NSIDC's Walt Meier responds on the sensor issue

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

“(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”)

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.

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.

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.

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?

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

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.”

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

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.

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.

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

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

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

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

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.

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.

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

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

I didn’t think my question was too bad.
Anyway, thanks for the article.

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

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”.

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.

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 ….)?

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.

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).

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.

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

(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.

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.

[snip – take that to email please]

“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/

Great Lakes Ice Coverage is interesting to look at also.
http://ice-glaces.ec.gc.ca/Ice_Can/GL/CVCSWCTGL.gif

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.

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

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.

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

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?

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

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.

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 !

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

“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.

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.

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?

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

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?

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.

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)

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.

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.

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.

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.

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?

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.

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

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.

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.

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”!

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.

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.

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.

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

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.

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.

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?”

I think the NSIDC site covers the issue abut declining ice quite enough:
http://nsidc.org/arcticmet/patterns/arctic_oscillation.html
http://www.sciencedaily.com/releases/2001/07/010709074127.htm

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.

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…

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.

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.

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

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.