NSIDC’s Walt Meier responds on the sensor issue

Dr. Walt Meier

Dr. Walt Meier

I assume that everyone has seen the post on our website discussing the changes that NSIDC has instituted to make our sea ice data available again. I don’t want to repeat that, but I thought I would respond to some of the more general issues that came up in Anthony’s posts and accompanying comments. I thank Anthony for giving me this opportunity. I write here from my personal viewpoint and not in an official capacity as a representative of NSIDC or the University of Colorado.

I apologize for the error in our data and for the relative slowness in responding to it. I’m glad that so many people are interested in the data and I understand that seeing errors is frustrating and can undermine confidence in the data. Anthony is correct that many people do now pay close attention to our website and we do have a responsibility to attend to errors as fast as we can. We will try to do better in the future. There are two major points that I hope everyone can take away from this event:

(1)  The error in no changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.

(2)  Errors like the one that occurred are part of the normal course of dealing with satellite data. We hope that they are rare, but they are not unexpected.

On the first point, there is no doubt; it is verified by numerous independent observations and is well-discussed in numerous places, including in the entries on our analysis web page.

On the second point, I think it is worth providing some background on satellite data and how it is processed, stored, and used by scientists, including those at NSIDC. In doing so, I’m not making excuses for the error in NSIDC’s data, but I hope I can help people understand how such errors are part of the scientific process of quality controlling and fine-tuning data and techniques to ultimately provide the best information possible to track climate change.

Climate science is focused on understanding long-term changes and the mechanisms that drive them. In terms of satellite data, this means taking great care and making the data as good as it can possibly be. The focus is on assuring a time series good enough to track potentially subtle trends. This involves careful quality control of data and developing and fine-tuning algorithms to convert raw satellite data into a useful climate parameter (such as sea ice extent). Like all of science this has traditionally been done slowly, methodically, and privately. And up until about ten years ago, there was no other choice but to move slowly because of severe constraints on computer processing speeds, limited data storage capacities, and difficulties in simply sharing data. One of the earliest papers to note the long-term decline in Arctic sea ice was published in 1999 (Parkinson et al., J. Geophysical Research); it was based on data only through 1996. It simply took that long to collect and carefully analyze the data, make sure algorithms were robust and stable, and get a paper through scientific peer-review.

Data distribution was also limited because of similar computational, storage, and distribution constraints. For example, NSIDC used to received updates every five years or so of final quality-controlled sea ice products. We would then distribute the data by mail on CD-ROM only to registered users.

Immediate data analysis was solely the province of operational centers, like the National Weather Service, who had special access to near-real-time data. Their focus was on getting only what was needed of any data before moving on to the next analysis or forecast cycle. Quality control was focused on catching major errors; smaller errors that didn’t significantly impact a short-term analysis were not caught or were ignored. There was no consideration given to the long-term context of the data, which were often not even saved.

There was a very clear delineation between science and operations.

Science is still done slowly and methodically, with final results disseminated the way they always have been – through peer-reviewed scientific journals. It still takes time to do final quality control on climate products. NSIDC now receives final sea ice data about once a year. But in the past ten years or so, access to data has changed dramatically. Computer processing power and data storage capacities have increased exponentially and high-speed internet has allowed near instantaneous distribution of data to a broad community. Satellite data that used to require days or weeks of processing and required dozens of tapes or CDs to store can now be processed in minutes, stored on a portable hard drive or even a memory stick, and distributed over the internet. This has been a boon to scientists who now have much faster and easier access to large amounts of data.

At the same time algorithms have matured and become more stable. This means that significant adjustments to the algorithms are not regularly needed and they can be run confidently on near-real-time data, with the understanding that the results may change during final quality-control. This has allowed to NSIDC implement a near-real-time version of the sea ice data. For the past several years this data has been freely distributed online for anyone who wished to use it, though the primary audience was scientists who would be familiar with associated caveats of using near-real-time data.

In this context, let me now move on to NSIDC and its Arctic Sea Ice News and Analysis web site. NSIDC is a science institution. Our mission is science and science support, not operational support for any kind of critical operational decisions (e.g., what regions are free enough of sea ice to be safely navigated). Because we must focus on science, the resources we can devote to near-real-time data production and analysis are limited. Nonetheless, as climate change became an important topic, it was clear that Arctic sea ice was a leading indicator of the observed changes. Since NSIDC stores and distributes the sea ice data, many people started to come to NSIDC scientists to ask about sea ice conditions and the implications for the climate. When 2005 set a record low summer extent, there was a lot of media attention; in response we issued a press release. Through summer 2006 we received many requests asking about how the ice was looking, both from the media and fellow scientists. As the summer wore on it started to feel a bit like being on a family road trip and having the kids in the back continually asking “are we there yet?” As summer 2007 started, it was a clear that a new record low was quite possible. The questions began again in earnest.

In the sense that science ultimately serves society, it was becoming apparent that scientists and the public were coming to expect a near-real-time analysis of Arctic sea ice conditions. In response, we decided to develop the website so that we could post occasional data updates and science-based discussion of the conditions. This worked quite well, but the summer of 2007 was so remarkable and Arctic sea ice had become such a big story both scientifically and in the public consciousness that we realized there would be the expectation to do even more during 2008. In response, in addition to our occasional summer posts of data and analysis, we decided to provide daily data updates and at least monthly analyses throughout the year. This decision was possible only because the products are mature and stable and further quality control to produce final data results in only minor changes. This was an added burden on NSIDC resources, but with automated processing the day-to-day impacts could be managed.

This all evolved in an ad hoc manner, with improvements made when we had resources available. Remember, none of this is NSIDC’s primary mission, which is to archive hundreds of cryospheric datasets and support peer-reviewed research. The sea ice analysis website is one of dozens of research and data management projects at NSIDC. People working on the web site often have to fit it in where and when they can amid other duties. There is no single person at NSIDC who works only or even primarily on the sea ice analysis page. This is not an ideal situation, but it is the only way we can support the analysis while still fulfilling all of our responsibilities.

This is one reason why we appeared slow to address the error last week. We have a group at NSIDC whose responsibility is to respond to user questions and comments on any of our hundreds of datasets. NSIDC’s standard is to provide a response to user inquiries within 24 hours during the business week. This is very quick for a science institution and NSIDC’s user services works very hard to always meet that standard. However, it is not particularly fast compared an operational center that works on a 24/7 schedule. We will work to put into place better QC measures and more streamlined procedures to catch future errors more quickly, but we simply do not have the resources to work in an operational environment.

This of course begs the question: why don’t operational centers do this instead of NSIDC? Operational centers do indeed provide near-real-time sea ice data. However, I believe there are a couple reasons why operational centers are not poised to provide the kind of science-based support found at NSIDC.  First, their only priority is on supporting critical users with the most useful operational information about sea ice – e.g., ships sailing in and near ice-infested waters; their data is not well-suited for easy understanding by a general audience. Second, operational centers are focused on near-real-time support, not on climate issues. Thus their expertise in putting near-real-time data in the context of long-term climate is limited.

NSIDC and other climate data/research centers (e.g., NASA GISS) do have that expertise. And that is crucial. It is only through evaluation of the near-real-time data in the context of the long-term climate that one can properly assess the relevance to climate change. This mixture of climate science and near-real-time data analysis is perhaps not optimal, but I think it is worthwhile.

The easy access to climate data has been a boon for scientists and I would argue it has also been a great benefit for society. Science ultimately serves society and quick and easy access to data provides quality up-to-date information on important issues, such as climate change. The problem is that such data can come to be viewed by journalists and other members of the public as completely routine and reliable. When small changes or errors occur, they may be given greater import than they deserve in terms of what they imply about climate change. This means there is a responsibility for places like NSIDC distributing data to thoroughly explain the data and respond quickly to any issues. I believe NSIDC does an excellent job in explaining the data through considerable documentation on all aspects of the sea ice data. However, in terms of responding to data issues, NSIDC and like centers have been slow to realize that the audience for such data has expanded beyond fellow scientists and informed journalists and that any issues need to be addressed as soon as possible lest they confuse or mislead the public. This is a difficult task for places like NSIDC, whose resources are limited and whose primary mission is not operational support. The recent data error has been a learning experience for those of us at NSIDC and we will try to do better.

I hope that this information gives people a greater appreciation for the hard-work done by my colleagues at NSIDC and an understanding of the difficulties inherent in supporting near-real-time data with limited resources amid myriad other responsibilities. Finally, I hope that people come away with a better sense of what goes into analyzing satellite data and how such data is so beneficial to our understanding of climate. Thank you.

Walt Meier

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174 Responses to NSIDC’s Walt Meier responds on the sensor issue

  1. wattsupwiththat says:

    Thank you Dr. Meier for your essay and for your open dialog. It is a breath of fresh air compared to some other researchers.

    Readers should note that over the past year, we have worked to develop a rapport with Dr. Walt Meier at NSIDC, who three times now on WUWT submitted thoughtful responses to some of our favorite Arctic questions.

    I’d like to ask you Dr. Meier, about George Will’s recent column, which has been attacked by press, bloggers, pundits, and politicians like John Kerry who recently opined that George Will’s statement below is wrong.

    Since September, however, the increase in sea ice has been the fastest change, either up or down, since 1979, when satellite record-keeping began. According to the University of Illinois’ Arctic Climate Research Center, global sea ice levels now equal those of 1979.

    Dr. Meier is George Will correct? And if not how far off the mark was he? Thank you for your consideration, Anthony Watts

    PS. In an email to me Dr. Meier suggested to me that I should check out Andy Revkin’s writeup on it. I’m sharing the link he passed on to me for my WUWT readers:

    http://dotearth.blogs.nytimes.com/2009/02/27/expers-big-flaw-in-wills-ice-assertions/

  2. Allen63 says:

    An excellent and informative response.

    Personally, I had no issue with the recent data error. But, I do agree that, in today’s environment, errors such as that one can cause trouble. Even worse, are errors that are not so obviously errors. But, your response gives me cause to believe your establishment will do its best to provide accurate information — something I had no real cause to doubt.

  3. Fernando says:

    Dr. Walt Meier:
    F13 X F15
    I have the impression that it was a simple exchange.
    Sorry I did not understand.

  4. Ed Fix says:

    Dr. Meier–

    Thank you for taking the time to write this article. I think we all are grateful for the hard work you and your colleagues do in gathering, analyzing and making this data available, and we do understand that stuff happens sometimes. With an undertaking this big, it’s a credit to you that these things don’t happen much more often.

    I really think Anthony’s first blog post wasn’t a “these guys screwed up” kind of post; it was a “Hey, there’s something here that needs attention”.

    Thanks for all your hard work.

  5. Manfred says:

    “(1) The error in no changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent IS declining significantly and the ice IS thinning.”

    i would say “has been”.

    (Hadley Center: “Indeed, the record-breaking losses in the past couple of years could easily be due to natural fluctuations in the weather, with summer sea ice increasing again over the next few years.”)

    (NASA about summer 2007: “Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic”)

  6. Jeff Id says:

    Thanks Dr. Meier, your efforts are appreciated. I hope the NSIDC will not take criticisms too close to heart and stop providing the real time service you do.

    I have processed your gridded data myself both daily and monthly, I consider the statement of “The ice extent is declining significantly” to be a bit strong. I’ve seen the loss and it isn’t much, however it is only my opinion. Your site stated,

    “By mid-February, the difference had grown to 500,000 square kilometers (193,000 square miles), which is outside of expected error. However, that amount represents less than 4% of Arctic sea ice extent at this time of year.”

    I found this to be fairly humorous as the total global sea ice ‘AREA’ decline over 30 years is only about 4% by data I downloaded from NSIDC.

    Either way, please don’t take my comments too harshly because they aren’t meant to be. Your group has a high degree of professionalism and I wish it existed more often in climatology.

    I wonder if you could answer a question, I saw in January 03, 2009 data the Hudson bay area – pre correction showed partial ice fill in some cells (<100%). I had the opportunity to overfly the bay only two weeks prior and the ice was completely packed as far as I could see. There was quite clearly 100% coverage.

    Was this an artifact of the sensors, or am I missing something?

  7. Terry says:

    Dr Meier, thanks for the information; I don’t think there is any need on your part to apologize for a sensor going bad, and really do appreciate the hard work done by your organization. If you have a minute, a few observations/questions about the writeup on NSIDC:

    However, that amount represents less than 4% of Arctic sea ice extent at this time of year.

    I know that this is a 2009 delta, but isn’t 4% about the same amount that this years extent is below the 1979-2000 average? I don’t think (or know if, or care, really) that you wrote the 2/26 update, but it seems a bit conflicting for the NSIDC to be pooh-pooh’ing a 4% sat sensor area, when at the same time emphasizing a 4% decline from average. Just one of those things that raises eyebrows, I guess.

    Also – it seems that (and please correct me on total area of potential cap) that the areas considered ice vs. land in the cryosphere have shrunk over the last 10 years. Not a lot, but enough to induce “decreased arctic ice cap” – this is totally based on eyeballing maps of ice cover on my part – it would be interesting to see (for the several regions/seas tracked, and especially those in northern Russia and Hudson Bay) the total area extent available, by year, for seas completely bounded by land and other seas tracked. The rivers seem to be shrinking in width, and some shorelines seem to have advanced into the sea. Again, that is just based on eyeballing, and I haven’t done my due diligence to get the data and plot it – one of those things that stays on the list but never seems to get done.

    Again, thanks for all of your work and information on this issue.

  8. Robert Coté says:

    (1) The error in no [way] changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.

    I am not comfortable with this statement. If the data (good or bad) doesn’t affect the conclusions, what does?

  9. Steven Goddard says:

    Below is George Will’s response to the Andy Revkin blog which Dr. Meier referred to. We really could benefit from a professional opinion, as George Will points out many problems in the Revkin response. Andy Revkin is a journalist like George Will – not an Arctic expert like Dr. Meier.

    http://www.washingtonpost.com/wp-dyn/content/article/2009/02/26/AR2009022602906.html

    Climate Science in A Tornado
    By George F. Will
    Friday, February 27, 2009; Page A17

    Few phenomena generate as much heat as disputes about current orthodoxies concerning global warming. This column recently reported and commented on some developments pertinent to the debate about whether global warming is occurring and what can and should be done. That column, which expressed skepticism about some emphatic proclamations by the alarmed, took a stroll down memory lane, through the debris of 1970s predictions about the near certainty of calamitous global cooling.

    Concerning those predictions, the New York Times was — as it is today in a contrary crusade — a megaphone for the alarmed, as when (May 21, 1975) it reported that “a major cooling of the climate” was “widely considered inevitable” because it was “well established” that the Northern Hemisphere’s climate “has been getting cooler since about 1950.” Now the Times, a trumpet that never sounds retreat in today’s war against warming, has afforded this column an opportunity to revisit another facet of this subject — meretricious journalism in the service of dubious certitudes.

    On Wednesday, the Times carried a “news analysis” — a story in the paper’s news section, but one that was not just reporting news — accusing Al Gore and this columnist of inaccuracies. Gore can speak for himself. So can this columnist.

    Reporter Andrew Revkin’s story was headlined: “In Debate on Climate Change, Exaggeration Is a Common Pitfall.” Regarding exaggeration, the Times knows whereof it speaks, especially when it revisits, if it ever does, its reporting on the global cooling scare of the 1970s, and its reporting and editorializing — sometimes a distinction without a difference — concerning today’s climate controversies.

    Which returns us to Revkin. In a story ostensibly about journalism, he simply asserts — how does he know this? — that the last decade, which passed without warming, was just “a pause in warming.” His attempt to contact this writer was an e-mail sent at 5:47 p.m., a few hours before the Times began printing his story, which was not so time-sensitive — it concerned controversies already many days running — that it had to appear the next day. But Revkin reported that “experts said” this columnist’s intervention in the climate debate was “riddled with” inaccuracies. Revkin’s supposed experts might exist and might have expertise but they do not have names that Revkin wished to divulge.

    As for the anonymous scientists’ unspecified claims about the column’s supposedly myriad inaccuracies: The column contained many factual assertions but only one has been challenged. The challenge is mistaken.

    Citing data from the University of Illinois’ Arctic Climate Research Center, as interpreted on Jan. 1 by Daily Tech, a technology and science news blog, the column said that since September “the increase in sea ice has been the fastest change, either up or down, since 1979, when satellite record-keeping began.” According to the center, global sea ice levels at the end of 2008 were “near or slightly lower than” those of 1979. The center generally does not make its statistics available, but in a Jan. 12 statement the center confirmed that global sea ice levels were within a difference of less than 3 percent of the 1980 level.

    So the column accurately reported what the center had reported. But on Feb. 15, the Sunday the column appeared, the center, then receiving many e-mail inquiries, issued a statement saying “we do not know where George Will is getting his information.” The answer was: From the center, via Daily Tech. Consult the center’s Web site where, on Jan. 12, the center posted the confirmation of the data that this column subsequently reported accurately.

    The scientists at the Illinois center offer their statistics with responsible caveats germane to margins of error in measurements and precise seasonal comparisons of year-on-year estimates of global sea ice. Nowadays, however, scientists often find themselves enveloped in furies triggered by any expression of skepticism about the global warming consensus (which will prevail until a diametrically different consensus comes along; see the 1970s) in the media-environmental complex. Concerning which:

    On Feb. 18 the U.S. National Snow and Ice Data Center reported that from early January until the middle of this month, a defective performance by satellite monitors that measure sea ice caused an underestimation of the extent of Arctic sea ice by 193,000 square miles, which is approximately the size of California. The Times (“All the news that’s fit to print”), which as of this writing had not printed that story, should unleash Revkin and his unnamed experts.

  10. Jim G says:

    Thanks for the post Dr. Meier.

    It should also be noted too that the Monday on which this occured was a US holiday.

  11. John Egan says:

    Thanks, Dr. Meier!
    It is always refreshing to deal with someone who in the academic field who actually want to convey information to a wider public rather than play chief high priest and obscure it. Your straight-forward approach is much appreciated.

  12. Gerald Machnee says:

    Steven Goddard (15:31:13) :
    George will quotes Revkin:
    Which returns us to Revkin. In a story ostensibly about journalism, he simply asserts — how does he know this? — that the last decade, which passed without warming, was just “a pause in warming.”
    *************
    So does that mean that warming is just “a pause in cooling”?

  13. Mitchel44 says:

    Thanks for the update Dr Meier,

    From your page

    “Before acquiring data from F15, NSIDC obtained sea ice data from the SSM/I sensors on the DMSP F8, F11, and F13 satellites. In March 2008, we switched from the F13 satellite to the F15 satellite because the F13 SSM/I sensor had started to have regular areas of missing data. The missing data were caused by malfunctioning data recorders on the satellite, not because of any problem with the sensor itself. At the time, we were concerned that the recorder problem would become more serious. However, the F13 data recorders have not degraded further.”

    Could you explain how the malfunctioning data recorder problem has been overcome? And if this problem persists, could you explain the adjustment/work around?

  14. Robert Wood says:

    Walt Meier should be awarded some kind of WUWT gold star for at least addressing criticism. Good for him. Smart.

    It is also a hymn of praise to the internet, although he doesn’t say as much. But, he realises that now, with the data being made instantly public, there are a thousand-fold number of data quality checkers available than his budget will allow.

    Anyhoo, Walt Meier, hat off to you sir!

  15. Mike Bryant says:

    Thanks for the update.The use of NSIDC data by CT in an obviously biased way has not been addressed. Also, I do not believe that “death spiral” is in any way whatsoever a scientific description of the state of sea ice. George Will was obviously relying on the presented data.
    Mike Bryant

  16. Gary DeBois says:

    I find it nonsensical that the debate concerning ice area extent is continuing. Is there not a dataset from 1979 that can be compared to a dataset from 2009 to determine the ice area coverage at two points in time? There must be definitive data or photographs somewhere, that both sides agree are correct, that can resolve this issue.

  17. joelseph says:

    I am very glad Dr. Meier responded. With so few willing to step into the fire and debate these days, it is certainly refreshing.

    That being said, I hope the good Dr. is not so set in his opinion that he does not entertain the idea that his conclusions may be wrong. That his data may be suspect. That perhaps he looks like he is towing a party line, or an agenda line.

    I would feel alot better if Dr. Meier had a disclaimer something along the lines of:

    “While the data our organization has collected seems to point in this direction, we certainly do not want to say the science is settled. There is much more research to be done, and definitive statements do more harm than good.”

  18. Gary P says:

    Dr. Meir, Thank you for your response.
    I do have a question about your comment #1. You state that the arctic ice is thinning. I just spent a little time searching for a link on ice thickness but I cannot find anything that is current. Are there current measurements available?

  19. Walt Meier says:

    Thanks Anthony posting my response.

    In regards to George Will, I appreciate your inclusion of the link to Revkin’s
    response. I think he does a good job of explaining the issues in a clear
    way, so I don’t have much to add. Basically, Mr. Will made three mistakes:

    1. He was factually incorrect on the date that he reported his “daily
    global ice” number. However, he was merely out-of-date with his facts
    (it was true on Jan 1, but wasn’t 6 weeks later). This is somewhat
    nit-picky, though it illuminates how fast things can change in a
    relatively short period of time, meaning that one should be very
    cautious about drawing any conclusions about climate from an isolated event.

    2. Related to that, it is easy to cherry-pick one date here and one date
    there to compare to support most any view. The important thing is to
    look at things in the context of long-term changes. That is what NSIDC
    always tries to convey by comparing to long-term averages.

    3. “Global sea ice” simply has no meaning in terms of climate change.
    The Arctic and Antarctic are unique and separated environments that
    respond differently. It would be like taking a drought in Georgia and
    torrential rain in Maine, adding those up and claiming that “rainfall is
    normal” in the eastern U.S.

    On the initial comments to this post, I’m glad that people appear to be understanding. I doubt I’ll have time to respond further to specific issues that come up in the comments, but I do see that NSIDC’s “only 4% too low “description has drawn some questions, so let me address that briefly.

    The reason to point out the 4% number is that that is within what we might’ve expected from reasonable year-to-year variability. In hindsight, it was quite obvious that data was in error, but initially, while the numbers were low, they weren’t unrealistic.

    This points out the important distinction between looking only at single data points vs. long-term trends. +/-4% at any given time is not particularly a big deal. On the other hand, January sea ice has declined at a rate of 3.1 % per decade, or roughly 10% overall since 1979. This is significant. Similarly, September ice cover has declined at a rate of over 11 % decade, or more than 30% overall since 1979.

    Now, September 2007 did get a lot of attention as a single data point because it was so far off anything expected. As some have pointed out, a “perfect storm” of conditions contributed to this event, e.g., strong winds, clear skies, warm temperatures – all things attributable to short-term weather, not necessarily long-term climate trends. However, similar conditions have occurred in the past, but did not lead such a dramatic reduction in the ice extent. So why did they in 2007? It was because the long-term decline in the Arctic sea ice – extent, and particularly thickness – made the ice cover more vulnerable to extreme weather events.

    I hope this helps further clarify a couple of issues. I’m sorry again that I probably won’t be able to respond to any other specific comments or questions.

    Thank you.

    Walt Meier
    NSIDC

  20. Mike Bryant says:

    “I apologize for the error in our data and for the relative slowness in responding to it.” -Good.

    “We will try to do better in the future.” -Hmmm.

    “The ice extent is declining significantly and the ice is thinning.” -Data?

    “The focus is on assuring a time series good enough to track potentially subtle trends.”-Is it “good enough”? That seems like a very low bar.

    Did we ever learn if this is really a voluntary effort?

  21. Robin Flockton says:

    How about talking to people who live in Arctic Canada/N. Shore Alaska. I think they are experiencinging something entirely different to the satellite information described.

  22. Juraj V. says:

    “The ice extent is declining significantly”
    - shouldn´t be better to use term “minimum summer ice area is declining significantly”? Ice -is- declining significantly every spring-summer and growing every autumn-winter. Sometimes I think people imagine that the icecap is one big steady ice cake which is getting a bit smaller every year. We know how it is, but not sure with ordinary news readers. Otherwise thanks from Europe for interesting insights.

  23. Steven Goddard says:

    Walt,

    Thanks for your response.

    From a quick eyeballing of the UIUC graph, it appears that global sea ice area has been well within one standard deviation of the mean for all of 2009, not just on January 1. This would be considered normal. So I would say that George Will was correct about global sea ice.
    http://en.wikipedia.org/wiki/Normal_distribution
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg

    It also appears clear that Arctic ice area did make it’s greatest recovery in the satellite record during last winter, as George Will mentioned.
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.area.jpg

    In my view , on all counts George Will was correct. He did not discuss long term trends, and regardless I am not convinced that 30 years is a long enough record to determine if the trend is linear or cyclical. I suspect not. We do know that ships made it closer to the pole in open water 70 years ago, than Lewis Pugh made it last summer.

  24. jae says:

    A toast to Dr. Meier! And a bet of 1,000 quatloos that she doesn’t thaw as much this summer.

  25. Walt Meier says:

    OK, just one more, because Gary P brings up a good point about thinning of the ice cover.

    Complete data is very hard to come by. Ice thickness is a very difficult thing to measurements. However, from submarine sonar measurements, ground measurements, more recent satellite measurements (since 2003), it is pretty clear that ice has been thinning quite substantially for a long time and the thinning has accelerated. One of the easier ways to at least get a sense of ice thickness is to look at ice age, which is much easier to track. First-year ice, ice that has formed since the end of the previous melt season, can only grow to about 1-1.5 m (3-5 feet) during the winter. Multiyear ice, ice that has survived at least one summer melt season and can continue to grow in subsequent winters, can get much thicker, up to 3-4 m (10-15 feet) thick or even more. Older multiyear ice is on the high end of that scale, while younger multiyear ice is closer to first-year ice values.

    It is quite clear that there is much less multiyear ice than there used to be. We’ve discussed this from time to time on NSIDC’s news and analysis site, for example:

    http://nsidc.org/arcticseaicenews/2008/040708.html

  26. thefordprefect says:

    Mitchel44 (15:47:42) you could read the whole of the page:

    Correcting the daily time series
    The daily extent map now shows any areas of missing data as dark gray regions, speckles, or spider web patterns. However, in the time series chart we account for the missing data by averaging the extent for that region from the day before and the day after the gap, a mathematical technique called interpolation.

  27. TerryBixler says:

    Walt Meier
    Thank you for your direct commentary here. It is appreciated by all.

  28. Steven Goddard says:

    Walt,

    It would seem that the amount of multi-year ice can increase substantially in just one year of low polar drift. Do you expect that the amount of multi-year ice at the end of this winter will be greater than it was at the end of last winter?

  29. james griffin says:

    As the satellite pictures show an increase in ice coverage how can Walter Meier state it is declining when it is coming back.

  30. TonyB says:

    Anthony

    In the context of this thread can I suggest it might be worth making periodic references to Pen Hadow-my relatively near neigbour who is trekking to the post towing a radar device behind him to record the thickness of the ice.

    As far as I can see that will merely record the thickness a few feet wide in a straight line from starting point to the north pole and wont touch the other 99.9% of ice not measured, but it is a serious and dangerous expedition that probably deserves a write up.

    TonyB

  31. Fernando says:

    The Rev. I apologize.
    I am happy.
    ….”Ice thickness is a very difficult thing to measurements”.
    3…..[ “Global sea ice” simply has no meaning in terms of climate change.
    The Arctic and Antarctic are unique and separated environments that
    respond differently...]….
    Well:
    there are years of misinformation.
    today you do a good service to science
    Maybe: I be dumb enough.
    Thanks Dr Meier

  32. paulhan says:

    Can anyone help me on this. I appreciate it is not specific (but is related) to this posting.
    I see all sort of claims as to how much sea levels will rise if the ice melts, but they seem way over the top to me.
    It seems there is about 1.8% of water locked up in ice on Greenland and Antartica, and that the average depth of the ocean is 1km. To me that would imply that if it all melted, sea levels would rise by 18 metres, and not the 60-100 metres I regularly see quoted about the media.
    Further, the coastline of every country is not a cliff, it rises gradually from sea level, so as the sea rises it would have to cover a much greater area. Also, at the temperatures that would be required for this to occur, surely a lot of it would end up as water vapour. Would that not imply that sea level rises would be closer to say, 10 metres.
    Lastly, are we really saying that all ice is going to melt, given that temperatures in those places are -50 degrees C. Even if the temperatures rose by 5C generally, and even say 10C at the poles, that would still leave it -40C. It has to be 0-1C to melt. On Mars, where there is nearly 100% CO2 in the atmosphere, and much hotter temperatures, there is still ice just under the ground at the poles.
    This strikes me as one of the more egregious claims of GW alarmists, and yet I do not see it questioned much.
    paulhan.

  33. Thanks to Dr. Meier on the second point, That was the information I wanted to have.

    On point one I do find strange the position that he needs to defend conclusions of NSIDC in regards to Arctic Ice extent trends. I do not think anyone seriously was saying that the rate of decline over the long term (as short of time period it actually represent geologically speaking) was affected by this instrument error. Has someone called into question their current assessments and calculation of the trend?

    I think all here would agree the frustration in “long term trends” as a point of debate on sea ice is that we have no way of knowing if the trend is unusual, we have only one short time period to judge. Yet If I take the monthly chart, I can not help but make note of the reversal in extent loss as a point of interest to watch and learn what is influencing it, I do not look and say hey there is more ice extent, better put out a statement over and over and that it is meaningless.

    Will it become a long term trend, will it stop, reverse? Only time will tell.

  34. I’d just like to thank Dr. Meier for his response and for his open and detailed answers to further questions. Much appreciated, Dr. Meier!

  35. Philip_B says:

    The error in no changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.

    With respect, Dr Meier is merely reiterating what is little more than dogma.

    The facts are that,

    1. Summer Arctic sea ice extent has declined significantly in the last few years.

    2. Winter Arctic sea ice extent has declined by far less.

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

    3. This means that if ‘record’ ice melt has occured then there must have been similarly ‘record’ ice freezing in order for the winter ice level to be maintained.

    4. The ‘ice is thinning’ argument is mostly inference based on the melt of ‘old’ perennial ice and its replacement by new annual ice. If more ‘thinner’ new ice were indeed a factor in increasing ice melt we would see less new ice. In fact, last year (the latest data I have) we saw an increase in the new ice as Dr Meier himself reports.

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

    Further, on new ice replacing old ice; It’s likely this is a natural cycle of old ice being replaced every few years by new ice. If this weren’t true, we would see large areas of very old ice, which we don’t see (ie the old ice doesn’t exist). Hence old ice melts on a regular basis/cycle and is replaced by ‘thinner’ new ice. So it is likely the proportion of new ice and the thickness of new ice has no relevance to long(er) term sea ice trends.

    More generally, this appears to be another example of natural variability being extrapolated out into the future and claimed as evidence of AGW.

  36. Squidly says:

    Robert Coté (15:28:43) :

    (1) The error in no [way] changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.

    I am not comfortable with this statement. If the data (good or bad) doesn’t affect the conclusions, what does?

    What does?: Politics and Agenda

    I must apologize to Dr. Meier, although I respect his posting here and acknowledgment, I find that by immediately citing to point (1) has discredited his means and motivation in my mind. It sounds way too much to me like “whoops, sorry about the sensor, but we still believe the ice is all going to melt and we’re all going to die” crap. I fully well respect the hard work (I too work very hard), the level of expertise that may be within NSIDC (I too have expertise), but the direction of the personal inferences imposed by this leaves me more unconformable than I was before. Perhaps I am just better at reading between the lines than most.

    I am sorry, this just doesn’t get a passing grade from me.

    Respectfully,
    ..

  37. a jones says:

    Whether you might cavil at some of the comments he makes Dr. Meier is to be congratulated on being forthright and open. Unlike many of his supposedly more important peers.

    And to be fair to NSIDC they make their data freely available. Unlike some publicly funded researchers.

    Now there is quite a lot I could say about the way NSIDC present some of their conclusions, analysis and so forth: so I am not going to.

    I am merely going to remind you that the Arctic Ocean is effectually a largely enclosed sea subject to enormous variations from wind, current and so forth. To read anything into the variation in Arctic sea ice and extent from day to day or year to year or even decade to decade is an exercise in fatuity.

    No matter we all do it, like the gambler obsessed with the next roll of the dice or the deal of the cards, like the stockmarket speculator who imagines examining the prices from day to day will lead to fortune.

    I confess I do it myself, it’s like talking about the weather. By Jove have you seen yesterday’s drop in temperature on this, that or the other satellite data. What do you think it means?

    Nothing at all of course: unless it’s caused by a nearby supernova or suchlike. In which case we will all know about it and in pretty short order.

    Antarctica is a continent surrounded by sea and with a stable wind pattern. Things there probably happen very slowly: and anyway we have very little data about it.

    By contrast things in the Arctic happen with great speed, it changes year on year, and from historical data going back some two hundred and fifty years we can suppose that the Arctic regions have been gradually warming for at least this length of time; but we don’t know by how much or whether this is a long term trend and linear or part of a cycle, or indeed anything else. Except to say that it is a bit warmer than it was back then.

    So thank you Dr. Meier and this board but can I go back to sleep now?

    Kindest Regards

  38. WestHoustonGeo says:

    While I appreciate how hard they work over there at NSIDC , I also work in data acquisition and processing.

    On January 22, 2009 a poster on WUWT noted an overnight disappearance of a huge chunk of icw off Labrador. I regret I did not note his userid, but I have a screen capture of the comparison. (That’s significant because Cryosphere Today has “dissappeared” 2009 from their website.)

    I take it that nobody over at NSIDC (or Cryosphere) actually looks at plot from today and that from yesterday and asks themselves “Does this make sense?”

    As a man who has been held responsible for data quality for many years, I find that puzzling – nay, disturbing.

  39. Steven Goddard says:

    According to IPY (International Polar Year) ice is melting at both poles “faster than expected.” Given that global sea ice is normal, it would appear that they must not have been expecting very much melt, or that they are lacking in basic information which they could pick up easily from the UIUC web site.

    It also appears that not everyone necessarily agrees that the behaviour of the two poles is unrelated. An IPY official predicted that the Arctic might be ice free last summer.

    Polar icecaps melting faster than expected

    Wednesday 25 February 2009
    The International Polar Year survey, a vast enterprise involving thousands of scientists, has revealed that icecaps around the Poles are melting at a faster rate than expected.

    http://www.france24.com/en/20090225-icecaps-around-north-south-poles-melting-faster-expected-scientists-international-polar-year-survey

  40. Bill Illis says:

    Thanks for the answer Walt.

    It helps to understand your perspective.

    I still think it would be helpful to make the daily sea ice extent and daily sea ice area numbers available to the general public. Even if there are corrections at a later date. Perhaps you could partner with some other data dessemination agency. I note Jaxa has been updating the daily sea ice extent data in an easy-to-use CSV file although their data only goes back to 2002.

    To help out my (would like to have that is) friend George Will, after finding the NSIDC site yesterday where the monthly sea ice extent and sea ice area data which is based on the current algorithms used (and after finding all the intervening years in a text file) (and I hope I have your permission),

    I am plotting up the year-end Global sea ice extent and Global sea ice area back to 1978.

    http://img144.imageshack.us/img144/7512/seaicearea.png

    http://img216.imageshack.us/img216/7661/seaiceextenty.png

    And just to show this is the same data NSIDC uses, I have replicated the Northern Hemisphere Extent Anomaly (in % from the 1979-2000 average) that we are used to seeing with the same data.

    http://img222.imageshack.us/img222/8499/nhextent.png

    Which is the same as:

    ftp://sidads.colorado.edu/pub/DATASETS/NOAA/G02135/Dec/N_12_plot.png

    So, George Will was right after all and to echo Jeff Id, I don’t think it is really fair to use this measure when the actual NH sea ice extent is not declining that significantly. What it has done is give many people the wrong impression (they all just knew that George Will was wrong even though he was right about the point he made.)

  41. Jeff Id says:

    I didn’t think my question was too bad.

    Anyway, thanks for the article.

  42. Mike Bryant says:

    Squidly,
    I understand how you feel. The response would have been so much better if he had said,
    “We have made statements in the past that were a little “over the top”. Since I am the man heading this agency, I will make sure that I review every statement to make sure we are not promoting alarmism. The term “death spiral” was especially egregious.
    Thanks,
    Walt”

  43. Robert Wood says:

    Frankly, as a Canadian, I hope it gets warmer and there will be less ice in our attic. There will also be a longer growing season for wheat and other crops, and a smaller heatingn bill, resulting in less GHG emissions by our power plants.

  44. Squidly says:

    Steven Goddard (17:07:36) :

    Faster, hotter, accelerating, accelerating faster than before, record acceleration …

    I think it is rather ironic to hear all the time about the importance of “long term trends” for climate and especially see ice. However, on the other hand, we go from one year to the next and suddenly someone finds that things are accelerating at an alarming and record rate, never before observed. It seems that long term trends get shorter every year. Perhaps this is a natural effect and there is a correlation between acceleration and the length of the term trend?

    Still not buying it!

  45. Dave says:

    Anybody know what the global sea ice extent was during the Medieval Warm Period?

  46. MySearch4Truth says:

    There was a story on the NSIDC website entitled ‘Near-real-time data now available.’ http://nsidc.org/arcticseaicenews/

    The article was radically edited from Feb. 24th related to the DMSP F13 and DMSP F15 satellite sensors. In the last article (a copy was found at: http://www.spaceref.com/news/viewsr.html?pid=30658) it was stated that “For several years, we used the SSM/I sensor on the DMSP F13 satellite. Last year, F13 started showing large amounts of missing data. The sensor was almost 13 years old, and no longer provided complete daily data to allow us to track total daily sea ice extent. As a result, we switched to the DMSP F15 sensor for our near-real-time analysis. For more information on the switch, see “Note on satellite update and intercalibration,” in our June 3, 2008 post. ”

    The new article (edited) goes on to say, “NSIDC stopped displaying the problematic data, and recalculated sea ice extent using data from the DMSP F13 satellite, an older sensor in the same series of satellites. The recalculation changed the January monthly average ice extent by less than the margin of error for the sensor. As we reported in our February 3 post, growth of Arctic sea ice did indeed slow in January because of unusual atmospheric conditions. Using F13 data instead of F15, the September daily minimum that we reported on September 16, 2008, changed from 4.52 million square kilometers (1.74 million square miles) to 4.54 million square kilometers (1.75 million square miles), within the margin of error for daily data.”

    The old article states, “As a result, our processes underestimated total sea ice extent for the affected period. Based on comparisons with sea ice extent derived from the NASA Earth Observing System Advanced Microwave Scanning Radiometer (EOS AMSR-E) sensor, this underestimation grew from a negligible amount in early January to about 500,000 square kilometers (193,000 square miles) by mid-February ” and goes on to say, “We are actively investigating how to address the problem. Since we are not receiving good DMSP SSM/I data at the present time, we have temporarily discontinued daily updates. We will restart the data stream as soon as possible.

    Some people might ask why we don’t simply switch to the EOS AMSR-E sensor. AMSR-E is a newer and more accurate passive microwave sensor. However, we do not use AMSR-E data in our analysis because it is not consistent with our historical data. Thus, while AMSR-E gives us greater accuracy and more confidence on current sea ice conditions, it actually provides less accuracy on the long-term changes over the past thirty years. There is a balance between being as accurate as possible at any given moment and being as consistent as possible through long time periods. Our main scientific focus is on the long-term changes in Arctic sea ice. With that in mind, we have chosen to continue using the SSM/I sensor, which provides the longest record of Arctic sea ice extent. ”

    Why not just use the AMSR-E sensor which is more accurate? Instead you choose an old faulty one?

    Watts Up With That?

  47. gofer says:

    OT, but Bill McKibben in his latest WAPO article, cheering on tomorrow’s climate demonstrations, called James Hansen “Our foremost climatologist”…I thought he was an astronomer. Also learned CO2 is “drying out the trees”.

  48. Manfred says:

    @james griffin (16:39:12) :

    “As the satellite pictures show an increase in ice coverage how can Walter Meier state it is declining when it is coming back.”

    this happens all the time. you need to give in detail the time interval you are talking about and better, a reason why you selected these dates.

    Dr. Meier chose the present tense but “meant” the time from 1979 till end of 2007. this decline is in correlation with the co2 increase but also with the warm ocean currents cycle, solar activity and reduced volcanic activity.
    So, this trend doesn’t prove any agenda.

    however, long term ocean currents have changed recently and solar activity is now in a minimum. so the coming years may serve for a good estimation of the contribution of these natural cycles. long term temperature trends can be explained with these cycles and without any greenhouse gas contribution, and the coming years may show the same for arctic sea ice.

  49. Jim Cripwell says:

    What I find disturbing is that in most of the NSIDC reports, somehow it is felt it is necessary to add what is little more than the normal mantra from the supporters of AGW, that what is happening to Arctic sea ice, supports the idea that CO2 is causing global temperatures to rise. The data supplied by NSIDC is superb, and it only takes away from the excellent science that NSIDC is obviously doing, to lend support for what is little more than a hypothesis; that AGW is real.

  50. Philip_B says:

    This is the correct 2nd link, quoting Dr Meiers.

    http://www.nasa.gov/topics/earth/features/seaice_conditions_feature.html

  51. Petras says:

    All of this hindsight “confirmation” is fine, but what would be truly useful is a forecast. Given current ice conditions, if next year was “average,” what would the ice look like? If the hypothesized trend continues, what would the ice look like? If you add confidence intervals, do the two forecasts overlap? How surprising was the growth this year. Did anyone forecast the rapid growth or are we limited to post-hoc explanations (of course, there was rapid sea ice growth ….)?

  52. TerryBixler says:

    Where has the disappeared ice gone? As the sea level has not changed its rate of rise in the last 100 years at around 2.2mm / year. http://www.pol.ac.uk/ntslf/products.php Projections abound that it will accelerate to 29 or more mm / year but so far this acceleration has not been measured. So where has all those cubic miles of ice gone?

  53. Just want truth... says:

    Walt Meier,

    Thanks for the dialog. It’s rare to find congenial exchanges in this issue the past couple of years.

    The review process on the internet is stricter than the peer-review process of “scientific journals”. There’s no way out of that for you at the NSIDC. You are going to be constantly checked for accuracy, especially since JAXA data can be so easily used as a comparison.

    I do have a piece of advice : you might want to withhold on drawing conclusions on what is ‘normal’, what is ‘average’, or what should be expected for Arctic ice since the data used to create the averages, the norms, are from such a short time period. It would end all arguments if we had satellite data for the past 2000 years. Then we could have a good idea what is ‘normal’ for Arctic ice. But we only have satellite data from the last 30 years. We can’t be sure what is normal. For example, we don’t know how much ice there was at the Arctic during the Medieval Warming Period. For that matter, we don’t know for sure how much there was 50 years ago.

    I would say that when the NSIDC uses words like normal and average the phrase ‘for the last 30 years’ should always be seen with them. This may alleviate some of the criticisms.

  54. John G. Bell says:

    1979 Christmas was the year of the sweater in my family. It was the cause of much hilarity that we all hit upon the same gift, but no surprise as it was a terribly cold winter. A particularly unfortunate choice of year to start a graph on Sea Ice and more so as satellite data goes back several years earlier.

    Back then some dim bulbs thought the next ice age was knocking on our door. The problem is that we only live a few decades. That doesn’t allow us a sense of the true natural variability of climate. The last couple thousand years in North America have experienced enough climate change that if like changes were to repeat they would result again in mass human migrations.

    Natural change. Worth understanding and without a doubt real.

  55. Pink Pig says:

    I haven’t looked at the cause of this error in great detail, but I take exception to the broad claim made by Dr. Meier suggesting that satellite data is more error-prone than other forms of data. The fact is that most errors are indeed human in origin, and the more we can eliminate humans from the processing of data, the more accurate we can expect the results to be. The best data possible is recorded automatically by computers, and if it is processed without human intervention, it will generally be the most reliable of all information. Computer errors do occur, but they tend to be quite random (and therefore noticeable).

  56. Jeff L says:

    Dr. Meier & all posters :
    Thank you for a civilized discussion of this subject! Very refreshing!

    2nd, I know you measure area via satellite, but what about thickness? Is that measured by satellite or by other methods? There have been quite a few questions about this posted. I think everyone would be interested to learn more – how it is measured & what they data shows over time. Thanks!

  57. pft says:

    Ok, we can put the failed sensor to bed for now. It was really only an issue since they did not detect the error first.

    “For average absolute error, or the amount of ice that the sensor measures compared to actual ice on the ground, the error is approximately 50 thousand to 1 million square kilometers (19,300 to 386,100 square miles). ”

    http://nsidc.org/arcticseaicenews/faq.html#quality_control

    Thats up 1- 7% of the total ice being measured.

    They are not using satellites that provide more accurate data so as to have better historical comparisons. I do not understand that. They might try error bands, or just show both sets of data on the same graph, but if there is better data available, it should be used.

  58. Allan M R MacRae says:

    Thank you ladies and Gentlemen all for your gracious comments.

    I expect there was much less ice in the Arctic in the early 1940′s than today.

    We know that 1934 was the warmest year in the lower 48 states of the USA.

    We also know that 2008 was no warmer globally than 1940. See
    http://www.iberica2000.org/Es/Articulo.asp?Id=3774

    We also know the story of the good ship St. Roch:

    In 1940-1942 the St. Roch became first vessel to complete a voyage through the Northwest Passage in a west to east direction.

    In 1944, she became first vessel to make a return trip through the Northwest Passage, through the more northerly route considered the true north west passage, and also the first to navigate the passage in a single season.

    Why compare to 1979-1980? After WW2 there was ~30 years of moderate global cooling that ended in ~1977. Lots of sea ice then.

    Try comparing today to 1940-45.

    Then please recognize that humanmade CO2 emissions have increased ~800% since ~1940. And it is no warmer today than in 1940.

    Please tell me again how CO2 is driving catastrophic global warming.

    Also, since CO2 lags temperature at all measured scales, please tell me how the future drives the past.

    Regards, Allan

    *****************************************

    St. Roch
    From Wikipedia, the free encyclopedia

    Career
    Launched: 1928 at Burrard Dry Dock Shipyards
    Fate: Designated a Canadian National Historic Site at the Vancouver Maritime Museum in 1962
    General characteristics
    Displacement:
    Total Length: 37.8 m
    Length, waterline:
    Beam:
    Draft:
    Mainmast,height from deck:
    Foremast,height from deck:
    Propulsion: Sails & a 150-HP diesel engine[1]
    Sail area:
    Mainsail area:
    Crew:
    The St. Roch is a Royal Canadian Mounted Police schooner, the first ship to completely circumnavigate North America, and the second sailing vessel to complete a voyage through the Northwest Passage. (It was the first ship to complete the Northwest Passage in the direction west to east, going the same route that Amundsen on the sailing vessel Gjøa went east to west, 38 years earlier.)

    The ship often was captained by Henry Larsen.[1] The ship can now be found at the Vancouver Maritime Museum in Vancouver, British Columbia, Canada and is open to the public for scheduled visits.

    History
    1928 – constructed in North Vancouver, British Columbia, Canada at Burrard Dry Dock Shipyards
    1929-1939 – supplied and patrolled Canada’s Arctic
    1940-1942 – became first vessel to complete a voyage through the Northwest Passage in a west to east direction
    1944 – became first vessel to make a return trip through the Northwest Passage, through the more northerly route considered the true north west passage, and also the first to navigate the passage in a single season
    1944-1948 – patrolled Arctic
    1950 – became first vessel to circumnavigate North America, from Halifax, Nova Scotia to Vancouver, British Columbia, via the Panama Canal
    1954 – returned to Vancouver for preservation
    1962 – designated a Canadian National Historic Site at the Vancouver Maritime Museum

  59. Ozzie John says:

    Off topic but,

    NASA has just published the official figures for SSN, 10cm radio flux and AP progression for February. I was surprised by the prompt update considering last months effort.

    Almost no change from the Jan. data. AP progression is slightly up from the record lows, but not much…!

    AMSU data also shows a downwards trend in line with the ENSO peak several months ago.

    Anthony – I was wondering if you could explain trends in the AMSU satellite data over the past decade. There appears to be a trend to (decadal) higher ch04 temperatures at near surface level, but colder at 90mb and higher elevations. If I were a AGW activist I might conclude that this was caused by more IR absorption at lower levers leading to colder upper atmosphere

  60. Terrence says:

    I agree entirely with what Robert Coté said at (15:28:43):
    “(1) The error in no [way] changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.
    I am not comfortable with this statement. If the data (good or bad) doesn’t affect the conclusions, what does?”

    And, with what Squidly said at (16:58:37):
    “I am not comfortable with this statement. If the data (good or bad) doesn’t affect the conclusions, what does? … What does?: Politics and Agenda
    Dr. Meier … has discredited his means and motivation in my mind. It sounds way too much to me like “whoops, sorry about the sensor, but we still believe the ice is all going to melt and we’re all going to die” crap.

    Dr. Meier’s statement (1) reminds me of Mann’s laughable “hockey stick”. Apparently, you would get a “hockey stick” from random numbers, as well as any other “data” you put through the “program”. Politics and Agenda, preconceived “ideas”, disregard for data, what does it matter? I work hard and am out to save the planet (from evil mankind).

  61. Lance says:

    From a previous comment Dr. Meier posted:

    First-year ice, ice that has formed since the end of the previous melt season, can only grow to about 1-1.5 m (3-5 feet) during the winter….

    I would like to know what factors dictate this.

    I worked in Eureka NWT in ’79-80, and have a photo of myself holding the entire ice auger that I used to drill and measure the ice thinkness, I don’t recall what the exact depth was, but I’m looking at least 15-20 feet of auger….

    This was new ice that form in the Fiord from Aug to the Spring, before all the ice melted (and or pushed out to Eureka Sound)

  62. Rocket Man says:

    Mr. Meier,

    You stated that “from submarine sonar measurements, ground measurements, more recent satellite measurements (since 2003), it is pretty clear that ice has been thinning quite substantially for a long time and the thinning has accelerated.”

    How long is long? Sonar hasn’t been around a long time and it’s use to measure ice thickness has certainly been around for an even shorter amount of time. 2003 to early 2009 is not a long time. So are we left with ground measurements. How long does the data on ground measurements go back and really, how extensive are they? But realistically, I am skeptical that ground measurements can tell you anything about what is happening to the global ice sheet thickness.

    Plus, where is the data to support this assertion? I would love to see the data, including the measurement instrument used, its accuracy, location and coverage.

    I am sorry, but the exaggerated claims made by others in your profession has made me very skeptical of claims that do not reference the underlying data. Show the data and let the data speak for itself.

  63. Jim Steele says:

    Meir wrote “Global sea ice” simply has no meaning in terms of climate change.
    The Arctic and Antarctic are unique and separated environments that
    respond differently.

    I find that a bit curious. Why is the “global temperature” indicative but not “global sea ice”? A good argument can be made that heat release and absorption by the oceans make global air temperature less reliable. And since the top few meters of oceans contain more heat than the total atmosphere, Global Sea Ice may be a more accurate metric.

  64. Ron de Haan says:

    I would like to thank Dr. Walt Meier for his posting and his answers.
    With all respect for Dr. Meier and his hard work, I am convinced that we are dealing with natural cycles.
    All we see today has happened before.
    I do not think the thickness of the ice is something to worry about.
    As soon as the AGW doctrine has disappeared from the agenda, (because it has fulfilled it’s goal or because it has failed) this subject will be closed.
    I do not believe there is an antrophogenic factor at play that influences the ice melt.

    I would like to refer to an article about the subject from John Daly
    It starts with a report from the President of the Royal Society, London, to the Admiralty, 20th November, 1817
    “It will without doubt have come to your Lordship’s knowledge that a considerable change of climate, inexplicable at present to us, must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been during the last two years, greatly abated.

    (This) affords ample proof that new sources of warmth have been opened and give us leave to hope that the Arctic Seas may at this time be more accessible than they have been for centuries past, and that discoveries may now be made in them not only interesting to the advancement of science but also to the future intercourse of mankind and the commerce of distant nations.”
    President of the Royal Society, London, to the Admiralty, 20th November, 1817

    see: http://www.john-daly.com/polar/arctic.htm

    That’s it.

  65. John H says:

    (1) The error in no changed any of our conclusions about the long-term changes in Arctic sea ice.

    Well the alarmists had certainly clammed onto the news before the error was caught.
    So the mistaken ice loss contributed to forming reports on sea ice loss.

    Now that the loss is less by

    “By mid-February, the difference had grown to 500,000 square kilometers (193,000 square miles), which is outside of expected error.”

    Shouldn’t it mean something? Like say the earlier alarms of accelerated loss repealed?

    Obvioulsy this error may not change the overall conclusions that sea ice volume is fluctuating downward but we should not be allowing false reports to add severity and the corrected reports to mean nothing.

    While Dr. Meier’s states that
    “Global sea ice” simply has no meaning in terms of climate change”
    that is not the case in the political and media arenas.

    Every downward shift in sea ice is embellished and taken advantage of by the Gore/Hansen community with real time alarms sounding urgency.

    I really feel that Dr. Meier has some responsibility to attempt to establish some contraints and recognition of the true meaning of global sea ice.

    It’s not enough to quietly do so.

    And in light of the recent correction of data and apparent return of sea ice to near 79 levels Dr. Meier’s ongoing reports should not be inappropriately used as fodder by the alarmists.

  66. deadwood says:

    I have noticed that both “sides” in the AGW “debate” pick and choose data and time periods to best illustrate their points.

    As a geologist I like to pick as long a period as is possible, but that is likely a result of my own bias as well.

    Be that as it may, as a geologist I do not see the 20th century as being particularly alarming one way or the other. I see that the 20th century max temperatures and even max rates of temperature change to be unremarkable when compared with the information we have gathered for the past. This also appears to be true for ice, both in the artic and antarctic.

    Is there some kind of relationship between CO2 and temperature or with ice in arctic (or global ice)? I have yet to see any convincing evidence one way or the other.

    Do we as a nation or as a global society have enough information to make a decision regarding the use of fossil fuels? And by this I mean information more compelling than models that fail to adequately account for rather simple processes such as water vapor and ocean/atmosphere circulation. Again, the honest answer is no.

    The precautionary principle remains the strongest of all the arguments forwarded by the backers of the AGW hypothesis, but this by itself is not reason enough to destroy our economy and with it our standard of living.

    George Will’s Feb 15th column does not mention the precautionary principle, but touches on the uncertainty of the data we all must deal with. Unfortunately in taking issue with the alarmist camp and their manipulation of the data, but uses the same tactic. I think that was unfortunate and hurts his message.

    The real issue here in my opinion is whether the facts support drastic action. Models are not facts. Data, minus manipulation, are facts. To date these are not complelling.

  67. Ben Lawson says:

    Thank you for your thoughtful contribution, Dr. Meier. It lays to rest a number of poorly formed criticisms. The responses here are an informative intellectual litmus test too… Some commenters are adjusting their arguments to accommodate your information, some are “having none of it”, some are trying to put words into your mouth!

    In case you return to comment again, can you address this incidental thought: disappearing sea ice has little impact on sea level because it floats (some people here should take a moment to think about that). Continental ice/snow loss will be the change reflected in sea levels.

  68. hotrod says:

    First I would like to thank Dr. Meier for his detailed response!

    It was helpful. It does raise a few questions as well, but an open exchange of information is critical to the on going debate and as others have stated, the time and effort to make the response is much appreciated.

    Having worked in Government organizations, I would have to defend the NSIDC in the context that the “product” the public and blog communities have come to expect, is apparently outside their funded scope and I am sure is produced as significant expense in time and effort squeezed out of things they are mandated to accomplish. That good will effort is also much appreciated.

    That said, it is also apparent that the expectation of the public, at large for this data to be available on the internet in near real time, has created a legitimate justification for the NSIDC to attempt to get funding and staffing to support some useful public real time data products, from all the recently allocated funds.

    This is a classic case of “mission creep” where the public expectation has clearly created a real and useful demand for some of their data products, and it would go a long way if the product was a properly funded and supported output from already existing data products.

    It is unreasonable for the public at large, to demand a product, that they are not willing to pay for, and I for one think this product is worthy of a FTE position to support it and properly handle day to day issues.

    Thanks for your efforts, and although I share some of the reservations expressed by others above, it will serve no useful purpose to regurgitate them.

    Your open response is refreshing and much appreciated.

    Larry

  69. evanjones says:

    Thanks, Dr. Meier for an open and honest exchange. One may agree or disagree, but one appreciates a game with all cards on the table.

  70. Geo says:

    Dr. Meier is a true credit to both science and public service. He has proven yet again that he is a shining example of the axiom that is not necessary to be disagreeable while disagreeing.

    Thank you, Walt, from a taxpayer.

  71. J. Peden says:

    [snip - take that to email please]

  72. AnonyMoose says:

    Much of Meier’s article should be in “History” pages of the NSIDC web site, to educate their current and future visitors. The text has been written, they may as well continue to use it.

  73. Molon Labe says:

    Re: Jim Steele (19:45:34) . Excellent points. It bothers me that so much emphasis is placed on atmospheric temperature when we have two giant heat capacitors at each pole which transfer heat to and from the atmosphere at constant temperature.

  74. J. Peden says:

    Dr. Meier, anyone can make excuses. But why are you incapable of seeing possible errors?

  75. Ron de Haan says:

    “NSIDC’s Walt Meier responds on the sensor issue « Watts Up With That?”

    ” ..as climate change became an important topic, it was clear that Arctic sea ice was a leading indicator of the observed changes.”

    “Alarmists Walt Meier and Ted Scambos endorse Gore’s fraud”

    TED: I think An Inconvenient Truth does an excellent job of outlining the science behind global warming and the challenges society faces in the coming century because of it.

    WALT: I agree. I think Gore has the basic message right. But we thought we could clarify a few things about the information concerning snow, ice, and the poles.

    WALT: RealClimate.org, a non-profit, non-governmental site run by scientists, has a good entry on the movie. See http://www.realclimate.org/index.php?p=299.

    See: http://tomnelson.blogspot.com/

  76. P Folkens says:

    Dr. Meier contributed valuable information and insight with class — the sort of class exhibited by Anthony Watt on a regular basis. I do hope this continues as it elevates the discussion and debate to levels where improved understanding may evolve.

    My greatest concern is the definition of “long-term trend.” We must be careful in how we use it. The long-term trend that begins in the late 18th Century is clearly warmer. However, the long-term trend that begins in the 9th Century is clearly cooler. From climate maximums three or four thousand years ago the trend is cooler, not unlike previous interglacials when the latter stages of the interglacials were cooler than the early stages.

    Dave (17:34:49) wrote: Anybody know what the global sea ice extent was during the Medieval Warm Period?

    The MWP varied quite a bit (no surprise there). Recent northern Greenland anthropological studies have found ancient sea levels several meters higher than now associated with coastal habitats in areas that were frozen and iced over until recently. These discoveries are suggesting an ice-free eastern Arctic for at least part of the year with much higher sea levels within the time frame of the MWP.

  77. Peter Jones says:

    Great Lakes Ice Coverage is interesting to look at also.

    http://ice-glaces.ec.gc.ca/Ice_Can/GL/CVCSWCTGL.gif

  78. paulhan (16:49:32) :


    Lastly, are we really saying that all ice is going to melt, given that temperatures in those places are -50 degrees C. Even if the temperatures rose by 5C generally, and even say 10C at the poles, that would still leave it -40C. It has to be 0-1C to melt.

    It’s nowhere near -50C during the summer at the poles, except perhaps some places high on the antarctic ice sheet. The coastal areas usually have temperatures temperatures well above 0 during a few summer months, in the north the temperature may even get above 0 in any month as far north as 80N for that matter. While temperatures may rarely go above 0 on the top of the Greenlandic ice sheet, ice still moves, and if the ice at the coast breaks off faster, the ice of the interior will move faster towards the coast than new ice can replace it. I think that’s the basic idea.

  79. paulhan: The rule of thumb I was taught is that the ocean bottom is at about 4 km depth over most of the ocean.

    http://en.wikipedia.org/wiki/Ocean#Physical_properties has 3.7 km average depth.

    The same article claims that all fresh water constitutes “less than 3%” of the total; most of this will be in ice caps. Please redo your calculation in the light of these figures.

    One of the nicest features of science is coherence.

  80. Policyguy says:

    Mike Bryant,

    Did you ever get a response from Walt Meier about your post on 12/26/08 on a 12/24 article, pertaining to an apparent ice extent/snow extent mapping change that would have the effect of shrinking the available area for arctic sea ice?

    Mike Bryant (05:16:27) :
    Dr.Walt Meier,
    Can you please explain a couple of things on the Cryosphere Today “Compare side-by-side images of Northern Hemisphere sea ice extent” product, please?

    Why does the snow in the more recent dates cover areas that were previously sea inlets, fjords, coastal sea areas, islands and rivers? (Water areas, most easily discernible in the River Ob inley

    Why does the sea ice in the older images cover land areas? (Land areas, most easily discernible in River Ob inlet)

    See this overlay: http://i44.tinypic.com/330u63t.jpg

    Looking forward to your answer,
    Mike Bryant

    If so, or if not, where do we stand on the change being discussed over Christmas?

    Thanks

  81. a jones says:

    No we do not have any reliable records of the ice in the Arctic ocean in the MWP.

    Such accounts as we have, both Chinese and Viking, which suggest that the Arctic ocean was navigable at that time, at least in the summer. were written one to two hundred years later and must therefore be accounted as legendary.

    If so the legend of the North West Passage so affected the British psyche that they looked for it for five hundred years. Without much success.

    But we do know that according to contemporary written record, because mariners keep pilotage records, that by 1200 the outbound direct Norway Greenland route had closed in winter due to sea ice and ships had to go via Iceland and that by 1250 not only were the northern Greenland colonies being abandoned but that outbreaks of scurvy were becoming commonplace on the return voyage.

    We don’t know why other than the passage times were much longer and perhaps fresh supplies were in short supply in Greenland. By the way these are the first accounts we have of scurvy.

    Again although they could measure their latitude they had no reliable means of measuring longitude so it is hard to be sure how exact their observations were.

    You see although it is despised in an age of satellites there really is a measured and written down and contemporary record going back a thousand years.

    Kindest Regards

  82. Eric Anderson says:

    Dr. Meier, thank you for the professional tone and helpful information. Particularly useful to hear about the practical aspects of making the data available and all the work that you and your colleagues are doing. Many thanks for the efforts and your commitment to continue making this valuable resource available.

    Philp_B wrote:

    “This means that if ‘record’ ice melt has occured then there must have been similarly ‘record’ ice freezing in order for the winter ice level to be maintained.”

    Unless I am missing something, this is a very lucid point that deserves repeating.

  83. Antonio San says:

    Dr. Meier, many have found the NSIDC explanation for not using the 30 years average record normally accepted in the climatology field, quite unconvincing at best. Considering government agencies computational means, how come the NSIDC is unwilling to do change its average from 1979-2000 to 1979-2008 and recalibrate the database? It is obvious that the 1979-2000 average maintains artificially a higher average than would the accepted 30 years baseline, although as one figure pointed out on the NSIDC site by not much. Still this goes to methodoly: what makes the NSIDC decide arctic sea ice measurements should compare to a 21 year average? What’s next? Another field will prefer 15 y average perhaps? Sure it doesn’t reverse the trend but it enhances it and perhaps one day it may mask the trend’s reversal.
    Thank you for your answer.

  84. Antonio San says:

    Oh Dr. Meier if I may abuse of your time just a little more: Pr. Maslanik of Boulder said it was measured that in 1980 only 20% of the arctic sea ice was represented by multi year ice 7y old or older. Thus my question: what happened of the rest of 20y old, 50 y old, 100 y old, 200 y old sea ice then? If no 200y old sea ice existed then or now, does it not mean that periodic important melts are the nature of the beast? And thus the decline observed in arctic sea ice since the mid 1970s is concomittant with the trajectory changes of polar anticyclones in the Atlantic North (thesis of Alexis Pommier 2005 under the direction of Marcel Leroux) or in the Pacific Northeast (Favre and Gershunov 2006, 2008) and thus is linked to the well documented climatic change initiated then and whose connection with the theory of CO2 AGW is yet to be demonstrated?
    Thank you again for your time.

  85. AndyW says:

    I think this boils down to once again how the media can think they can interpret values without checking from the scientists whether the interpretations they draw are valid or not, ie see a graph or be told a percentage and then come to your own decision on what it means. Or more like what you WANT it to mean.

    So I’m glad NSIDC will be spending more time on their “operational” style data for the general public even though it is outside their remit. Maybe in part payment people like Michael Asher and George Will will actually ask them for the scientists comments rather than just misunderstanding what they see? Then everyone will be happy.

    Regards

    Andy

  86. TonyB says:

    Antonio Sam

    You make an interesting point about the age of ice. Are you able to link us to the studies? Thanks. From my own research it appears that substantial ice melt is a regular occurence so it would be good to see some actual scientific research on the subject

    TonyB

  87. Norm in the Hawkesbury says:

    Steinar Midtskogen (22:12:07) :

    It’s nowhere near -50C during the summer at the poles, except perhaps some places high on the antarctic ice sheet.

    You are correct, see this ‘real-time’ image – http://amrc.ssec.wisc.edu/~amrc/AWSMCMTA.GIF
    Parent URL = http://uwamrc.ssec.wisc.edu/realaws.html

    The synoptic charts for both the Indian and Pacific oceans see -
    http://www.bom.gov.au/cgi-bin/nmoc/latest.pl?IDCODE=IDX0033 – Indian

    http://www.bom.gov.au/cgi-bin/nmoc/latest.pl?IDCODE=IDX0032 – Pacific

    It’s closing in on the end of summer but the temps are below freezing. Is that early?

  88. Malcolm says:

    They key point for me that has not been answered is that the trend in ice data may well be part of a longer natural cycle. There is a lot of historical data that highlights that the Artic ice sea extent was of a similar magnitude 60-70 years ago as it is today.

  89. ROM says:

    Probably not strictly relevant to the present discussion but this article is on the north Greenland settlements by the Independence I Culture some 6000 to 7000 years ago.
    The Independence I Culture apparently disappeared from north Greenland some four to four and a half thousand years ago as north Greenland got colder.
    It was replaced by the Inuit Culture which was adapted to the colder temperatures.
    http://www.sciencedaily.com/releases/2008/10/081020095850.htm

  90. Mike Bryant says:

    Policyguy,
    Nope, nevergot an answer from Meier or Chapman. Apparently, Dr. Meier only cares if his data is used to promote common sense.
    Mike Bryant

  91. thefordprefect says:

    Antonio San (23:54:22) :
    … 20% of the arctic sea ice was represented by multi year ice 7y old or older. Thus my question: what happened of the rest of 20y old, 50 y old, 100 y old, 200 y old sea ice then?

    Doesn’t ice melt from below and above?

  92. Smokey says:

    Mike Bryant, I have to agree with your take on this situation.

  93. thefordprefect says:

    Peter Jones (22:05:55) :
    A long term study shows later freeze and earlier breakup trend on the majority of North American Lakes:
    http://www.cfr.washington.edu/classes.esc.401/LakeIcePhenology07.pdf

  94. Richard says:

    I live in Southwest Florida. I just stepped outside (not a scientific study, no mean averages to speak of), and I just have one thing to say about global warming: may I have some more, please?

    Richard

  95. Malcolm says:

    The link below is a paper on the Artic Sea Ice Fluctuations from1953 to 1977 by John E Walsh & Claudia M Johnson, Journal of Physical Oceanography.

    http://ams.allenpress.com/archive/1520-0485/9/3/pdf/i1520-0485-9-3-580.pdf

    One of the paper’s conclusions is that, and I quote, “The trend in total Artic Sea ice extent computed from the 300 month sample is POSITIVE and statistically SIGNIFICANT”.

    To put it another way, there was a recorded growth in the Artic Sea ice extent from 1953 to 1977.

    Now compare that SIGNIFICANT POSITIVE trend from 1953-77 to the SIGNIFICANT NEGATIVE trend computed from the satellite data since 1978 to the present, 2009.

    Two things are immediately apparent.

    The Artic Sea ice extent in the late 1970s and early 1980s was at a RECORDED HIGH.

    The longer term trend from 1953 to the present, 2009, is UNLIKELY to be significant.

  96. Pete S says:

    Thank you Dr Meier for a very informative piece. I was about to ask you to refute Gore’s sometimes very alarmist comments on the Arctic region, but then I read Ron de Haan’s last posting. I sincerely hope that your clarification regarding the poles will eventually lead the VP to modify his forecasts of catastrophic sea level rises etc.

  97. Terry Bixler (17:56:47)

    Hello Terry,
    You are about to become an expert on ice melt;
    get a glass, fill it with warm water, put a ice cube into the glass !

  98. foinavon says:

    Philip_B (16:57:06) :

    [Eric Anderson (23:13:19)]

    Philip_B wrote: 1. Summer Arctic sea ice extent has declined significantly in the last few years.

    2. Winter Arctic sea ice extent has declined by far less.

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

    3. This means that if ‘record’ ice melt has occured then there must have been similarly ‘record’ ice freezing in order for the winter ice level to be maintained.

    4. The ‘ice is thinning’ argument is mostly inference based on the melt of ‘old’ perennial ice and its replacement by new annual ice. If more ‘thinner’ new ice were indeed a factor in increasing ice melt we would see less new ice. In fact, last year (the latest data I have) we saw an increase in the new ice as Dr Meier himself reports.

    Sea ice will always form in the arctic winter and it is not surprising that the extent of the winter sea ice is receding much more slowly than the extent of summer sea ice. However the winter sea ice will be increasingly new ice, since the locales where new ice is forming on top of older sea ice (at least one season old) is receding back to ever higher latitudes. So those observations (reduced winter sea ice recession and increased areas of exclusively new ice) are pretty much what is expected in a warming arctic with a warming-induced recession of sea ice that is strongly represented in summer sea ice extent.

    The ice thinning argument is not an “inference”, although one can infer that new ice formed directly on the water surface will be thinner than ice that accumulates on pre-existing sea ice. Ice thickness is directly measured by a number of methods. Try, for example:

    K. A. Giles et al. (2008) Circumpolar thinning of Arctic sea ice following the 2007 record ice extent minimum Geophys. Res. Lett. 35, L22502

    abstract: September 2007 marked a record minimum in sea ice extent. While there have been many studies published recently describing the minimum and its causes, little is known about how the ice thickness has changed in the run up to, and following, the summer of 2007. Using satellite radar altimetry data, covering the Arctic Ocean up to 81.5o North, we show that the average winter sea ice thickness anomaly, after the melt season of 2007, was 0.26 m below the 2002/2003 to 2007/2008 average. More strikingly, the Western Arctic anomaly was 0.49 m below the six-year mean in the winter of 2007/2008. These results show no evidence of short-term preconditioning through ice thinning between 2002 and 2007 but show that, after the record minimum ice extent in 2007, the average ice thickness was reduced, particularly in the Western Arctic.

    Haas C et al. (2008) Reduced ice thickness in Arctic Transpolar Drift favors rapid ice retreat Geophys. Res. Lett. 35, L17501

    Abstract: Helicopter-borne electromagnetic sea ice thickness measurements were performed over the Transpolar Drift in late summers of 2001, 2004, and 2007, continuing ground-based measurements since 1991. These show an ongoing reduction of modal and mean ice thicknesses in the region of the North Pole of up to 53 and 44%, respectively, since 2001. A buoy derived ice age model showed that the thinning was mainly due to a regime shift from predominantly multi- and second-year ice in earlier years to first-year ice in 2007, which had modal and mean summer thicknesses of 0.9 and 1.27 m. Measurements of second-year ice which still persisted at the North Pole in April 2007 indicate a reduction of late-summer second-year modal and mean ice thicknesses since 2001 of 20 and 25% to 1.65 and 1.81 m, respectively. The regime shift to younger and thinner ice could soon result in an ice free North Pole during summer.

    Maslanik JA et al. (2007) A younger, thinner Arctic ice cover: Increased potential for rapid, extensive sea-ice loss Geophys. Res. Lett. 34, L24501

    Abstract: Satellite-derived estimates of sea-ice age and thickness are combined to produce a proxy ice thickness record for 1982 to the present. These data show that in addition to the well-documented loss of perennial ice cover as a whole, the amount of oldest and thickest ice within the remaining multiyear ice pack has declined significantly. The oldest ice types have essentially disappeared, and 58% of the multiyear ice now consists of relatively young 2-and 3-year-old ice compared to 35% in the mid-1980s. Ice coverage in summer 2007 reached a record minimum, with ice extent declining by 42% compared to conditions in the 1980s. The much-reduced extent of the oldest and thickest ice, in combination with other factors such as ice transport that assist the ice-albedo feedback by exposing more open water, help explain this large and abrupt ice loss.

  99. foinavon says:

    Antonio San (23:54:22) :

    Oh Dr. Meier if I may abuse of your time just a little more: Pr. Maslanik of Boulder said it was measured that in 1980 only 20% of the arctic sea ice was represented by multi year ice 7y old or older. Thus my question: what happened of the rest of 20y old, 50 y old, 100 y old, 200 y old sea ice then? If no 200y old sea ice existed then or now, does it not mean that periodic important melts are the nature of the beast?….

    Here’s what Maslanik et al say [***]:

    “The area where at least half of the ice fraction in March consists of ice that is at least 5 years old has decreased by 56%, from 5.83 × 106 km2 in 1985 to a minimum of 2.56 × 106 km2 in 2007. Most of the perennial pack now consists of ice that is 2 or 3 years old (58% in March 2006 vs. a minimum of 35% in March 1987). The fraction of 5+ year old ice within the MYI decreased from 31% in 1988 to 10% in 2007. Older ice types have essentially disappeared, decreasing from 21% of the ice cover in 1988 to 5% in 2007 for ice 7+ years old. The greatest change in age distribution occurred within the central Arctic Basin. In this area (region 1, Figure 1), 57% of the ice pack was 5 or more years old in 1987, with 25% of this ice at least 9 years old. By 2007 however, the coverage of ice 5+ years old decreased to 7%, and no very old ice (9 + years old) has survived. From 2004 onward, and in particular in 2006 and 2007, the remaining oldest ice has been confined to a small portion of the Arctic (regions 6–8); essentially a relict of the perennial ice cover of 20 years ago.”

    Clearly there are regions of long lived perennial ice. However these are increasingly small. The statements about the complete loss of very old ice refers specifically to the central Arctic basin.

    [***] Maslanik JA et al. (2007) A younger, thinner Arctic ice cover: Increased potential for rapid, extensive sea-ice loss Geophys. Res. Lett. 34, L24501

  100. stan says:

    I’m glad that Dr. Meier is savvy enough to understand that it is in everyone’s best interests that he avail himself of the opportunity to come on a site like this. He doesn’t have to, but it really is the wisest course of action.

    That said, I’m not very impressed with what he wrote (originally and in the responsive comments. First, given his multiple references to “peer-reviewed” science, he must be far more impressed with the peer review process than I. And I’m not very impressed with his criticism of George Will, either. Pretty weak stuff. When he typed “nit-picky” to describe his point, that should have been a red flag that he needed to do some self-editing.

    Then he wrote:
    “Global sea ice” simply has no meaning in terms of climate change. The Arctic and Antarctic are unique and separated environments that
    respond differently. It would be like taking a drought in Georgia and
    torrential rain in Maine, adding those up and claiming that “rainfall is
    normal” in the eastern U.S.

    Perhaps he thinks this clever, but it’s really not very responsive. The term “global sea ice” has a lot more meaning than the term “global termperature”. Given the context of this whole episode, this aspect of Meier’s argument is really disappointing.

    Alarmists are the ones who have raised the specter of declining ice for the purpose of claiming that the GLOBE is changing. To criticize Will for referring to the globe is completely ass-backward.

  101. DaveE says:

    “P Folkens (21:40:24) :

    These discoveries are suggesting an ice-free eastern Arctic for at least part of the year with much higher sea levels within the time frame of the MWP.”

    Interesting. Do you have a source for that?

    The implications of much higher sea levels to me is that much of the Antarctic Ice may have melted too.

    DaveE.

  102. MattN says:

    “Where has the disappeared ice gone? As the sea level has not changed its rate of rise in the last 100 years at around 2.2mm / year. http://www.pol.ac.uk/ntslf/products.php Projections abound that it will accelerate to 29 or more mm / year but so far this acceleration has not been measured. So where has all those cubic miles of ice gone?”

    Terry, Terry, Terry (shakes head)…..

    Fill a glass with ice water, mark the level, let it all melt and watch the water level NOT rise one bit.

  103. Garacka says:

    What is “long term” in the Arctic?

    The 30 year period since 1979 when, coincidentally, satellites started providing data and cooling changed to warming, or, say, 60 years to align with the Pacific Decadal Oscillation? As I understand it, the 30 years since 1979 is probably best viewed as a 1/2 cycle. This seems worthy of more public comment, if for no other reason, to make people think you’re being objective. (Sorry)

    On the Will column, it seems that he was dead on.

  104. Garacka says:

    ….that Will’s column was dead on

  105. george h. says:

    Since global temperatures have declined at the rate of approximately 0.4C per decade since 2000, ongoing thinning of Arctic ice or loss of summer ice extent is most likely due to local circumpolar factors or influences, is it not?

    If globally influenced, why is this not consistent with an ongoing rebound from the little ice age?

    Next, how is it possible to determine a climate related trend with such a short period of observation as the alarmists want to do. Accurate satellite measures of Arctic ice only began in 1979 giving us exactly two (30 year) climate data points.

    I realize Dr. Meier will not be commenting further, but I would be curious to know how he would answer these questions and what he could tell us about sea ice extent or volume during the MWP, Roman, Minoan warming periods and during the Holocene Optimum.

    Also, how much melting occurred in the period between 1910 and 1940 when temperatures increased more than they did between 1980 and 2000?

  106. Dr. Meier,
    I would like to add my voice to the others above in thanking you for your comments and information.
    I would like to ask you a question that I am sure has some merit, as your working life is the study of ice, Arctic sea ice past and future trends, have you or NSIDC done a study on historical records? there are thousands of written references going back hundreds of years on fishing, military and exploration, perhaps you know of some paper that has been written giving ‘trends’ on written information, (ROM (01;58;02) gives a reference and 4,000 years as a starting point. Any information would I am sure be appreciated by all.

  107. Shawn Whelan says:

    If so the legend of the North West Passage so affected the British psyche that they looked for it for five hundred years. Without much success.
    Actually they were successful.
    McClure and his men were the first to travel the passage in the early 1850′s.

    An Arctic Timeline : 1496-1962
    http://www.south-pole.com/arctic00.htm

  108. DR says:

    Let’s guess foinavon, the arctic sea ice conditions are “unprecedented” in human history, and irreversible due to increases in atmospheric CO2, right? That is of course unless we take drastic action, high taxes and government control, to curb the inevitable catastrophe.

    Quote all the “peer reviewed” (fast becoming an advocacy mechanism masquerading as science) articles predicting such doom, there’s no shortage of them. Much of modern day “research” is little more than workfare for otherwise unemployed scientists. The sow’s teets are swollen from the milk of public treasure.

    Since the hockey stick, Hansen’s “smoking gun”, Santer’s non-existent hot-spot, Dessler 2008 runaway water vapor feedback, Steig and countless others, many are questioning the whole process of publishing in journals as being a dumping ground for pro-AGW propaganda rather than real legitimate scientific research.

    Getting your picture on the cover of The Rolling Stone Nature does not make it legitimate in my book.

  109. Hank says:

    It’s great that Walt Meier is willing to interact on this blog. What I am curious about are the particulars of how this sensor failed. Since it seemed fail by drifting away from typical numbers it had been producing, how confident is the NSIDC that they can pinpoint exactly when this sensor began to fail and does this tell their engineers anything about accuracy of these instruments and the ways they should be calibrated?

  110. Steve Keohane says:

    Mike Bryant (04:11:38) I had wondered that myself since I posted that overlaid image in December. I have thought of making a pixel count of the delta in the shoreline, but it seems overly ambitious and tedious to do by hand. It would be much simpler if Walt would just address the difference. Glad to see the image is still kicking around.

  111. foinavon says:

    Malcolm (04:46:47) :

    The link below is a paper on the Artic Sea Ice Fluctuations from1953 to 1977 by John E Walsh & Claudia M Johnson, Journal of Physical Oceanography.

    http://ams.allenpress.com/archive/1520-0485/9/3/pdf/i1520-0485-9-3-580.pdf

    One of the paper’s conclusions is that, and I quote, “The trend in total Artic Sea ice extent computed from the 300 month sample is POSITIVE and statistically SIGNIFICANT”.

    To put it another way, there was a recorded growth in the Artic Sea ice extent from 1953 to 1977.

    John Walsh reassessed and extended his analysis of Arctic sea ice extent from observational (and including satellite data) back to 1900 (and forward to 1997) in work published in 2001[***].

    The conclusions are that considering winter (i.e. max) sea ice extent, the levels were largely flat from 1901 to around 1972 from which they progressively trended downwards; i.e. continually reduced max sea ice extent from around 1972-1997 (and beyond as we now know).

    Considering minimum (summer) sea ice extent, the values were flattish from 1901 to around 1970 (with some bumps giving minor maxima in summer sea ice extent around 1915 and 1950)….followed by a progressive decrease through to 1997 (and beyond as we now know).

    The total sea ice extent was flattish from 1901 through to 1970, followed by a progressive decrease from that time (and beyond as we now know).

    As Walsh and Chapman point out, the earlier analysis was based on spatially limited data sets, and they describe a range of new data sets that give spatial coverage throughout a greater proportion of the Arctic region and allow extension of the series back to the start of the 20th century. The data for the pre-satellite period is still lacking in full coverage, and this should still be considered provisional (I would have thought!).

    [***] Walsh JE and Chapman WL (2001) 20th-century sea-ice variations from observational data Annals of Glaciology 33 444-448

    Abstract: In order to extend diagnoses of recent sea-ice variations beyond the past few decades, a century-scale digital dataset of Arctic sea-ice coverage has been compiled. For recent decades, the compilation utilizes satellite-derived hemispheric datasets. Regional datasets based primarily on ship reports and aerial reconnaissance are the primary inputs for the earlier part of the 20th century. While the various datasets contain some discrepancies, they capture the same general variations during their period of overlap. The outstanding feature of the time series of total hemispheric ice extent is a decrease that has accelerated during the past several decades. The decrease is greatest in summer and weakest in winter, contrary to the seasonality of the greenhouse changes projected by most global climate models. The primary spatial modes of sea-ice variability, diagnosed in terms of empirical orthogonal functions, also show a strong seasonality. The first winter mode is dominated by an opposition of anomalies in the western and eastern North Atlantic, corresponding to the well-documented North Atlantic Oscillation. The primary summer mode depicts an anomaly of the same sign over nearly the entire Arctic and captures the recent trend of sea-ice coverage.

  112. Jim Powell says:

    Dr. Meier thank you very much for taking your time to make this post. I have followed the global warming issue for several years now. The best overall explanation that I have read so far is by Dr. Syun-Ichi Akasofu. http://people.iarc.uaf.edu/~sakasofu/pdf/recovery_little_ice_age.pdf
    He has a 400 year perspective of the issue.

    When I looked at the current ice situation in the arctic a definite pattern appeared. The ice in the seas closest to the North Atlantic were below normal. When making the statement “The error in no changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning”, and I am reading into this from a previous post “It is the preponderance of evidence presented in thousands of articles that provides the foundation for the human-induced global warming theory” that you feel that the declining ice is due to man caused global warming, how do you separate out the influence of the Atlantic Multidecadal Oscillation, NAO/AO? Here is a link, http://www.bnhclub.org/JimP/jp/seaice2252009.JPG
    to how I separated out the northern cryosphere. All of the seas that are in direct contact with the North Atlantic are slightly down. The Bering Sea is up by 36%. Why is it that the seas in contact with the North Atlantic are influenced by global warming and the Bering Sea is not?

    My belief is that the atmosphere is warmed by the oceans and not the other way around. The AMO and the PDO having been in the peak of there 60 year cycles and are warming the atmosphere of the northern hemisphere. Would you agree with that? Shouldn’t the focus be on a sea by sea basis? Would you please explain what the different issues that are associated with the Sea of Okhotsk sea ice? It is geographically separated from the rest of the northern cyrosphere. Thank you.

  113. TerryBixler says:

    Alan
    Got it, but then we assume that only the ice floating on the ocean has shrunk and not the ice connected to land mass. Funny how ice knows where it lives. Sorry I did not include the thought in the original post. Further some metrics suggest that the sea levels have actually declined in the latter part of the 20th century (tide gages)

  114. Garacka says:

    Anyone else getting tired of so many references to research being prefaced with “peer-reviewed”?

    Given the number of major climate topics where peer review has failed, you’d think that the climate folks should be coming up with a new term to discourage folks from looking behind that curtain.

  115. Pamela Gray says:

    Ice thins in a warm ocean. Ice thickens in a cold ocean. The Arctic currents are connected to the cold and warm phase of the Atlantic Oscillation. There are both warm and cold currents that mingle in the area, from oceanic and fresh water sources. If you know where, when, and how ice melts in the Arctic ocean, and you know where, when, and how the Arctic currents flow, ice thinning and thickening long term trends makes perfect natural sense.

  116. jlc says:

    Let’s not get carried away. Walt Meier is government employee with some science qualifications. He is not Galileo and he is not Neils Bohr.

    It appears to me that his response is part of a strategy to throw a few bones to the sceptics without conceding any ground.

    As another commenter noted, we all work very hard – this does not mean that we are always (or ever) right.

    Without definitions (particularly of “long-term”) this is neither scientific or honest.

    In addition, the numerous typos and grammatical errors do little to inspire confidence.

  117. Robert Rust says:

    Mr. Meier,

    Do you remember the 1st time you responded to Mr. Watts after he reported the incorrect information published by your organization? You said something along the lines that it didn’t make sense why Mr. Watts would blog about this.

    Mr. Meier, given that you’re right in the middle of an organization that feeds the media information that is getting a very large amount of global attention. A large amount of Global Attention. In order for me to believe the post you have put up here, I have to believe that you do not have the slightest clue regarding the perceptions of people across the planet. I read each word of your lengthy post looking for some kind of acknowledgement on your part. Here is the only sentence that I could find:

    ———————–
    Dr. Meier says…..
    However, in terms of responding to data issues, NSIDC and like centers have been slow to realize that the audience for such data has expanded beyond fellow scientists and informed journalists and that any issues need to be addressed as soon as possible lest they confuse or mislead the public.
    ———————–

    Again, you’re asking me to believe that you’re totally clueless about how the media uses information from your organization for their purposes. Even though most commenters have been able to, I do not understand why you’d get a pass for this.

  118. Grant Hodges says:

    I’m sorry. I’m not enamored with Dr. Meier’s reply. Certain things he mentioned ignore facts, to the point that I am not sure that anything could change his mind.

  119. Eric Anderson says:

    Thanks, foinavon.

    You wrote: “. . . one can infer that new ice formed directly on the water surface will be thinner than ice that accumulates on pre-existing sea ice.”

    Just a dumb question on my part:

    How does new ice accumulate on pre-existing ice? Does it grow in the water from underneath? Other than some minor amount of snowfall from above that might get compacted into ice, it seems there wouldn’t be any “thickening” from above.

  120. Jack Green says:

    Somebody needs to study the recently failed sensor history from when it was manufactured and see if it has failed in the past. How long has it been used and are there any other ways of testing if the historical data has been “questioned” because of it? Do we have independent verification of sea ice extent such as digitizing satellite photos, on the ground measurements, etc. I’m sorry if this has been already discussed but I would not trust data from a failed sensor that was not discovered for a couple of months. It means to me that the scientists have relied on it without question and have designed a system that has no backup or scaling sequence. In my work I always have independent verification built into my modeling as “reasonableness check” before I make any conclusions. Just a thought.

  121. Malcolm says:

    Just to correct a typo, (Malcolm (04:46:47)):

    I said: “The Artic Sea ice extent in the late 1970s and early 1980s was at a RECORDED HIGH. ” That should have been “late 1960s”.

    In addition:

    It is noticeable from the paper, see link below, that Artic sea ice extent was at low for the period 1957 to 1964.

    http://ams.allenpress.com/archive/1520-0485/9/3/pdf/i1520-0485-9-3-580.pdf

    This marked low in Artic Sea ice extent is very similar to the low recorded over the last 6-7 years. So you can contend that such periodic and extended lows are not uncommon. As such they should be included when determining the long term mean values for Artic Sea ice extent.

    I estimate that the mean value for Artic Sea ice extent for the period 1978 – 2000 is at least 0.5 million sq. km. higher than that of the mean value for the longer period 1953 – 2009.

    The major point (1) put forward by Walt Meir can now be tackled, i.e.” The error in no changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.”

    The second sentence is true – the Artic sea ice extent has declined significantly and the ice has thinned, but this also happened in the early late 1950s and early 1960s. So it is not uncommon.

    The first sentence is wrong – the exclusion of data for the period 1953 to 1977 has led to an erroneous conclusion about the long term changes. The trend in Artic Sea ice is not signficant.

  122. Antonio San says:

    Foinavon, thank you for informative links. Yet they still do not answer my question: where is the 100y old arctic sea ice if not melted through periodic melt events making the latest one we observe now far from unprecedented?

  123. AKD says:

    Thanks for the post Dr. Meier.

    Just to be clear: one of the leading indicators of anthropogenic global warming is a somewhat weak local trend over the period of a few decades?

  124. CoRev says:

    Any sinusoidal system, Arctic Sea Ice is one, would by its nature pass through its average ted line twice each cycle. Arctic Sea ice has an annual cycle. What George Will and Asher did was take two points in that historical record where the amounts/data matched. Coincidentally, their selected dates were near the ends of the data collecting periods.

    Their analysis was correct! It could have been correct for any year. What was serendipitous for them was the dates and data matched (very closely) at the ends of the data collection period.

    Compounding this analysis issue is that the upper limits of annual growth of Arctic Sea Ice is limited by the land boundaries. So, any analysis could have found many dates when the Arctic sea ice was area/extent were equal.

    They’re crime? To imply that it indicated that Arctic Sea Ice was growing AND didn’t support AGW.

  125. DaveE says:

    Allan M R MacRae (19:00:25) :

    “We know that 1934 was the warmest year in the lower 48 states of the USA.”

    I suggest you check GISS Allan. Last time I checked, it was tying with 1998.

    DaveE.

  126. Rebar says:

    From the Revkin link:

    Dr. Jennifer Francis, Rutgers:

    “Any change in a single year — no matter what the variable — cannot generally be linked to climate change, although the ice losses in 2007 and 2008 would not have happened without the long-term warming and thinning of the ice cover.”

    Once again, only global warming can be supported by anecdotal, single point events.

  127. foinavon says:

    Eric Anderson (07:39:27) :

    How does new ice accumulate on pre-existing ice? Does it grow in the water from underneath? Other than some minor amount of snowfall from above that might get compacted into ice, it seems there wouldn’t be any “thickening” from above.

    Good question. I have naively assumed that preexisting sea ice thickens from below (by continual freezing of the bottom parts, although this should be somewhat insulated from cold air temperatures above the ice) and from above (by compacting of snow or freezing of snow meltwater). However I’m no expert on this by any means, and might be totally wrong.

    This page is quite informative and might help:

    http://www.arctic.noaa.gov/essay_wadhams.html

  128. gary gulrud says:

    “I found this to be fairly humorous as the total global sea ice ‘AREA’ decline over 30 years is only about 4% by data I downloaded from NSIDC.”

    I think the data, in any event, are not particulary important to their scientific process.

  129. MartinGAtkins says:

    jlc (07:23:43) :

    In addition, the numerous typos and grammatical errors do little to inspire confidence.

    An Ad Hominem is a general category of fallacies in which a claim or argument is rejected on the basis of some irrelevant fact about the author of or the person presenting the claim or argument.

    He’s a scientist not a journalist.

  130. Rocket Man says:

    DaveE (08:25:32) “I suggest you check GISS Allan. Last time I checked, it was tying with 1998.”:

    DaveE, At one time GISS had 1998 the hottest year, then it was 1934, now they are tied (I will take your word for that as I don’t bother with GISS). Hanson does so many adjustments to the temperature data that his outputs cannot be relied upon to give you any idea what historical temperatures were.

    The way Hanson plays fast and loose with data for GISS Temp is one of the reasons that people question have started questioning any suspicious data from the Climate Community.

  131. Policyguy says:

    Mike B and Steve K,

    Then perhaps we can ask Anthony to add this Q to his list when next he communes with Dr. Meier.

  132. MarkW says:

    The arctic sea ice record is only 30 years old.
    Thirty years ago the PDO had just switched from cool phase to warm phase. It has just recently switched back.

    The idea that we have been observing the arctic long enough to draw any conclusions about what sea ice is doing, is just plain ridiculous.

  133. Phil. says:

    Mike Bryant (04:11:38) :
    Policyguy,
    Nope, nevergot an answer from Meier or Chapman. Apparently, Dr. Meier only cares if his data is used to promote common sense.
    Mike Bryant

    There’s no reason to believe that the areagrid.dat file has been changed since ’78. So the differences you see in the presentation of the images don’t imply any effect on the graphical data.

  134. foinavon says:

    Antonio San (07:55:04) :

    Foinavon, thank you for informative links. Yet they still do not answer my question: where is the 100y old arctic sea ice if not melted through periodic melt events making the latest one we observe now far from unprecedented

    I’m not sure if there is any 100y old arctic sea ice Antonio. According to Maslanik et al., the oldest areas of ice are in sectors 6-8 (their designation – see Figure 1 of their paper [***], which is the Western arctic in regions the adjacent to the Canadian Archipelago and in the eastern Beaufort Sea. I guess if there is any, that’s where it would be.

    But I’m not sure whether ice ever gets to be 100 years old anyway. The Arctic ice sheet is not static and parts of it move in great circuits or are transported across the Arctic basin. So it might be the case that there is a limit on possible ice age defined by the rate at which old ice is transported into regions where significant melt is likely whatever the climatic conditions. This is explained here:

    http://www.arctic.noaa.gov/essay_wadhams.html

    see the section: “What happens to the ice that survives?”

    For these details we really need an expert. I’m not keen on making assumptions/interpretations over and above what I can read and understand!

    [***]Maslanik JA et al. (2007) A younger, thinner Arctic ice cover: Increased potential for rapid, extensive sea-ice loss Geophys. Res. Lett. 34, L24501

  135. foinavon says:

    DR (06:17:02) :

    Let’s guess foinavon, the arctic sea ice conditions are “unprecedented” in human history, and irreversible due to increases in atmospheric CO2, right? That is of course unless we take drastic action, high taxes and government control, to curb the inevitable catastrophe………..predicting doom…..workfare for otherwise unemployed scientists……….The sow’s teets are swollen from the milk of public treasure…..etc. etc.

    DR, why does simply citing a few papers that address specific points raised by others induce you to an outpouring of politicking (and btw, surely “sows” have “teats” and not “teets”)? This is a scientific issue, and we should address the science if we’re going to make meaningful conclusions. None of the articles I cited are “predicting doom”…they’re just reporting observations.

    It’s worth pointing out that our understanding of these issues comes from many 100′s of published studies and not a handful of papers around which “set piece” “battles” have been instigated in the blogosphere. You can be sure that scientists, policymakers and their scientific advisors are addressing all of the science, and probably very few of them are thinking about sows and their “teats”!

  136. Brian Johnson says:

    Most Green protests around the world seem to aim at cutting man made CO2 levels.
    As that, taken to the maximum anthropogenic yearly output is only 3% of the total……….and which will cost trillions at a time when the whole world is in recession, seems utterly futile and equally, mind numbingly dumb!
    President Obama, from the other side of the Atlantic is being led by a bunch of political numpties and they are his choice. A petard , a hoist, may well be trundled up to the White House in the not too distant future. Plenty of brownouts to come and “Brown Out” is what we want in the UK. Gordon Brown is our Prime Minister and will be gone long before your President……..
    I wonder when the penny will finally drop and mega expensive renewables get kicked into touch and the huge economical reserves of oil/coal are used to best effect? Then build modern Nuclear Power Stations and ignore the Gore/Hansen/Moore smoke and mirrors hysteria.

  137. jlc says:

    mga (08:57:43) :

    Did you read what I wrote?

    Maybe not, but no prob. We set the bar a bit lower for “climate scientists” relative to us engineers, as has always been the case.

  138. jlc says:

    MarkW (09:14:09) : – thank you for saying what I was trying to say in terms understandable to mga (and our mate wally)

  139. An Inquirer says:

    DaveE: “I suggest you check GISS Allan. Last time I checked, [1934] was tying with 1998.”

    No doubt, numerous posts will comment on this statistic, but in my understanding, 1998 is sometimes claimed to be in a virtual tie with 1934 although 1934 is a tiny warmer. However, I would point out that actual temperature observations put 1934 considerably warmer — GISS adjustments put it down lower to virtually tie with 1998.

  140. Mike Strong says:

    Comments for Dr. Meier:

    1. His statement: “I write here from my personal viewpoint and not in an official capacity as a representative of NSIDC or the University of Colorado”. You work there and you are talking about intellectual data derived from your position there. You can’t take off your NSIDC hat at will…you wear it 24/7 as long as you serve in any capacity there. I want to tell that to James Hansen also, in regards to using his position at NASA to further his political agenda and megalomania.

    2. I still want to know why…and if confounds me…why the NSIDC uses the 1979-2000 as the numerical average (mean) in their trend lines. They basically throw out 30% of their 30 years worth of data as if 1979-2000 is some sort of holy grail “normal” period of time. At least Artic ROOS uses 1979-2007. This is a small point, but showing the full 30 year average doesn’t make 2007 look like such a radical departure from the best “normal” of which we have very limited data. Remember, most news reporters are not well paid, nor are they good at science and graphs and charts, when they say “OMG! 2007 was really bad compared to normal years!”

  141. RickA says:

    Dr. Meier:

    Thank you for posting here.

    One of the things that puzzles me as a layperson (and lurker) is the significance of the fact that ice extent is declining and the ice is thinning.

    Is this the first time in history that the ice extent in the artic is declining and the ice is thinning – I suspect not.

    I suspect that the ice extent goes up for a period of time (say 30 years) then the ice extent goes down for a period of time (say 30 years).

    I would like to see this decline compared to say the previous 10 declines (or even the last decline – or the decline in the 1920′s or 1930′s). Why do we think this decline will not stop – but keep going for the foreseeable future. Is this decline being going on longer than the last 10 declines? Are we significantly below the trough or low point of the last 10 declines?

    My sense is that we don’t have the data to answer these questions. My sense is we don’t even have enough data to compare this to the decline of the 1920′s or 30′s. My sense is that until until we have been gathering high quality artic ice data for a much longer period of time than we have to-date (say 100 years or so) – we will not be able to put the current decline into context with the natural cycle – and measure how much Man is affecting the climate.

    I would like to see us gather a lot more climate data before we make policy decisions which will cost a lot of money – based on a pretty skimpy set of data that we currently possess.

    What are your thoughts on that?

    If does seem that artic ice extent is declining currently – one only has to see that the last 8 years or so of ice data are below the long-term average to see that. However, it also seems like the ice extent of the last couple years is above the ice extent 5 or so years ago.

    So maybe we are switching from a declining trend to a rising trend?

    If we check back in 2050 or 2100 we will know for sure.

    We will for sure have more high quality data – which was gathered through both a down trend and a rising trend – which will better inform both the models and conclusions.

  142. foinavon says:

    Malcolm (07:50:30) :

    Walt Meier: ” The error in no [way] changed any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.”

    Malcolm: The second sentence is true – the Artic sea ice extent has declined significantly and the ice has thinned, but this also happened in the early late 1950s and early 1960s. So it is not uncommon.

    The first sentence is wrong – the exclusion of data for the period 1953 to 1977 has led to an erroneous conclusion about the long term changes. The trend in Artic Sea ice is not signficant.

    However you are basing that interpretation on a paper by John Walsh published in 1979. Walsh himself has reassessed his analysis in a paper published 2001[***] , has pointed out that his previous analysis (the 1979 Walsh/Claudia Johnson paper you link to) was limited in spatial extent, and that several new data sets allow extending the Arctic ice extent both more extensively in a spatial sense (i.e. covering much more of the arctic region) and back in time to the start of the 20th century [see foinavon (06:55:40) ].

    His extended and revised analysis is shown (and further extended from 1997 to the present) here:

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

    [***]Walsh JE and Chapman WL (2001) 20th-century sea-ice variations from observational data Annals of Glaciology 33 444-448

  143. foinavon says:

    RickA (09:59:05):

    I suspect that the ice extent goes up for a period of time (say 30 years) then the ice extent goes down for a period of time (say 30 years).

    I would like to see this decline compared to say the previous 10 declines (or even the last decline – or the decline in the 1920’s or 1930’s).

    The data is here. Note that the pre satellite data is based on numerous series of observational data of sea ice extent (from ships logs, meteorological data from the UK, US, Canada, Denmark, the Icelandic Glacialogical Society, Norwegian Polar Institute sea ice charts etc.- that sort of thing)

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

  144. schnurrp says:

    Rebar (08:42:01) :

    From the Revkin link:

    Dr. Jennifer Francis, Rutgers:

    “Any change in a single year — no matter what the variable — cannot generally be linked to climate change, although the ice losses in 2007 and 2008 would not have happened without the long-term warming and thinning of the ice cover.”

    Once again, only global warming can be supported by anecdotal, single point events.

    There is “global warming” and “a pause in global warming” only.

  145. DaveE says:

    Rocket Man (09:03:30) :

    “DaveE, At one time GISS had 1998 the hottest year, then it was 1934, now they are tied (I will take your word for that as I don’t bother with GISS).”

    The correction making 1934 hotter was done grudgingly at the prompting of Steve McIntyre.

    “Hanson does so many adjustments to the temperature data that his outputs cannot be relied upon to give you any idea what historical temperatures were.”

    Exactly my point.

    An Inquirer (09:45:29) :

    “GISS adjustments put it down lower to virtually tie with 1998.”

    No longer. Last time I checked it was tying to 0.01ºC

    DaveE.

  146. Smokey says:

    foinavon not surprisingly picks only the Northern Hemisphere to try and make his case.

    Here’s the relevant comparison, between December 1979 and December 2008 …for the entire planet:

    December 1979 ice extent, S.H.

    December 1979 ice extent, N.H.

    December 2008 ice extent, S.H.

    December 2008 ice extent, N.H.

    Total ice coverage is almost a million square kilometers greater now than in 1979.

  147. K says:

    Dr. Meier could certainly given a shorter reply. And perhaps a more polished one. But he sent an informal communication and I wouldn’t infer much from it.

    So the sensor failed. He apologizes. He includes the mandatory self-praise of staff which one encounters in virtually any communication with a government entity. They always say they are very skilled and hard working and conscientious. And they don’t have enough money so they brilliantly set priorities to achieve the best results.

    And one must expect this from time to time. They do.

    A more familiar defence, not used by Meier, is “Who knew, this was totally unpredictable and unprecedented”.

    The boiler-plate-filler or official-speak is a bit silly. But you must endure it when dealing with government. And sometimes it is true. Make no judgement here.

    I don’t see that Meier disputes anything about Arctic ice. He says it is in a long-term decline. Period. The science is settled. The definition of “long-term” ?

    He is talking about quantity of ice – which must consider thickness – and not extent or area. The extent or area can and will fluctuate somewhat independently of quantity.

    Unfortunately he wrote “extent” not quantity or amount or mass.

    I would restate the Arctic Ice situation as this. The data for measuring extent and area is now public. That science or technology is good enough.

    The measuring of thickness is less public and less settled but that is what counts and where more information is needed.

  148. Rob says:

    foinavon, However you are basing that interpretation on a paper by John Walsh published in 1979. Walsh himself has reassessed his analysis in a paper published 2001.

    I don`t suppose this reassessment has anything to do with funding, who peer reviewed that study.

  149. Speaking as a scientist who worked with climatic data for over twenty years, if misplacing a chunk of ice the size of California results in…

    “The error in no changed {sic} any of our conclusions about the long-term changes in Arctic sea ice. The ice extent is declining significantly and the ice is thinning.”

    I’d say that Dr. Meier and that clown Hansen would be better suited to a job where they ask the public, “Do you want fries with that?”

  150. David Porter says:

    Dr Meier,

    If you need a backstop to keep all us riff raff at bay you could employ foinavon. You might be happy because he knows everything about everything and we certainly would because we could escape the constant patronising.

  151. foinavon says:

    Rob (11:25:16) :

    foinavon, However you are basing that interpretation on a paper by John Walsh published in 1979. Walsh himself has reassessed his analysis in a paper published 2001.

    I don`t suppose this reassessment has anything to do with funding, who peer reviewed that study.

    No. It had nothing to do with funding or who peer-reviewed the study. What an odd view! As Walsh states in his 2001 paper, the updating of his 1979 study resulted from the identification of new data compilations in the following 20-odd years that allowed the original limited regions of the Arctic to be extended to cover a much larger region and to be extended back in time to the start of the 20th century.

  152. Jim Clarke says:

    After wading through all of this, I think it is safe to say that the Arctic sea ice has been thinning and and becoming less extensive since the late 1970s to 2007. Since then, the trend has reversed somewhat. Just like with the atmospheric sounders, the failure of the satellite ice sensors gives one pause. In other words, how much of the trend is the result of sensor issues? A post describing a visual observation from a plane of a frozen James Bay while the satellite still showed open water makes me wonder about the extent of the problem. These ‘failures’ were not sudden and complete, but gradual.

    Foinavon supplies some interesting studies about pre-satellite era ice extent, but my education predates the satellite era as well. I was taught that regional climate changed; that the MWP and LIA were real and that Arctic ice also changed. The studies of that era provided convincing evidence. I find it strange that studies conducted in the present era of global warming funding all report NEW ‘old data’ that show NO CHANGES! Granted, detailed information about arctic sea ice is sketchy at best before the 1970s, so perhaps one can skew the data anyway they want.

    It is interesting that good historical data in places like Europe and the US always show a cyclical climate, with some periods warmer and some periods cooler. It is only in areas where the data is not good, like remote geographical regions or in the distant past, that we are asked to believe that the climate was stable, even when there is ample anecdotal evidence to the contrary.

    The bottom line is that the Earth seems to have been in a general warming trend for over 200 years. Increasing CO2 could not possibly be blamed for the first 120 years or so. For the last 80 years, the warming seems to be in lock-step with the PDO/AMO combination and perhaps an active sun, leaving only a minor influence from CO2. I am troubled that Dr. Meier makes it a point to say the the observations are consistent with the theory of man-made global warming. Yes, but the observations are far more consistent with the theory of natural/cyclical warming.

    A scientist should always go with the theory that explains the observations most effectively. Clearly, increasing CO2 is not the only explanation for what we are observing, or even the best. The fact that federally funded scientists are almost universally myopic on possible explanations for global climate observations is strong evidence that man-made global warming is fueled by grants and not CO2.

  153. Antonio San says:

    Foinavon, thank you for the exact quote by Dr. Maslanik. Indeed if arctic sea ice is unlikely to reach the venerable age of 100y old, it confirms regular processes conspire against it and do not allow it to happen. Observing in details never documented before the result of strong warm air advection and its modest interaction with sea ice by no means exclude a similar process did not occur in the past before satellites offered day to day variations -hopefully reliable-. Again the climatic shift to a rapid mode of circulation observed by Leroux and confirmed by Pommier 2005 in the North Atlantic, by Fravre & Gershunov in 2006,2008 in the Pacific very naturally explains the arctic ice patterns. Indeed even Dr. Meier in his monthly report mentions the atmospheric circulation and winds…

  154. Phil. says:

    DaveE (10:28:02) :
    Rocket Man (09:03:30) :

    “DaveE, At one time GISS had 1998 the hottest year, then it was 1934, now they are tied (I will take your word for that as I don’t bother with GISS).”

    The correction making 1934 hotter was done grudgingly at the prompting of Steve McIntyre.

    Another myth, Hansen always said that 1934 held the record for the US, he didn’t make any correction to the data to make it so.

  155. Jim Powell (07:01:55) :

    Re: http://people.iarc.uaf.edu/~sakasofu/pdf/recovery_little_ice_age.pdf .

    Thank you for pointing out this article. I urge everyone here to read it. Please. It is long but worth it. I especially liked the incredible ability of GCM’s to hindcast the observations (NOT). Interesting indeed.

    That’s the most interesting climate paper I’ve read so far this year. It seems perfectly logical, very well supported by data, flows very well from data to conclusions, and contradicts the IPCC on a number of counts, even if doing so in a polite way.

    Prediction: It will be difficult if not impossible to find a publisher. Radical departure from the prescribed dogma. Makes entirely too much sense and does not need or use undecodable algorithms to make its point. Clear. Direct. Transparent. Obvious. These are not the qualities of a worthy climatology paper… are they? I mean who goes around using “old” data anyway? This stuff hasn’t even been homogenized or anything… We want “fresh” data.

    I’d love to see the peer review comments. What are they going to say to a paper like that?… “We know you’re right, but it contradicts everything we’ve already told everyone. Sorry pal. Bring it back when it says it’s all CO2. Gotta run, here comes my jet.”

    Great paper. Thanks again.

  156. Philip_B says:

    foinavon, the 3 studies you show support my point that, The ‘ice is thinning’ argument is mostly inference.

    Those studies are (mostly) about one year, 2007, have direct measurements of ice thickness in only small areas which are known to melt on an annual basis, and rely on ‘proxies’. Proxy meaning infering ice thickness from ice age.

    I realize the ‘thinning Arctic ice’ is dear to the hearts of Warmers everywhere, but there is no good evidence that Arctic ice is thinning over any period longer than 1 or 2 years or over the Arctic as a whole.

  157. Roger Knights says:

    Jim Powell:

    Thanks for the link to the 52-page paper, “The Recovery from the Little Ice Age”:
    http://people.iarc.uaf.edu/~sakasofu/pdf/recovery_little_ice_age.pdf

    Here is its Abstract, to tempt others to dip into it:

    “Two natural components of the presently progressing climate change are identified.

    “The first one is an almost linear global temperature increase of about 0.5°C/100 years (~1°F/100 years), which seems to have started at least one hundred years before 1946 when manmade CO2 in the atmosphere began to increase rapidly. This value of 0.5°C/100 years may be compared with what the International Panel on Climate Change (IPCC) scientists consider to be the manmade greenhouse effect of 0.6°C/100 years. This 100-year long linear warming trend is likely to be a natural change. One possible cause of this linear increase may be Earth’s continuing recovery from the Little Ice Age (1400-1800). This trend (0.5°C/100 years) should be subtracted from the temperature data during the last 100 years when estimating the manmade contribution to the present global warming trend. As a result, there is a possibility that only a small fraction of the present warming trend is attributable to the greenhouse effect resulting from human activities. Note that both glaciers in many places in the world and sea ice in the Arctic Ocean that had developed during the Little Ice Age began to recede after 1800 and are still receding; their recession is thus not a recent phenomenon.

    “The second one is the multi-decadal oscillation, which is superposed on the linear change. One of them is the “multi-decadal oscillation,” which is a natural change. This particular change has a positive rate of change of about 0.15°C/10 years from about 1975, and is thought to be a sure sign of the greenhouse effect by the IPCC. But, this positive trend stopped after 2000 and now has a negative slope. As a result, the global warming trend stopped in about 2000-2001.

    “Therefore, it appears that the two natural changes have a greater effect on temperature changes than the greenhouse effects of CO2. These facts are contrary to the IPCC Report (2007, p.10), which states that “most” of the present warming is due “very likely” to be the manmade greenhouse effect. They predict that the warming trend continues after 2000. Contrary to their prediction, the warming halted after 2000.

    “There is an urgent need to correctly identify natural changes and remove them from the present global warming/cooling trend, in order to accurately identify the contribution of the manmade greenhouse effect. Only then can the contribution of CO2 be studied quantitatively.”

  158. Ben Lawson says:

    Michael D Smith / Jim Powell / Roger Knights: “The best overall explanation that I have read so far is by Dr. Syun-Ichi Akasofu”? I hope you’re wrong about that because it probably WILL have a tough time getting into a peer-reviewed journal. 52 pages! Journals have budgets to meet, and favor concise, focussed submissions regardless of merit (or “in-crowd” popularity).

    As an aside, what is with all this rhetoric of exclusion? “They” won’t publish the skeptic’s “truths” because it goes against “prescribed dogma”? Pure sour grapes. Show me ONE journal editor or scientist who wouldn’t LOVE to be hailed for writing or publishing research that replaces conventional understanding with a better one. At the “pointy end” of science, that’s what it’s all about.

    Back to the lauded paper. The first paragraphs flat-out state that the IPCC is wrong and ascribe natural causes in defiant italics. Soon we see straight lines “intuitively” assigned to curving data trends (this shows up often in the paper). The interpretation of CO2 data charted on page 5 ignores the concept of rate of change while trying to prove that CO2 and temperature are not linked.

    Fundamentally this is argument, not science.

    My mind started to wander, as I am learning here that I’m quite dim-witted and emotional, but it is clear that he’s pulled together a lot of data sources, particularly on anecdotal glacier retreats (I’m not saying this critically). One thing, by chance, did catch my eye on page 16. The blossoming dates of Japanese cherry trees is described as indicating a linear temperature increase from 1830 but to me it seems clearly flat until the middle of the 20th century when it turns notably upward. It’s just one data set among many, and comically refers to actual cherries, but it’s awkward for his premise of purely natural and linear recent temperature trends.

  159. gerrym says:

    Ben Lawson:”Show me ONE journal editor or scientist who wouldn’t LOVE to be hailed for writing or publishing research that replaces conventional understanding with a better one. At the “pointy end” of science, that’s what it’s all about.”

    I don’t think I’d be too willing to publish a paper refuting the editorial line I’d been following for a number of years. An editorial line which had in fact been followed and adopted by politicians all over the world with the results that citizens everywhere were being taxed good dollars on the forecasts of my contributors.

    Nature refused to publish McIntyre and McKitrick 2005, firstly because it was too complicated and then because it was too short. That paper’s conclusions were subsequently endorsed unequivocally by an eminent statistician and by Gerry North of the NAS. (who it has to be said has since watered down his endorsement once out of the glare of public gaze).

    Another reason could be that the editor holds a scientific view contrary to the proposed paper, I believe you’ll find that Robert Hooke, when president of the Royal Society refused to publish a paper on the nature of light put forward by Issac Newton which proposed that white light was made up of multiple colours. Hooke, and the scientific consenus of the day believed that white was the purest form of light so simply refused to publish the paper.

    Newton’s revenge was to say, “If I have been able to see a little further, it is because I have stood on the shoulders of giants.’

    Hooke was a diminutive hunchback.

  160. Allan M R MacRae says:

    DaveE (08:25:32) :

    Allan M R MacRae (19:00:25) :

    “We know that 1934 was the warmest year in the lower 48 states of the USA.”

    I suggest you check GISS Allan. Last time I checked, it was tying with 1998.

    DaveE.

    Thank you Dave,

    It’s difficult to keep up with all the changes in GISS data. Last I read, Steve McIntyre found serious errors in the GISS data and caused GISS to admit that 1934 was warmer than 1998 for the “lower 48″. I don’t use GISS ST data – too many problems with lack of quality. Anyway, let’s assume 1934 and 1998 are now considered a tie by GISS, as you say.

    Global average surface temperature (Hadcrut3 ST) shows ~0.2C more warming than lower tropospheric temperature (UAH LT) since 1979. This suggests a warming bias of ~0.07C/decade for global ST. See Figure 1 at
    http://icecap.us/images/uploads/CO2vsTMacRae.pdf

    Adjust to the lower 48 land-only area, and the ST warming bias will be much greater than this global average bias. Michaels and McKitrick (2007) suggest a global warming bias for land-only ST’s of 0.13C/decade.
    http://www.uoguelph.ca/~rmckitri/research/jgr07/M&M.JGR07-background.pdf

    For the 5.5 decades between 1934 and 1998, the land-based warming bias is ~~0.7C.

    I would conclude that ST for the lower 48 was much (~~0.7C) warmer in 1934 than 1998.

    This conclusion is further supported by historical evidence. Does anyone remember a huge US Midwest drought in 1998? No? How about in the 1930′s? John Steinbeck, “Grapes of Wrath” and all that.

    Regards, Allan

  161. Roger Carr says:

    Allan M R MacRae (19:00:25) – Steady, Allan, spreading this kind of material risks spoiling the best scam since Tulipmania.

  162. thefordprefect says:

    Smokey (10:32:45) :
    Why december – juiciest cherries?!

    Heres a plot showing average september total sea ice for N S hemispheres:
    http://img27.imageshack.us/img27/3866/totalnsseaiceextentsept.jpg

    This shows 1979 toal sea ice as 25.5 and 2008 toal sea ice is 23.17

    data available here:
    ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/
    Mike

  163. thefordprefect says:

    The arctic sea ice is limited in max extent by land
    The antactic is the opposite the min extent is limited by there being no more ice to melt

    Changes in the arctic maximum will be compressed
    Changes in the antactic minimum will be compressed
    Mike

  164. To (partly) echo Anthony’s first comment, this essay is a breath of fresh air compared to some other posts.

    Glad to see the big picture clearly stated here: “The ice extent is declining significantly and the ice is thinning.”

  165. Richard M says:

    What I find most intersting about the arctic ice extent is why hasn’t it been affected more?

    Clearly, it has not declined “significantly” or it could never have been equal to 1979 a couple of months ago. Why does it matter if it melts a little more in the summer than it did 30 years ago if it all freezes up again. There are literally dozens of reasons for this that have absolutely nothing to do with CO2.

    We know so little about the multitude of variables that impact climate. This becomes more apparent each and every day.

  166. Roger Knights says:

    Ben Lawson wrote:
    “Fundamentally this is argument, not science.”

    But, if science = falsification–and purported falsification–then argument must be a large part of science. No?

  167. Roger Knights says:

    Bart Verheggen (13:17:42) :

    “Glad to see the big picture clearly stated here: ‘The ice extent is declining significantly and the ice is thinning.’”

    Append “since the 1970s” and you’ve alluded to an even bigger picture. (Ditto with surface temperatures.)

  168. Sarah says:

    I recently came across your blog and have been reading along. I thought I would leave my first comment. I don’t know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.

    Sarah

    http://www.craigslistdecoded.info

  169. Smokey says:

    Bart Verheggen, When you said…

    Glad to see the big picture clearly stated here: “The ice extent is declining significantly and the ice is thinning.”

    …you left out the pertinent fact that the comment only referred to the Arctic, not to global ice extent.

    That pretty much negates your “big picture.”

  170. Ben Lawson says:

    Roger Knights: “But, if science = falsification–and purported falsification–then argument must be a large part of science. No?” No is correct. “Science” is the systematic acquisition of knowledge about the natural world. “Falsifiability” is whether the predictions of a scientific theory can be tested to determine if they support or undermine it.

  171. Lex says:

    My point of view is perhaps not very scientific, but I’m glad to read that “old ice” is replaced by “new ice”. Just imagine what would happen if the “old ice” stayed and the “new ice” was added.

  172. Smokey says:

    “…argument must be a large part of science.”

    How can that not be true?

    Science progresses through observation and experiment, and is validated by replication, and by honest attempts to falsify the observations and experiments. This cannot be done without argument; debate, if you prefer. The goal is a meeting of the minds, which has certainly not happened in the climate debate.

    And that, my friend, is why skeptics are suspicious of AGW claims. Those making the AGW claims resist attempts to replicate their claimed observations and experiments, by not willingly archiving their data and methodologies for other scientists to review, which is necessary for the Scientific Method to work. Instead, they want everyone to simply take their word for it; the science is settled.

    Grant money, which is funneled primarily to those espousing the AGW/global warming hypothesis, and the well documented hijacking of the climate science peer-review process, has created a great deal of suspicion about all climate science.

    The responsibility for the public’s distrust must be laid directly at the feet of those who connive to promote their agenda. In their scheming for money and status, the small clique manipulating the system are unfairly making all scientists look dishonest.

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