm that hit in August, and thus can’t be attributed to global warming."

    This blog post clearly demonstrates that ordinarily(i.e., before anthropogenic global warming initiated this paradigm shift in the Arctic system unseen for millennia) such a storm would have been a non-issue. But, because the ice is so thin, so emaciated, as a result of the rapid warming over the Arctic (most of which is because of anthropogenic warming), this storm did play a role. However, we cannot magically go back in time and remove the storm and then watch how things would have unfolded thereafter. What we do know is that even before the storm struck, the ice was in trouble, despite unfavourable conditions for ice loss. So to ask what would have happened if it were not for the storm is a rhetorical question and as such cannot be answered.

    To ask that is just looking for excuses as was predicted fake skeptics would do.

    And lest we try and fool ourselves into thinking that it is "only" the Arctic ice that is in trouble. Greenland experienced a record melt season this past summer, and that was before the melt season was even over:


    Caption: Standardized melting index (SMI) for the period 1979 - 2012. [T]he years between 1979 and 2011 use the full length season (May through September) where 2012 uses only the available period May through August 8th. Note that 2012 value is much higher than any of the previous years, despite the shorter period. [Source]

    Also, the June snow cover over the N. Hemisphere (when the albedo feedback would be greatest) continued its steep downward trend in 2012.


    [Source]

    Now putting this all together presents a very coherent and troubling picture. So perhaps it is understandable that some people are in denial.....
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  22. It's obviously impossible to answer the question 'would there have been a record minimum if not for the storm?'. My guess is that yes, there would have been, because prior to the storm the sea ice was already declining at roughly the same rate as in 2007, and the ice is thinner than it was 5 years ago. Plus I find it hard to believe that one storm could make a three quarters of a million km difference in the ultimate minimum extent.

    But as I said, there's no way of knowing, and as Albatross said, the only reason the storm made a significant difference was because the ice was already in such poor shape due to the long-term AGW trend.
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  23. Of course, the ultimate silliness will occur when a big storm arrives when there is no sea ice in September:

    "Storm prevents sea ice from recovering! If looked at in just the right way, using a 14th order polynomial extrapolation, we can see that extent was set to expand to 30 million km2 by early October! The alarmists keep saying that the planet is warming, but it's really just these pesky storms. What idiots!"
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  24. Sph@16, this all brings to mind a thought process I've had brewing, for a bit: We need to creater a new taxon, and taxonomic terminology, to these threads.

    I'll start the ball rolling: I'm sure the brain trust will polish it better.

    "Ostrichus climata minimus."

    On topic; yea, you, and all the other prevaricatin', gravy-train-entrained, conspiratorial, and lyin' *scientists* seem to agree. We did it. It's getting worse. It's not likely to get better anytime soon.

    I've long ago reached my "Oh, shit!" moment: this years Arctic news just bumps that button harder. Next year is going to be *verrrrry* interesting.
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  25. Bratisla @ 9 asked about providing a graph of rate of sea ice loss. I did so in late August/early September, in this comment on a post by Neven.

    The graph shows changes in sea ice extent from the JAXA data, smoothed with a 5-day running mean. Here is the graph again:

    Image and video hosting by TinyPic

    The August storm is the precipitous loss around day 220. Note that there was also a huge loss around day 160 - roughly two months before the storm. Generally, the loss rates are on the low side of "normal". Clearly, the August storm did affect loss rates, but clearly other factors were in play, too - much of the season prior to the storm shows loss rates as low as or lower than most previous years. Note that 2007 also had a similar minimum (greatest loss) around day 185 - so the August 2012 storm was not unprecedented in causing huge losses.

    I've kept watching the data in this manner - the rest of the season has nothing remarkable, so I won't try to post another version of the graph with the updated data. Readers that wish to do so can find links to the data at Neven's blog (or retype the url given on the graph).

    To use a baseball analogy, the melt and conditions earlier in the season loaded the bases - the storm was the clean-up batter that hit the Grand Slam home run. After that, the defence crumbled and the batting team just kept getting run after run after run. Although the one pitch that was hit out of the park was significant, you can't blame the blowout on that single factor.

    The fake skeptic's claims that everything is normal, other than the August storm, is just bunkum.
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  26. Clarification: when I say "the loss rates are on the low side of normal" and "as low as or lower than most previous years" in the above comment, I'm writing from a mathematical perspective where more negative numbers are lower on the graph. As the graph uses positive numbers for gains and negative numbers for losses, lower points on the graph actually represent a greater loss rate - so much of this season shows loss rates that exceed past years. The 2007 record was destined to be history long before the August 2012 storm.
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  27. It's worth keeping in mind that climate is defined on the basis of 20 to 30 year running averages, and cannot be interpreted on the basis of individual events, other than in the statistical likelihood of individual events occurring. The high rate of climate change in recent years challenges this definition, as statistically significant changes in climate can be discerned on a substantially shorter time frame. Moreover, these long-term changes cannot be explained by anything other than anthropogenic drivers.

    Discussion about the impact of an individual storm events on Arctic sea ice extent is relevant only in this context. It is the running average that is relevant, as clearly depicted in the topmost graph.

    Based on this trend, we can expect new record minima to be set every few years. Every time a new minimum is set, it will be due to some special circumstances that cause that individual data point to fall below the generalized trend.

    The question raised by Dale @5 is valid, but is fundamentally irrelevant in the context of climate change. If Dale's question is being raised with the intent of casting doubt upon the conclusion that AGW is responsible for the general trend, then it is a Red Herring, and should be identified as such.
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  28. Dana@4, your point is dead-on, and, whilst *doing my duty*, and reading up on the latest claptrap at WUWT, a certain moderator there, going by the intials of R.(ichard)C.(ourtney), proves beyond ~any~ doubt that there's little, if anything that can be done to stop the deniers yapping their fallacies...

    "There is no evidence of man-made global warming from emissions of fossil fuels; none, zilch, nada."

    Reality--and science, both of which move forward--will end their lunatic fantasies; well, some will. Others, as we sail past 4-5-?? degrees of warming, and food insecurity becomes a planetary catastrophe, will defend to their *deaths* that "CAGW" was just a hoax.

    Some days, it's difficult for me to focus on the science.....
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  29. The analogy I used over at Tamino's blog last month was this: The Arctic ice is like a house with a termite infestation. If a storm blows in and takes down half the house you can't really blame it on the storm. All the storm did is hasten the collapse. The real damage being done is still the result of the termite damage.

    Horatio Algeranon then graced us with this piece...

    “Thermites”

    A thermite mound
    Is at the poles
    The sea-ice found
    Is full of holes

    Weakened by
    The warming mites
    On summer days
    And summer nights
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  30. @23 DSL, Oh hell, I can actually picture that now.
    "If the seas weren't so rough the long-term ice recovery would have started this year"

    @28 vroomie, ain't that the truth? While I can't say I grace the boards of WUWT often, attempting to remedy the dissemination of misinformation on the comment boards of any given CBC article which can be tied to global warming seems like a part-time job. On every article I see the same tried and tired myths
    "the climate has changed before"
    "the warming stopped in 98"
    "it defies thermodynamics"
    "Lindzen, Spencer & Roy said"
    "climategate proved"
    et cetera ad infinitum

    This new Met office myth is proving frustratingly popular at present
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  31. I'm NOT denying that the ice melted fast, that it would've been a bad year, that the ice was thin, or that extra warmth in the Arctic has no affect.

    I'm sceptical of the claim in the article that the storm is NOT responsible for "such a large margin". Isn't that what this site is supposed to be about? Being sceptical? Well sorry, but to me you all seen "accepting" not "sceptical".

    If you want to say the storm is not responsible, you have to show that under conditions without the storm the result would have been similar.

    In this regard I don't believe you can. Yes, it's reasonable to say a new record may have been made, but not to "such a large margin". IE: if the storm had not have occurred, the record may only have been by 250,000, not 750,000 km^2.

    GET IT?

    Or are you all so willing to jump to conclusions and ASSUME things about me?

    And Sphaerica, can you please stop with the personal insults. It shows more about your character than your argument. I did not insult you, so why do you feel the need to personally insult me?
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  32. Dale: let's see how far your "skepticism" goes. You say:

    I'm sceptical of the claim in the article that the storm is NOT responsible for "such a large margin".

    If we want to make the storm "not happen", we have to replace the storm with some other weather. Let's think about what would happen if we didn't have this summer's weather, and instead had weather similar to 2007, which (nearly?) everyone agrees was ideal for arctic ice melt. In that case, I expect that my hypothetical summer of 2012 would have seen even greater melt than actually occurred. In that scenario, I would be equally justified in saying "the weather of 2012, even with its great storm of August, prevented an even greater loss of ice and a larger margin of record".

    You are playing the fool's errand of assuming that removing the August storm means that the weather that replaced it is automatically benign - that whatever weather happens instead wouldn't cause the same high rate of ice loss. Yet the graph I posted in comment #25 shows rapid ice loss around day 160 in 2012, and rapid ice loss around day 180 in 2007, and day 200 in 2009 (to name but a few). What weather events caused those rapid ice losses? What if those types of weather events replaced the August 2012 storm?

    You are falling prey to the "uncertainty" argument that fake skeptics often use: treating the situation as if every uncertainty falls in the direction of the pre-conceived conclusion you don't want to let go of. If you want to play the "what if this didn't happen?" game, then you have to specify what you think will happen in its place. Otherwise, as has been pointed out, you are just using rhetoric.
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  33. Dale... You make a valid comment. It's an unfortunate fact, however, that ideologically-motivated AGW Denialism has tainted valid skepticism. There tends to be a knee-jerk response within the scientific community to regard even valid skepticism with suspicion.

    I think the point made by several of those who have responded to your comment is that the storm was likely a necessary component of this year's melting, but that it does not provide a sufficient explanation. The other essential element is the background climate change. In other words, this year's record is highly unlikely to have occurred unless both conditions were satisfied: 1) exceptionally thin ice (due to AGW) and 2) a strong storm. (The storm itself was NOT so unusual.)

    Skeptics vary according to the level of "proof" they require before rejecting whatever is the null hypothesis. And you certainly have the right to set the bar very high, if that is your inclination. The risk you have to recognize, however, is not to lapse into dogmatism and the "Moving Goalpost" fallacy, which is common in AGW Denialism. This is partly why you've received the response that you have.

    When legitimate, unbiased climate scientists encounter what they perceive (correctly or incorrectly) as a "moving goalpost", the common conclusion is that there will NEVER be sufficient proof to satisfy them. I believe this is the actually the case for many prominent pseudo-skeptics. What's up with that?
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  34. Dale:

    The problem is that your speculatory question is directly rebutted by evidence noted in the OP. One might say it has been pre-bunked.

    dana shows several previous years in the satellite record with similar major early-August storms, and no discernable effect upon eventual sea ice extent minima. In some years, the minimum extents are higher than previously and in others they are lower. If it were truly the case that the storm was a critical causal factor in this years' minimum, surely the other years would show consistent decreases.

    In addition, your claim ignores the vulnerability of the severely-deteriorated sea ice (as a result of ongoing warming) to storm activity, which I have already quoted from the OP's concluding remarks. The effects of the storm require, of necessity, the prior vulnerability of the sea ice to have had a significant impact on the eventual minimum.

    As far as I am concerned, that is as good as saying "the storm is not responsible".

    I might also add that your behaviour here, which has been characterized as 'fake skepticism' is consistent with many of your myriad other posts on this site. No one need assume anything about you when we can review your posting history, and it strikes me as unreasonable to expect us to ignore that history when commenting on this thread.
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  35. Bob @32
    I think "replacing" the storm with 2007 weather is not valid. We know from reports that expect for the storm, the 2012 summer was pretty ordinary, not conducive for high melt like 2007, and not conducive for slow melt. Therefore "under normal conditions" replacing the storm with 2012 style of weather is more appropriate. Which under those conditions, I can see how a new record would be set, but not to such a large margin.

    CoalGeologist @33
    Fair points, and I agree. Moving goalposts are bad. But what we're talking about in this article is attribution, ie: how much ice melt did the storm or underlying conditions cause?

    We can all agree based on the long term trend that Arctic ice is shrinking due to more warmth in the region. We can all agree based on the long term trend that 2012 is an abnormality. But what caused the abnormality? Was it the underlying long term trend or natural variance?

    For that we look back at how other similar examples are done, ie precedents. If we look at long term temperature, the growth in temperature is attributed to the long term slow rising trend. Abnormalities (ie: higher or lower years by large margins) are attributed to natural variance (ie: El Nino,, volcanism, etc).

    Thus using the same principles, the underlying long term Arctic melt is attributable to the growing warmth in the Arctic. The 2012 abnormality is not. So what can you attribute such a large margin to?

    The storm.
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  36. That is a hypothesis. Dana presents an alternative hypothesis.

    The distinction between the two hypotheses is that Dana examined previous Arctic storms in order to test his hypothesis.
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  37. Dale @35:

    ...and we see that your "skepticism" is totally one-sided.

    Replacing the 2012 weather with the 2007 weather is just as valid as your choice of replacing the storm with other weather from the summer 2012 - they are both mind games. You have absolutely no justification is assuming that "no storm" means "replaced with normal conditions". Why? Because that "normal conditions" of the rest of the summer of 2012 was exactly the type of conditions that created the storm of early August. The storm is the result of a combination of dynamics and energy transfers. If the storm hadn't happened, the pressures and energy build-up would had to be dissipated in some other fashion, and the rest of the weather on either side of the storm would also not be the same. And you have absolutely no idea what that different weather would have done to the ice. You can't just erase the physics of the storm and pretend that it would not have any other effect on the physics of the rest of the season.

    In effect, you have assumed your conclusion: you are convinced that "no storm" means less of a record, because you start from a position where "no storm" can only lead to weather that causes less ice loss. You are keeping the weather that leads you where you want to go, and magically erasing the weather that might lead you elsewhere. It's cherry-picking the weather that you want. It's not science.

    ...and you haven't said a thing about the graph I presented above, that shows that large parts of the melt 2012 season had ice loss rates that were on the greater side of "normal". All it would take for the 2012 record to reach the same magnitude - in the absence of the early August storm - would be for the melt rates on some of the "low melt" days to approach the melt on some of the "intermediate" days. And physics requires that to prevent the August storm, something else would have had to change in the weather around it.
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  38. Just as a technical note, Albatross is co-author on this post and did a lot of the important research. A lot of people are saying "Dana" - I want to make sure he gets credit for his work on this too.

    I think it's accurate to say that 2012 wouldn't have broken the record by as much if not for the storm. Just like we can say 2007 wouldn't have broken the record by as much if weather conditions hadn't been ideal.

    But the point remains that similar storms in previous years had very little impact on the eventual minimum; therefore, it's safe to say that this year's storm only could have had a significan influence on the minimum because the ice was already much weaker. So if you're blaming the storm, you're also blaming the long-term sea ice decline.
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  39. Dale, I've done a back of envelope to approximate the storm damage. I used SIA, though, because I think extent is a nearly useless measure (less error prone, but also much less useful). I cam up with a max additional drop of 150,000 km2 over the remainder of the melt season. There's a clear rebound in both area and volume records that suggests that the effect is actually much less than even that.

    I'd like to know how you'd calculate it, if you had access to all data.
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  40. Dale: "The 2012 abnormality is not."

    Wrong. As I pointed out upstream, area in 2012 recorded daily anomaly record lows for 109 consecutive days -- starting in late June. Before that streak began, there was another stretch of 16 days. 2012 was dropping faster than any other year well before August. Storm schmorm.
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  41. Dale, you are leaving a factor out of your hypothetical question: that the storm itself, or at least its size, severity and duration, may be a result of the increasing warmth in the Arctic and the amount of open water present immediately prior to the storm.

    Both the climate of the Arctic and the physical nature of the sea ice has clearly changed, which means even random natural weather events, such as the storm, reflect that change at least in part.
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  42. My own inclination is to believe that the storm this summer only acted to reveal exactly how weak the remaining ice is, rather than the other way around.

    In this Dr David Barber lecture he discusses his trip on the ice breaker Amundsen where they found the quality of the ice to be substantially degraded in ways that were not being picked up by satellite imaging.

    I believe the Arctic ice sheet is about to start a final rapid decline. I may be wrong but I don't think there will be a recovery next year. I think it's slipped of the edge of the cliff and it's just a matter of how quickly it's going to hit bottom.
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  43. Bob @37
    A comment on your graph: it shows the red line moving up and down in the range of years. There's some bad melt days, and some not so bad. That looks fairly common across all years. I'm not doing the sums to see if the average daily melt is worse than the average of all other days, but I would not say it's abnormal. If it were, then the red line would stay on the high melt level all year.
    As for choosing 2007 weather conditions to replace the storm, that's cherry-picking. You're cherry-picking conditions from a bad weather year to slot into an average weather year. Comparison should be done with similar weather, not extreme weather. Like I can't say definitely that if the storm had not have occurred the weather would have been the same as it had been, you cannot say definitely the weather would be like 2007. The difference is, at least my replacement with weather conditions from 2012 is reasonable.

    DSL @39/40
    NASA estimated from satellite pictures the extent of storm damage to be around 500,000 km^2. They noted large chunks of ice broken off the main pack and pushed southwards towards warmer waters where they would melt much faster.

    Jim @41
    You forget that the article lists other storms of similar size and intensity right from the beginning of the satellite era, and no conclusion of increasing frequency or intensity of storms over time can be made.
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  44. the 2012 summer was pretty ordinary, not conducive for high melt like 2007, and not conducive for slow melt

    I think that's wrong. In the weeks preceding the storm weather conditions were very conducive for slow melt. The same conditions slowed the melt in 2010 and 2011, but they didn't this time. Just read the intros of the ASI updates on the Arctic Sea Ice blog for a chronology, especially this one.

    The 2012 melting season was the melting season that definitely confirmed that the ice is thin. PIOMAS was already telling us that for quite some time, but that's a model so we couldn't be sure. Sea ice behaviour at the end of the 2011 melting season already raised the veil a bit, but what happened this season is very strong evidence, backed up by satellite observations (CryoSat-2 and SMOS).

    Would the margin between this year's record and that from 2007 (perfect storm) be as big if the ice hadn't been as thin? That's the question.

    The pertinent question relating to the big summer storm is this: Will we see more big summer storms as the thin ice retreats earlier so that the waters warm up more?

    Let's hope not.

    Very good post by the way, Albatross and Dana. Thanks for digging up all that info on previous storms. I will re-post on the ASI blog.
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  45. Dale:

    Do you understand the link between the graph I have provided and the graphs that are in the main post by Dana and Albatross? Specifically, their figure 2? My graph is simple the slope of their graph, which means that their graph is the integral of mine - or sums, if you prefer. You don't have to do the sums to compare the average melt rates: that's in figure 2, which clearly shows that 2012 was in substantial decline compared to previous years long before the August storm. The steep slope in figure 2 is not the result of the storm, as was pointed out in the post. You are utterly wrong in using your eyecrometer on my graph to conclude that 2012 was is not abnormal in terms of ice loss.

    Yes, picking 2007 weather is a cherry pick, just as picking "normal" to replace the August 2012 storm is a cherry pick. You don't feel I'm justified in my cherry pick, yet you still haven't justified yours. If the "comparison should be done with similar weather", then you can't remove the storm and replace it with dissimilar weather ("normal"), either. Once again, you are one-sided: you are only willing to consider cases where your hypothetical "different weather" is limited to "weather that reduces ice loss". You are still assuming your conclusion.

    Your replacement of the storm with weather conditions from 2012 is not reasonable, because if the storm were somehow magically prevented then the rest of the summer's weather would not have been the same. The energy and dynamics would have to go through a significant shift in the period following the storm/not storm, to compensate for the changes in energy that "removing" the storm would have. You can't tell if the rest of the summer would have had more, less, or the same amount of ice loss without a lot more detailed analysis than your hand-waving. You need to include an analysis of everything else that would have changed after the time of the storm, presuming that the storm didn't happen.

    Unfortunately, your mind-set won't let that happen, probably because to consider that would force you to reconsider your conclusion. You will only consider possibilities that move one way: to reinforce your preconceptions.
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  46. "NASA estimated from satellite pictures the extent of storm damage to be around 500,000 km^2. They noted large chunks of ice broken off the main pack and pushed southwards towards warmer waters where they would melt much faster."

    And what exactly made the ice so susceptible to be broken off and carried away?
    Your questgion is still a rethorical one, of no real interest.

    Here is another question of that kind: NASA said 500.000 sq.km eh? If that storm would have happened at the same time of the year to the ice pack of 15 years ago, how many sq. km would have been carried away?

    What that storm reveals is not that one can quibble over a weather event to argue about how badly a record low was broken (although it did that too). It reveals that summer Arctic sea ice shows signs of being moribund. No rethoric can diminish that fact.
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  47. I just want to point out, that only Dana @38 has attempted to answer my question. Thank you Dana.

    Q. If the storm had not have occurred, would the minimum ice extent have been the same?

    A. I think it's accurate to say that 2012 wouldn't have broken the record by as much if not for the storm.

    THUS:
    The statement in the article that the Arctic storm was NOT responsible for "such a large margin" isn't entirely right.

    Regardless of all other factors, which are conditions on the long term trend, the 2012 minimum ice extent is so bad because an Arctic cyclone ripped up a huge section of ice, pushed it into warmer waters and caused it to melt a lot earlier than it would have (thus impacting other factors in the Arctic such as albedo, ice structure stability, etc etc). It is not unreasonable to propose that the Arctic storm was the cause of "such a large margin".
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  48. 46 post to try and clear the air, then the 47th post did a reasonable job of synopsis only to turn and throw another log on the fire of rhetorical excess by anchoring to the idea of storm=cause of large margin; not partial cause or marginal cause but rather "the" cause.

    A few good analogies have been used, here is mine.
    A cold and fat homeless guy meets a girl, ask for a kiss, she says no.
    Next day same guy sees the same girl only this time he has shaved, again she says no. Next day he asks again only this time he is wearing a clean shirt, same answer. This goes on for so long that finally he has warmed up, lost weight and is now dressed to the nines, he is funny with wonderfully engaging banter, he has an expensive haircut, nice watch, is very polite and respectful, only this time he has splashed on some Stetson. She has been won over and now gives him the kiss. Proportionally speaking, how much credit goes to the cologne?
    It appears that some want to assign an undue amount of credit to a storm that undoubtedly played a role in this seasons numbers but only after enormous ground work had been laid.
    I am interested in the question someone raised that posited, maybe the storm was as powerful as it was due to the extensive ice loss; ice loss driving the storm more than storm driving the ice loss.
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  49. I missed something from 47#

    The storm was characterized as "an Arctic cyclone" yet reading the article I see no mention of this label.
    Also it appears that little credit (other than where the article talks about fetch and wave action) is given by Dale to the strongest action responsible for the break up. surface waves. It is only because of the loss of ice that this fetch is created and it is only over a large fetch that wave and swell activity can reach a potential to break apart thinner sections of ice. The storms potential only exist because of the open water after the extensive loss of ice. It's not the wind on the ice, it's the wind on the water that creates a sea surface that will impact the ice.
    Wind driven ice is proportionally small when compared to the winds effect on sea surface and those effects on the ice mass

    If a mod wants to consolidate this into my post @48...?
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  50. Dale @47 - the part of the post which you are nitpicking says
    "Can this single storm really be responsible for breaking the previous Arctic sea ice record by such a large margin? The short answer is no."
    That is correct. By itself the Arctic storm was not responsible for 760,000 km2 of sea ice loss. The storm certainly played a role, but for all the reasons we discussed, the storm is not responsible for breaking the previous record.
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