Cowtan and Way – The Magician's 'Red Scarf Trick' with Linear Trend Lines

Guest Post by Kip Hansen

There are a lot of good, in-depth technical discussions of Cowtan and Way 2013, Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends. This is not one of them. In this post, I only hope to demonstrate a trick I learned when a young man, when I was a semi-professional performing magician. It is meant to be fun even though is makes a very valid and necessary point. I will use C&W 2013’s results graphic from their Media Summary:

clip_image002

Caption: “Temperature data from the Met Office (thin lines) compared to the optimal Cowtan and Way (2013) global reconstruction (thick lines). The straight red lines indicate the trend over the past 16 years in the respective data. The background image illustrates the coverage of the Met Office data, with colours indicating geographical temperature trends. The Arctic is warming much faster than the rest of the planet.”

It is followed by the statement: 

“The temperature change for any individual year is not very large (and less than the Met Office uncertainty estimates), but together they make a significant difference to recent temperature trends. This highlights the danger of drawing conclusions from trends calculated over short periods.”

As in all good performances of the Magician’s Art – you may have failed to notice that the trick has already taken place. You can read the amazement in the MSM and on the climate blogs – they are all agog at the marvelousness of it. Even their detractors [for the most part, there are exceptions] and the skeptical, see clearly that a low bias in determining missing surface temperature values in the Arctic has caused Global Temperatures to be understated.

Now, please, I make no claims as to the intentions of Cowtan and Way. I only claim to illustrate a simple little point using their recent paper’s abstract and their kindly provided background materials.

It is considered worse-than-poor-form to show how a magic trick is done, either before or after it is performed. But in this case I must – it is the point of this essay.

C&W state explicitly above “This highlights the danger of drawing conclusions from trends calculated over short periods.” Well, of course it does. In the world of performing magic, in the old style, patter, the words spoken by the performer, supplied a great deal of the distraction and misdirection required to make the magic acts work. This bit, used by C&W, is “the denial” — in which the performer formally and explicitly denies that he is going to do something to trick the audience, even at the very moment that he does that exact thing.

If I were performing a similar trick, as a stage magician, you would have heard me say something along the lines of

“Dear friends, you all know that the acts of magic I perform are all tricks – many of you don’t really believe in Magic. You may think I’ll attempt to distract you while fooling you in some way. Rest assured, this is not so….I invite you to watch closely my every move. You may find there is magic after all. Look, there is nothing up my sleeve, nothing in my hat. [Carefully exaggeratedly displaying sleeve and hat] Now, look at this beautiful silk scarf [magician spreads it for all to see, then tosses the three foot square of brilliant red silk high into the air, following with his eyes]. Nothing in there either.”

Note: The manual for this card trick calls for the Magician to switch the deck of cards that has been previously inspected by the dupe, by this method: While displaying the scarf, the magician sweeps the inspected deck of cards into the hidden black well built into the table with the left hand and dropping in its place a new deck, palmed from wherever is convenient. All of this while pointing at the red scarf with the right hand, following the path of the flying scarf with his eyes and an exaggerated tilt of his head. The new deck, of course, contains cards in the carefully pre-arranged order required by the magician for the trick at hand.

Some magicians call this move “the follow”, others simply “the distraction”. The audience’s eyes will follow the scarf, look where the magician points, and look where he looks. I have never had even the most skeptical audience (not even ‘tweenage boys) catch me at this.

Having read a half-dozen or more blog posts on C&W 2013, and hoping to understand it better, I followed links to their Background materials. The instant I saw the graph above, I exclaimed out loud to my wife “Look, they’ve used the old ‘Look at the red scarf’ trick!” (I repeat, I have no information or opinion on whether or not they have done this intentionally.)

Here’s the graphic without the “red scarves”:

clip_image004

Now what do you see?

What we don’t see is what C&W claim: “Temperature data from the Met Office (thin lines) compared to the optimal Cowtan and Way (2013) global reconstruction (thick lines). The straight red lines indicate the trend over the past 16 years in the respective data.”

Quite honestly, you don’t see such a trend or differences in such trends because there is no reason to look at this graph in that particular way and their claim honestly is not clearly demonstrated by their graphic or their work. The two trend lines are the red scarves. Both trend lines are the same trick, in reality, but for their desired effect, the one they want you to focus on is thicker and bolder, to highlight the difference in slope over 16 years. Yet, their whole work is a new calculation of global temperatures using their new technique for evaluating missing data points in spatial coverage of the Arctic, over a 33 year period. They have caused you too look at the red scarves (supplied trend lines) and not the whole graphically presented data set.

And, that, my friends, is the trick using The Red Scarf Follow, C&W got us to see something that without the trick, we would not have seen at all and to not see the rest of what they have done.

[That’s it, Magic Fans….the rest is a bit of commentary on what shows in the graph without the red scarves.]

Here’s what I see in their findings, you may see something different:

clip_image0064

[***Image modified 26 Nov 2013 adding in starred blue box: h/t comment from Bill_W ]

From 1979 to around 2005 or 2006, the new technique does not produce anything different than what we already had. Sometimes their data is a few hundredths of a degree higher, sometimes a few hundredths of a degree lower. If it had been any closer a match, I, for one, would have called foul….it would have been suspicious that a major change in the method would produce exactly the same results. There are no signs of a long-term bias—warm or cool—in the Met Office data compared to their new Global.

In 2005, 2006, and the first part of 2007 there seems to be some discernible differences, still in the one or two hundredths of a degree range, which disappear for a year or more beginning what looks like mid-2007 and lasts until 2009 (the right edge of the yellow box). There is something definitely different in the last few years of the data.

What that difference is, I don’t know, nor do I have any idea why it is different and only in those last few years……but it seems highly unlikely to me that a long-standing cool-biasing methodological error (regarding infilling or not of Arctic data) at the MET OFFICE becomes visible only in the last few years of a 33 year data set.

# # # # #

Moderation Note: This is not a technical thread, and has almost nothing to do with Global Warming, Climate Change, or Arctic temperatures, in-filled, ‘kriged’ or not. It is simply an observation and follows from my recent essays on trends in general. I will follow comments and answer questions on amateur magicianship but not on climate issues. I would like to see your thoughts on what you see in the graph, sans trend lines.

=============================================================

*** Addendum (26 Nov 2013): Moved up from comment by Bill_W: “There should be another box around the 1998-2001 region [added in blue in image above – kh]. There the new data is lower while in the more recent data it is higher. So the slope changes due to changes at each end in the 16 year time frame. The 16 year period also starts around the year 1998. This is ironic given how often that argument has been used to minimize the pause.” My reply was “Very perceptive ==> That is a good point and I did miss it. Their finding a ‘Met Office warm bias’ in the 1998-2002 period brings the [left]-hand side of their bold trend line down, increasing the slope to the raised ‘Met Office cool biased’ end years.” The combination of the two creates the oft-seen Climate Science graphical “trick” == The Pivot == cool the past and warm the present to make a rising temperature trend. ***

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phodges

Nicely done.

Joe Prins

And here I thought it was all about not showing Antarctica.

rogerknights

Typo in the first paragraph–“mean” should be “meant”:

It is mean to be fun . . . .

[Fixed, thanks. — mod.]

I’m not really sure what the point is here. If you take away the red lines, you see a thick curve which really doesn’t look as if it is pausing. Trend lines help to quantify that. Without the red lines, they probably would have used a contrasting color for the thin line (current HADCRUT). Then you’d see the contrasting pause pattern.
Is your point that the divergence is recent? Bob Tisdale and Steve McIntyre have noted that. But Arctic Winter Warming is strongly linked to melting sea ice. And there has been a lot of melting since 2005.

Janice Moore

Repeating a comment I made on another Cowtan and Way thread:
“And that, boys and girls, is why Santa Claus lives at the North Pole.”
******************************************************************************
Thanks for the fun, Mr. Hansen. Now, don’t go trying to make the clothes you’d prefer not to put away “disappear” under the bed — your wife will find them. Try sending them to the deep oceans — that’s what Trenberth does.d #(:))

AnonyMoose

Hey, look! They decreased the warming in the 18-year 1980-1998 period! It’s not as bad as they thought, but there’s no reason to draw trends over such short periods!

Janice Moore

Oh, Mister Stooookkkkkesss — yoo hoo…. .
Bless your heart, you forgot something!
Now, go back outside, hop on your bamboo bicycle (surely, you don’t drive a fossil-fuel burning vehicle,…. do you?!) and go home and fetch your…. SENSE OF HUMOR. Then, come on back and have FUN.
#(:))
Janice
[The moderator admits he, too, is unable to translate a #(:)) emoticon. Mod]

michael hart

“Moderation Note: This is not a technical thread…”

Chuckle. That almost sounds like an invitation to use some strong language…but I won’t. 🙂
I keep hoping that somebody is going to produce an update of that most excellent little book “How to Lie with Statistics”, by Darrell Huff. I think an author might actually be able to sell a tidy number of books, and it’s not as if there isn’t plenty of modern material to work with. I think your point could be improved by coloring the lines before and after the dates where the effect is apparent.
http://en.wikipedia.org/wiki/How_to_Lie_with_Statistics

RoHa

Were you a prestidigitator or a thaumaturge?

Mike Maguire

Now we know why climate scientists consult with a magician before submitting papers.
Michael Mann uses David Copperfield (:

Bernd Palmer

Where is the anthropogenic footprint?
For twenty some years, Met Office and C&W march in lockstep and suddenly they depart.

u.k.(us)

You drew this reader in with:
“There are a lot of good, in-depth technical discussions of Cowtan and Way 2013, Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends. This is not one of them.”……..
=============
Now I’ll read 🙂

ColdinOz

Nick Stokes says “And there has been a lot of melting since 2005.”
What about the melting since 1997 Nick. Why didn’t it apply then, and what about the stable trend in Arctic sea ice since 2007/2008. Why is it supposed to have continued when the sea ice trend is stable. 2005 to 2007/2008? Talk about straw clutching.

Jquip

Stokes: “If you take away the red lines, you see a thick curve which really doesn’t look as if it is pausing. ”
So are you saying he’s waving a scarf about the cherry picked range for linear trends?

scarletmacaw

Nick Stokes says:
November 20, 2013 at 7:55 pm
Is your point that the divergence is recent? Bob Tisdale and Steve McIntyre have noted that. But Arctic Winter Warming is strongly linked to melting sea ice. And there has been a lot of melting since 2005.

Yes, Bob and Steve have pointed out the slope change in 2005. What I find interesting with Kip’s presentation is that a significant change is not there except for the post-2009 divergence. Why does the whole difference show up in only three years?
Also, because melting ice absorbs heat in a phase change which doesn’t change the temperature, shouldn’t one expect there to be a lower air temperature anomaly in the Arctic in years when ice is lost. Extending land and higher atmosphere measurements over an area where ice is melting should not be expected to work correctly. This gets into the whole heat vs. temperature argument, but if global temperature anomaly average is one’s goal, then one can’t just waive away the effect generated by pouring heat into a non-temperature changing sink and expect the extrapolation to be physically sound.

Well, I got it wrong. When I saw “This highlights the danger of drawing conclusions from trends calculated over short periods.” I thought I had spotted the trick – say you weren’t doing something, in this case drawing conclusions from short term trends, and then do it. Well, maybe I wasn’t so wrong .. that is exactly what they did in a way, the red scarf was the short term trend. It’s just that I thought that seeing the short term trend was the main objective, but as Kip Hansen so entertainingly points out, the real objective was to take our attention away from the fact that their “new” data didn’t change the somewhat more meaningful longer term trend one iota. Clever.

Kurt Hanke

Aren’t C & W cherry picking? If I understand correctly, there have been a significant number of temperature measurement stations dropped from the average over the last few decades, without any accounting for how that altered the trend at all. Many of those stations that were dropped were from colder regions, so would that not have caused the global trend to rise? Why did they not focus on that issue along with whatever coverage is missing from the Arctic?

philincalifornia

Come on Stokes – when even the f-kin pseudoscience is 4th or 5th rate, isn’t it time to give up ?

RACookPE1978

Nick Stokes says:
November 20, 2013 at 7:55 pm

But Arctic Winter Warming is strongly linked to melting sea ice. And there has been a lot of melting since 2005.

But, SUMMER temperatures at 80 north (all days between 150 and 250 when the summer sun is actually shining) have been declining (according to the daily DMI reports) since 1959.
And, as of the beginning of November this year, 2013 had more Arctic sea ice extents area than any year displayed since 2002. (In the two weeks since, 2013 has slipped a bit behind a few other years. )
And, since Arctic sea ice is at most only 5 years old, any trend since 2008 is, well, meaningless with respect to “long term” sea ice.
And, Antarctic sea ice has now set an all-time high, and is on track to block the Straits of Magellan and Cape Horn in 8-10 years. (If Antarctic sea continues to expand at today’s rate of the past three years.)

I would certainly expect that if there was some kind of long-running observational bias that such a bias would suddenly exaggerate by 3 or 400% in the last few years.
Sort of like if I slouch down with my head by the window I won’t get a good reading on my car’s speedometer, & since my car gets wider over time, I would expect the divergence to increase towards the end of the observational period.

Jquip

philincalifornia: “Come on Stokes – when even the f-kin pseudoscience is 4th or 5th rate, isn’t it time to give up ?”
But that’s the scarf! Look, we’re talking about 0.103C per decade being the doom of mankind. But have you ever put that on a human scale? To get that temperature increase, on average, right now: Simply walk south from Croke Park to the Ranelagh neighborhood in Dublin, Ireland. It’s about 4km. Terrible hard to put the speed in scale at something this dreadful slow. But it means a common garden snail can make that distance in 50 days. 3600 days before the 0.103C of global warming does. It’s scarves all the way down.

Janice Moore

Wow, I sure showed up at the wrong party (again, sigh). I mistakenly (oops — blush) thought this was a thread for mostly cracking jokes and being silly. From all the serious science discussion above, I see that I was mistaken. I beg your pardon, Mr. Stokes…….. Mr. Stokes?………. MISTER STOKES! You can come back, now!!!! (at the rate he pedals his bike, he’ll be back in about 3 days……. with his copy of the Cult of Climastrology bible to read from Presdidigitations, chapter 5. Oh, boy that should be edifying — NOT.
************************************
@ Phil in California — lol. Bingo.
******************************
Dear Mod,
(Re: 8:02pm.) Ahem, that little face turned on its side:
#(:))
OR
((:)#
is supposed to be a girl with a bow on her head… . Representing, oh, hm, I just wonder? (smile)
Thanks for letting me know it appeared to be a meaningless string of chars.
And thanks, so much for all you do to make WUWT a great place to come learn (and crack jokes, er, sometimes….)
Gratefully yours,
Janice

ColdinOz says: November 20, 2013 at 8:49 pm
“What about the melting since 1997 Nick. Why didn’t it apply then, and what about the stable trend in Arctic sea ice since 2007/2008.”
Well, here is the WUWT plot. Yes, Arctic ice has been steadily declining. But for the minimum, 2005 was a dip, and it really dropped after 2006.
RACookPE1978 says: November 20, 2013 at 9:21 pm
“And, as of the beginning of November this year, 2013 had more Arctic sea ice extents area than any year displayed since 2002.”

Their analysis ended in 2012.

Manfred

RACookPE1978 says:
November 20, 2013 at 9:21 pm
And, Antarctic sea ice has now set an all-time high, and is on track to block the Straits of Magellan and Cape Horn in 8-10 years. (If Antarctic sea continues to expand at today’s rate of the past three years.)
You’d better believe that if they ever find a location for the Iranians to test their new nukes safely, this could be it. The Antarctic ice will simply NEVER be allowed to reach MSM sniffing distance of S.America.

jono1066

I tried to replicate the “trick” here in my small flat on the edge of hospital complex,
it works really well….
the problem I now have is what to do with all these stupid bunny rabbits and the 2 white doves, though I have to admit the the flowers came in handy.

Rabe

What I see when looking at the extremes of the black curves from ca. 1997 on (the start date for the trends to be shown) is that the thick one is [ low – low – low – low – same – same – low – low – high – high – high – high – high – high – high – high ] which leads exactly to the intended outcome. Before 1997 they are pretty mixed just and only to demonstrate “fairness”. Silly trick.

Disko Troop

Someone pointed out somewhere that Robert Way of Cowtown and Way fame was a co-author of the Cooktown and co 97% debacle . The Cook Consensus started out to prove a 97% agreement by any means and methinks this little gem of a paper started out to disprove a pause by any means possible. As our able contributor says: Look away…no science to be found here.

Alarmists are peddling a neat line in cognitive dissonance here. They’ve always been suspicious – if not dismissive – of satellite data sets because they failed to produce the warming they were after. Now, they’re using a satellite data set to get them out of a hole created by their favourite ground-based measurements. Oh, the irony.

Disko Troop

I might add that the level of sophistication in their tactics has gone up a notch. They have given up on the science as it has gone against them and changed to pure public relations . Grabbing the Headlines, getting in the soundbites, content free. Not waiting to argue the case but moving on. While we dither about over whether they are right or wrong they are off to the next demo, issuing the next press release. The 10,000 dead figure for Yolanda is still out there. Our Prince of fools, the gormless Charles, is still regurgitating the soundbites of 5 years ago. The original Marxists wrote the manual and our latter day acolytes are learning to follow it.

This post is a delight. I’m adding the graphs to my growing collection of global warming data fiddles.

jorgekafkazar

Ice loss in the Arctic (and elsewhere) is often the result of low humidities or other factors: wind patterns, soot deposition, etc. Of the possible causes, wind is probably the most powerful.
Grafting (however cleverly) one data set onto another is highly suspicious, particularly when trying to tease a putative signal out of one of the noisiest data sets on the planet.

Peter Miller

My statistics teacher at university used to love to show us how you could prove almost whatever you wanted with statistics, you just had to choose the right methodology, make it sound complex but logical, and wham there was your ‘proof’.
Leaving that aside, the alarmist cult are using the right strategy – from their point of view – to concentrate on the Arctic, as it is the only possible Achilles Heel in the sceptic armoury.
The magic here is to draw the reader’s attention away from the inconvenient events in the Antarctic and to ignore the fact there is something obviously fishy about their last 6-7 years’ interpretations.
However, the real magic is how this nonsense keeps all the grant dollars coming, unwillingly funded by the likes of you and I.

Ursus Augustus

Imagine a sine curve of some parameter vs time. By definition it oscillates about zero or, if there is an offset in the particular defining equation, about some constant value. That is the pure mathematical form.
Next imagine some phenomenon which exactly obeys a sine curve form and a group of researchers start to record data of the phenomonenon vs time over a certain experimental interval dictated by their budget. They return to their research institute, process the data, plot it out in x-y coordinates and start to statistically analyse it. They evaluate a line of best fit and this becomes part of their consequent publication. The line shows a clear mathematical trend of 0.x units per interval of time and there is much fanfare as they discuss the results at length and issue press releases indicating the potential implications of this trend should it manifest over time.
One problem – the mechanism output is actually of pure sine curve – so how can it have a non zero trend line? The answer is of course that the data record started in a ‘trough’ and ended on a ‘peak’ and the data points are being statistically analysed as if they are a set of ostensibly random data that is generated by an indeterminate mechansim.
The reality is that the mathematical modelling is completely disconnected from the actual mechanism but that the expediency arising from the need to publish and in a particular time frame has won out and a completely distorted, quite fanciful even puerile process has been applied and in turn takes a life of its own. The ‘skeptics’ are laughed out of town as being jealous losers or whatever as this is real data recorded by professional scientists who specialise in the matter at hand.
“Such is life” as a great contrarian once said.
I have seen almost exactly such published work regarding sea level oscillations associated with the PDO so just imagine what sort of drivel can be passed of as an LPU in some of the scientologicaliferous publications doing the rounds. You don’t need to be a Steve McKintyre to figure it out. Magic – hardly. Just pitch the show at a lay audience.

All this keeps reminding me of the Sex Pistols number:
” We were krigging in the rigging, krigging in the rigging,
krigging in the rigging, ‘cos there’s fsck all else to do”

(PUBLIC HEALTH WARNING: don’t listen to the lyrics if you sensibilities to rude language)

What I see, without the trend lines, is that temperatures are still flat since 2001.

Crispin in Waterloo but really in Ulaanbaatar

My grandfather was a prestidigitator and I thankfully inherited his bag of tricks. I like nothing better than working out how it was ‘done’.
The problem with that of course is that after a loss of innocence life is boring. I see the cherry-picked location, the cherry-picked methodology, the cherry-picked data length, the cherry-picked start and stop dates, cherry-picked red scarf (there many choices available – use the one that works best) and the baked-in conclusion that much against satellite data there is global warming in abundance. The pause has vanished like a sedated rabbit in a mirrored box.
The similarity of this to the stage magician is that we pay to be entertained thus. The dissimilarity is we pay the stage magician to entertain us while the staged magician picks our pocket with the assistance of one of his sidekicks, By Hook and By Cook.
No doubt the next paper will show that 97% of climate scientists believe there is no temperature pause after all. It is a real-life example of levitation: a ghostly rise with no visible means of support.

jmrsudbury

I just see that they shortened the length of the pause down closer to what the GISS record has. — John M Reynolds

Pierre DM

I think it would be easier to see if the graph were redone with the thick black line being thin red and the thin black line being thick black.
Backing these guys into a corner never works as they don’t care about real science. Soon the warmist’s will do what they did in the 70’s. Dump the global warming and switch cash cows based on cooling and food with the simple wave of a hand and a red scarf. Global Warming to Climate Change was the start. All they need is a reason why man is to blame for switching off the heat. No need to fight for CAGW Much easier to exploit women and children with sad faces than the Statue of Liberty half underwater.

Admad

Pick a trend, any trend. Not like this, like that. A-huhuhuhuh (end Tommy Cooper impression).

AGW predicts warming at the poles. Both poles. Warming at one and not the other makes the world warmer on average, but it at the same time falsifies yet another prediction of AGW. So, if C&W have shown that the Arctic is warming, then the lack of warming in Antarctica shows that AGW cannot be the cause.
What the author has shown is that C&W’s methodology only shows a difference at the endpoint. Which is exactly what would be expected if the data is doing any sort of averaging over time. At the end points the average is missing data to calculate the average, which distorts the values at the endpoint
Mike’s trick was to fill in the missing tree data at the end point with thermometer data, to make it appear the series was continuous, and thereby hide the decline. It appears C&W’s methodology has accomplished the same. Old trick, new magician.

catweazle666

So let’s chuck a few miscellaneous data sets into a pot and stir them up, pour out the mixture, rearrange to suit, throw up our hands in delight, and grandly announce that “it really is worse than we thought, we’re all gonna fry!”
Just looks like another attempt to “Hide the Decline” to me, the uptick in 2005 has all the characteristics of a Hokey Schtick.
To cap it all, it’s from the same stable as Cook & Lewandowski’s 97% conspiranoid fantasy drivel.
Somebody’s getting desperate.

Jeff

Ahhhh, so that’s where they learned how to hide the decline….
(As done by Heidi D. Cline [ok, Cullen, but close enough for jazz…])…

MarkB

ColdinOz says:
November 20, 2013 at 8:49 pm
Nick Stokes says “And there has been a lot of melting since 2005.”
What about the melting since 1997 Nick. Why didn’t it apply then, and what about the stable trend in Arctic sea ice since 2007/2008. Why is it supposed to have continued when the sea ice trend is stable. 2005 to 2007/2008? Talk about straw clutching.

From figure S4 in the CW supplement, they show essentially steady warming in the Arctic over the entire record. They show a dip in the Antarctic between 1995-2000 that probably has about as much of an effect on the ’97-’12 trend as infilling the Arctic temperatures. That shows up in the “magician plot” as suppressing the magnitude effect of the 1998 el Nino.
http://onlinelibrary.wiley.com/store/10.1002/qj.2297/asset/supinfo/qj2297-sup-0001-AppendixS1.pdf?v=1&s=6c3b3b2c0f122671aab5ccbc2a9650380cfad491

beng

A academic-exercise to split hairs down to planck-width.

Poof!
While you guys were distracted by this post, I was initiating the next Ice Age
Dr. Evil
(I hacked this guys account! — Evil Laugh)

Bill Illis

Here are the official sea surface temperatures for the Arctic from the NOAA OiSST V2 dataset. [Not the anomaly, but the actual temperatures].
Notice how they are physically explainable (as in it is consistent with sea ice conditions etc and yes there is some warming also consistent with sea ice conditions) and it is not really higher than Hadcrut4’s trends so there is no reason to up its trends by infilling some 1.5C increase.
ie. it is already properly accounted for.
And please show me where an extra 1.5C from Cowtan and Way 2013 can possibly show up without melting all the sea ice.
http://s12.postimg.org/dcxwvcgh9/Oi_SST_V2_Arctic_SSTs_Oct2013.png

Bill_W

You missed one thing. There should be another box around the 1998-2001 region. There the new data is lower while in the more recent data it is higher. So the slope changes due to changes at each end in the 16 year time frame. The 16 year period also starts around the year 1998. This is ironic given how often that argument has been used to minimize the pause.

Alan Robertson

Nick Stokes says:
November 20, 2013 at 10:03 pm
RACookPE1978 says: November 20, 2013 at 9:21 pm
“And, as of the beginning of November this year, 2013 had more Arctic sea ice extents area than any year displayed since 2002.”
Their analysis ended in 2012.
______________________
Are you smart enough to realize that by making that statement, you drove another nail into the coffin of your credibility?

MarkB

Bill Illis says:
November 21, 2013 at 6:35 am
Here are the official sea surface temperatures for the Arctic from the NOAA OiSST V2 dataset. [Not the anomaly, but the actual temperatures].

For what it’s worth, here is the 2 m air temperature per the DMI: http://climexp.knmi.nl/plotseries.cgi?id=someone@somewhere&TYPE=i&WMO=ghcn_cams_05_0-360E_60-90N_n&STATION=GHCN/CAMS_t2m_0-360E_60-90N&NAME=Index&KIND=season

MarkB

RACookPE1978 says:
November 20, 2013 at 9:21 pm
. . . And, as of the beginning of November this year, 2013 had more Arctic sea ice extents area than any year displayed since 2002. (In the two weeks since, 2013 has slipped a bit behind a few other years. )
And, since Arctic sea ice is at most only 5 years old, any trend since 2008 is, well, meaningless with respect to “long term” sea ice.

Minor point, but where are you getting Arctic sea ice extent? NSIDC shows 2008 with slightly higher extent for all of November relative to 2013. Also, I’ve never seen the 5 year trend rational before and would appreciate a explanation or reference on that.