RC's Dr. Eric Steig boreholes himself on Antarctica

This is something that needs wider circulation, hence its appearance here. I’ve been mulling over how to best present this, and decided there’s nothing I could do in the way of excerpts that still told the story effectively, so I decided to present it in full. I’m pretty sure Jeff won’t mind. Readers may recall Steig et al 2009 and its cover picture on Nature saying the whole of Antarctica is warming, and the skeptic response paper O’Donnel et al 2010 response demonstrating conclusively that the peninsula is warming, but the whole of the continent is not. The reason for this is the same flawed PCA flawed statistical methodology, similar to what was used by Mann to create the Hockey Stick.  Jeff Condon, co-author of O’Donnell et al 2010  tells the story at his Air Vent blog.  Andrew Montford also has a post on it where he opines about the Steig et al 2009 paper possibly being included in IPCC AR5. – Anthony

Proof and Genius

Posted by Jeff Condon

I know you guys missed me, Real Climate sure did. Eric Steig has written a letter to “The Guardian” (booming voice) in response to a Nic Lewis letter patiently explaining problems in an article written by yet-another-know-nothing with a keyboard.  Unfortunately for us, the article itself has been updated in response so we can’t read the original.  What is interesting about the exchange is Dr. Steig’s wild reply.

My bold. 

Nicholas Lewis (Letters, 28 August) complained that your report (Arctic ice melt likely to break record, 24 August) gave the impression that typical temperatures in Antarctica have risen as much as on the Antarctic peninsula.

While he is correct about this, his letter also refers to an outdated study of his, which argued that previous estimates of overall Antarctic warming were too high. In fact, the work of Lewis and co-authors has been proven wrong.

The relevant paper here is Orsi et al, Geophysical Research Letters, vol. 39, 2012, which shows that the rate of warming in west Antarctica is as great, or greater, than what we showed in our original work (Steig et al, Nature, vol. 457, 2009). Moreover, Lewis’s own paper shows there has been

significant warming in west Antarctica and that the average trend over Antarctica is of warming, not cooling as is often stated.

The reality is that the Antarctic is warming up and is contributing significantly to sea level rise; and that there is strong potential for a greater contribution to sea level rise from Antarctica in the future.

Professor Eric Steig

University of Washington, Seattle, USA

Our 2010  study is now outdated???

Seriously!!  This absolutely is the doctor who never learned about matlab.

For those who have not read the history of the Antarctic wars, here is a pictorial summary.

Steig said this on the cover of Nature magazine:

We said, no you screwed up the math so using the same data it is more like this:  (Ryan O’Donnel)

Because without the satellites the temperature stations alone say this:

So it absolutely cannot be the image on the right:

Steig 09 smeared the peninsula warming across the continent (see how it is missing from the peninsula on the left), but now he says O10 has been “proven” wrong.  This tells me that he has apparently never understood that  the result we produced is nothing more than thermometer data.   That is all it is.

Temperatures as reported by thermometers.  It is a skeptic plot I tell you!!

Perilously, Steig 09 was precociously printed on the previously prestigious primary page of Nature publication.  Carelessly comprised of contaminated and crappy satellite data with thermometers taking a tertiary role in tolling temperature.   Sorrily, Steig’s seminal segment was further stuffed by sloppy math.  (alitteral too far?)

So Jeff , what did he base his conclusion that the PCA distributed thermometers of O10 are now “outdated” and “proven wrong” on?

A single borehole temperature reconstruction at a single point……

One spot

—->     o     <—-

Genius!!

It was workmanship like that which got me labeled as a skeptic in the first place.

Notes to Real Climate and Orsi:

The PCA method S09 attempted to employ, is about redistribution of thermometer information according to covariance of AVHRR satellite data.   By nature, every temperature station affects every point in the reconstruction.  Kriging the temp stations, is a far more controlled and far more verifiable solution for the same thing and it would produce the same result as O10.   The 3 pc’s of the Steig 09 method “smeared” the thermometer data everywhere, so no matter what is published, S09 methods will NEVER be verified.   S09 can never, and will never, be correct….because it isn’t!  The fact that it is to be cited in AR5 is yet another wart on the last few grains of credibility the IPCC holds.

Sorry for that.

Does the error of S09 that mean that O10 is right?    No, of course not.  But O10 is very close to actual thermometer results.  This is because in a “skeptic” plot, we cleverly used actual thermometers.  Bunch of morons I say.  This is in direct contrast to S09 which preferred 3 pc’s of highly noisy Satellite AVHRR data WHEREVER available.  That was not a smart plan ….. Um, if you want good results.

Even with enough pc’s as O10 used, there are points in this sort of reconstruction with noisy data, where modes of the PC are a dominant factor in creating the local trends of the plot.  These methods mean that station information can be and IS copied across an entire continent.  This was proven by the S09 cover of nature(Figure 1 above). The trick is to minimize the information bleeding. What this means to me is that I am quite comfortable that the O10 reconstruction will never be proven wrong, not because something as massive and complex as o10 doesn’t contain a boo-boo, but rather because it is an approximation of a field.  The best anyone will ever do — is improve on it.

Apparently, this is something that Steig has never figured out.  He might not ever work it out, but science is a cold sport and my guess is that those who are smarter than him  ….. will.

===

Other notes of surprise:

What normal thinking person would take a temperature from a lousy borehole and hold that out as superior to an actual thermometer?

???????

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Luther Wu

The sad fact is, Steig and all the other pseudo- scientist shills are the only voices that most people ever hear. Modern truth, as fed to the masses, has reached the pinnacle of Goebbel’s dream.

adolfogiurfa

A peninsula stick! (if mirrored horizontally).

Les Johnson

I hope that Steig checked with Mann, first, because the Orsi paper says that the LIA was a global event.
oops.
From the paper:
This result is consistent with the idea that the LIA was a global event, probably caused by a change in solar and volcanic forcing…

Nylo

Priceless. They definitely need a new way to communicate science to the public lol! Better to shut up than to come with crap like this, they hurt their own “cause” more than skeptics do!

Les Johnson

And figure 3 in the abstract would also indicate a MWP.

Alex

Amen. Why is it that such simple and obvious realities and deceptions are allowed to hang out there as “credible” in a science community? I have watched this for 17 years in plant science (biotechnology and bogus claims of organic farming superiority) and marveled/nauseated at the gall and success of the deceivers.
I’m now convinced that the “journal” model of scientific discourse is/has always been terribly flawed and inadequate (too easy to rig publication and responses) and that the science community should embrace an electronic forum system where vigorous debate and hypothesis testing/proposing can occur real-time and PUBLICLY.
Thanks for being a bit of that and here’s to more of honest, frank, dissection of truth and reality.

When their basic reasoning faculties, never mind their science, are just that bad, what else can you do but have a laugh at it. Amusing piece Jeff.
Pointman

Antarctic ice cover rising, solar magnetic activity falling, any connection?
Some 6 months ago I discovered that the Antarctic’s magnetic field decadal change and the sunspot magnetic activity (from which the TSI is derived), show good correlation
http://www.vukcevic.talktalk.net/TMC.htm
but in percentage terms change is far greater in the case of the earth’s magnetic field (as if there is kind of geomagnetic amplification involved)..
Dr. S. tells me that it must be a coincidence, but I am not entirely happy about that.
Still trying to understand what mechanism can be responsible and what consequences for the Antarctic and S. Hemisphere temperature might be.

Urederra

huh?No mention about the misplaced Harry station? I though It was the main cause of warming.
http://climateaudit.org/2009/02/02/when-harry-met-gill/

Steve Keohane

What normal thinking person would take a temperature from a lousy borehole and hold that out as superior to an actual thermometer?
A PNS ‘scientist’? oh, wait, you specified ‘normal…

KR

“…the same flawed PCA math used by Mann…” – Not really, neither the latest Mann work nor Steig 09 use PCA.
Steig 09 (ftp://soest.hawaii.edu/coastal/Climate%20Articles/Steig_2009%20antarctic%20warming.pdf) uses a regularized expectation maximization (RegEM) method. What it shares with PCA is that it is an iterative refinement method, a gradient descent fitting method, honing in on an answer by reducing error terms at each iteration. But it doesn’t share the math of PCA.
Iterative methods are a well known and characterized method of solving problems that do not have a direct analytic solution. Examples include simulated annealing for the Traveling Salesman problem, Richardson-Lucy deconvolution of astronomic images, and any number of industrial optimization problems. These methods have demonstrated success over and over again.
Regularized EM in particular (http://en.wikipedia.org/wiki/Expectation-maximization_algorithm) attempts to find the best fit of unobserved values given known values (such as in this case coastal temperatures and satellite IR records), given correlation of temperature anomalies and error bars on measurements. In EM you iterate between a set of estimates of your unknowns (which can be random at the start, although I prefer beginning either with uniform values such as “1.0”, or just interpolation of known measures), estimate forward what would be observed, and calculate errors between that and actual observations. You then use those errors to update the estimates of the unknowns. Repeat both steps until the errors converge to somewhere near zero (an asymptotic process, but well below known measurement errors is a good threshold).

It’s always a possibility that someone has incorrectly applied RegEM, or PCA, or other numeric techniques; perhaps their forward computation is incorrect, or their error formulation is wrong – but if you’re going to do that, you have to demonstrate the particular issues with their work. And if you’re going to do that, you need to be talking about the technique(s) they actually used…
REPLY: You are correct, its RegEm. My point is that they sought help from Mann on this paper, and statistical methodology has been shown to be lacking in both MBH98 and Steig 09.
UPDATE: Actually you are not quite correct, but I have made a clarifying update: Note this from Steig et al 2009:

Principal component analysis of the weather station data produces results similar to those of the satellite data analysis, yielding three separable principal components. We therefore used the RegEM algorithm with a cut-off parameter k=3…. A disadvantage of excluding higher-order terms (k>3) is that this fails to fully capture the variance in the Antarctic Peninsula region. We accept this tradeoff because the Peninsula is already the best-observed region of the Antarctic.

Clearly, there was some PCA work done, but RegEm is the main method. The point is that the method produces an erroneous manufactured result, smearing peninsula data over the entire continent, which is not representative of reality. – Anthony

TomRude

Indeed the Orsi et al. 2012 paper says the LIA was a Global Event… Thanks Eric for pointing us to their paper…
BTW in the post, the relation between Steig’s affirmation and the Orsi paper is not clear: in what sense is Orsi’s paper supposed to contradict O’Donnell?

Matt G

Haha, a single borehole temperature reconstruction at a single point is now more accurate than instrumental data. Who would have thought that the scence in climate science couldn’t get any more non science? If this is not an example of who has the biggest agenda then what is?

Latimer Alder

Alex says

the science community should embrace an electronic forum system where vigorous debate and hypothesis testing/proposing can occur real-time and PUBLICLY.

That’s how it all started at, for example, The Royal Society. Lectures and demonstrations were public events with real time debate. Journals only grew up because of the geographical impossibility of shifting people around, And the current model of journal publication assumes that it is paper based and that moving paper around is an expensive and time-consuming operation. Hence the need for the heavily devalued peer-review system and the enormously unwieldy mechanism of paper/counter paper/addendum etc which take months or years to settle questions that could be done in minutes face-to-face.
But the miracle of the internet frees us from nearly all of those geographical and technological limitations. You can have (near) real time public conversations with participants anywhere in the world. This forum is a fine example.
It is not the mechanism that is now the limitation…it is the willingness of the participants to use the new possibilities. And it is reasonable to assume that anybody who shies away from public debate has only a weak case and prefers assertion and table thumping to putting their work under tough scrutiny.
I think we can all identify some (in)famous academic climateers who are reluctant to do so.

“This is something that needs wides circulation” — should be “wider” I think.
[Fixed, thanks. ~dbs, mod.]

vukcevic says:
September 8, 2012 at 8:50 am
Antarctic’s magnetic field decadal change and the sunspot magnetic activity (from which the TSI is derived), show good correlation
The TSI of Lean 2007 does not represent the real variation of the sunspot magnetic activity, so your correlation is spurious.

Yancey Ward

Alex asked:

Why is it that such simple and obvious realities and deceptions are allowed to hang out there as “credible” in a science community?

As a scientist myself, I learned one thing pretty early on in my career that was at odds to the conventional, public perception of science and it’s practioners: that science is a human endeavor, and, as such, is subject to the exact same biases and corruptions that are found in every other human endeavor. There is nothing special about science that makes it less open to corruptors and liars.

If I may suggest
Add large colored dots;
This shows results best
At thermometer spots.
A blue spot on Steig’s
Red field of high heat:
Such contrast intrigues
And shows the deceit.
===|==============/ Keith DeHavelle

Leif Svalgaard says: September 8, 2012 at 9:36 am
The TSI of Lean 2007 does not represent the real variation of the sunspot magnetic activity
Sorry about that, my bad, I have rearranged order, with L. Svalgaard’s TSI reconstruction now at the top, in order to give more accurate and up to date correlation.
http://www.vukcevic.talktalk.net/TMC.htm

Nic Lewis

TomRude wrote:
“in what sense is Orsi’s paper supposed to contradict O’Donnell”.
You might well ask. Steig’s Guardian letter clearly implies that, in his mind, Orsi’s single-borehole surface temperature reconstruction proves that the O’Donnell, Lewis, McIntyre & Connon estimate of overall Antarctic warming is wrong. That a single point proxy temperature reconstruction can prove an multi-meteorological station based estimate for the whole continent wrong seems completely misconceived to me.
BTW, the Orsi reconstruction trend for the 20 years to 2007 is 0.80 deg.C/decade. Satellite AVHRR temperature measurements exist for that period and – although they also are Inaccurate – can be used as a check on Orsi’s trend . Steig’s own cloudmasked AVHRR data (ending one year earlier) shows post 1986 trends of 0.15 and 0.12 deg.C/decade for the two grid cells closest to Orsi’s borehole- a fraction of Orsi’s 0.80 deg.C/decade estimate.

Les Johnson

Some points on Orsi. His Figure 3 shows warming of about 1.5 deg since the 80s. I believe this is what Steig is happy about.
The problem, though, is that Figure 3 shows no warming from 1957 to about about 1980. Steig said there was a warming of about 0.5 deg/decade from 1957 (correct me if the dates are wrong). That would make warming of about 2.6 deg warming to 2009 (2.15 deg to 2000). Not the 1.5 deg measured by Orsi to 2000. Orsi’s start date is moot, as he shows no warming 1900-1980.
Thus, Orsi validates O’donnel 2010 (O10), as O10 shows about 0.25 deg/decade of warming from 1957, in the location of the WAIS Divide. (yellow, 0.25 deg/decade, in the temperature scale for O10; red and 0.5 deg/decade for Steig09). O10 would give a warming of 0.25 deg/decade, vs Orsi’s 0.35, starting both from 1957.
This is also totaly ignores the fact that Orsi shows no warming for over 20 years (1957-1980), but which Steig09 says did occur.
Steig09 is actually proven wrong by the Orsi paper.Both in the amount of warming, and in the length of the warming, and in the slope of the warming. Orsi’s numbers are much closer to O10, except the slope.
Granted, Orsi’s warming is about 0.75 deg/decade, but there is only two decades of warming in his record.
Summary: From 1957, O10 shows 1.075 deg of warming to 2000. Steig09 shows 2.15 deg. Orsi’s measured warming from 1957 is 1.5 deg to 2000. O10 (-28% low) is closer to Orsi than Steig (+43% high).
caveat: most of the numbers I use are eyeballed, albeit using a ruler for Orsi and figure 3.

Craig Moore

Instead of this —-> o <—-, perhaps it should be this )*(

Gary Pearse

“What normal thinking person would take a temperature from a lousy borehole and hold that out as superior to an actual thermometer?”
A post normal person?
Yancey Ward says:
September 8, 2012 at 9:42 am
“There is nothing special about science that makes it less open to corruptors and liars.”
I have suggested that scientists must be disciplined by a professional association that can discipline or bar its members from practicing in extreme cases of incompetence and abuse. It works for engineers who have to be on their toes when they build a bridge or a space shuttle or just about everything that isn’t built by nature. Non sequitur: there is no such thing as a rocket scientist – only an engineer does this kind of work.

There are greater temperature fluctuations at the higher latitudes. Thus, the equator is much more stable than the poles. So we would expect polar temperatures to vary [as they are doing now, especially in the Arctic].
But globally there is very little change. This is what the alarmist crowd is running around in circles and hand-wringing about. As any rational person can see, runaway global warming is trumped up nonsense. And Steig is riding the gravy train by falsifying reality. Shame on hiim.

gringojay

Bore hole verses READER (Reference Antarctic Data for Environmental Research) …:
READER data (as of 2005) from 11 sites showed warming & 7 sites showed cooling,
verses Bore hole from 1 site showed warming & warmer yellow snow nearby.

I am certain that Dr. Steig is (or maybe not) aware of something called ‘polar amplification’ whereby surface temperature in the polar areas varies to much larger extent than at lower latitudes.
http://www.vukcevic.talktalk.net/PA.htm
Polar amplification makes temperature within polar areas less stable not only from point to point geographically but also in time.

Don Keiller

Tell me again, just how did Steig obtain his doctorate?
Did he buy it from some dodgy, one room college?
Can’t see any other option, because he certainly doesn’t do maths or science very well.

TomRude

@ Nic Lewis, thank you for your time and clear answer.

Peter Foster

Some time back there was a posting on WUWT about a type of thermometer being installed widely across the Antarctic peninsula that allowed reflected radiation to hit the sensor causing readings up to 10°C above the actual temp..
Has the record ever been corrected for this or do the temperature analyses of the peninsula still use this faulty data ?

Oscar Bajner

Over at Bishop Hill I read of the CookBook club of the month who regard themselves as Spartans holding back the WUWTatian “hordes”.
When the next Climate Change movie comes out I suggest they use Nelson, not Leonidas, as the template:
One tree,
One borehole,
One trick
Theme music by Whitney: Didn’t we almost have it all”

Leif Svalgaard says: September 8, 2012 at 9:13 am
There is a certain entertainment value in your stuff
Perhaps Ms Dickey from JPL and I should team up and form an entertainment duo perhaps on lines the ‘Hansen-Mann’ troupe.
Jean Dickey of NASA’s Jet Propulsion Laboratory, Pasadena:
Other possibilities are that some other Earth’s core process (where Earth’s magnetic field originates) could be having a more indirect effect on climate, or that an external (e.g. solar) process affects the core and climate simultaneously.
http://www.vukcevic.talktalk.net/TMC.htm

Dr Burns

Sounds like arguing whether my house is warming or cooling when the temperatures of the oven, hotplates and refrigerator are included.

vukcevic says:
September 8, 2012 at 2:16 pm
that an external (e.g. solar) process affects the core and climate
Just shows how little Dickey understands of this.
But that hardly matters when the correlation is spurious to begin with. As I said many a time, a spurious correlation does not need explanation or closer examination [except perhaps of the proposer’s head].

jim

But since we know from everywhere and everything else that GLOBAL WARMING IS REAL, then S09 must be right! We KNOW IT FROM EVERYTHING ELSE SO IT’S RIGHT!
GLOBAL WARMING IS REAL! IT MUST BE RIGHT!!!! MUST…MUST…BE…RIGHT!!
WARMING REAL! MUST BE RIGHT! WARMING REAL! MUST BE RIGHT! MUSSSTTT BEEE RIGHHTTTTTTTTTTT!!!!
sarc

Bill Illis

The Borehole Temperature reconstruction method is seriously flawed in some manner.
Just compare the Borehole temperature reconstruction method for Greenland versus the published Antarctica Epica Dome C temperatures from the dO18 isotopes.
Greenland got to -25.0C in the ice ages versus -10.0C in Antarctica while polar amplification (2X the global climate change) should work very similar in both places.
Greenland got to +8.0C 123,000 years ago in the Borehole method while Antarctica was only +1.0C. [At +8.0C, the glaciers should have completely melted out in Greenland, especially considering the fact that 128,000 years ago was even warmer – the Greenland isotopes don’t go back far enough to hit what was the peak temperature period in the Eemian interglacial at 128,000 years ago – who knows what the borehole method would have produced; +13.0C or so].
The methodology is just not sound.
http://s14.postimage.org/wxf5d348h/Greenland_Borehole_vs_Antarctica.png

richcar 1225

Antarctica is currently one giant anti cyclone on steroids. The SAM index is near a record high meaning the interior plateau is at record cold and high pressure compared to the sub tropics resulting in Katabatic westerly winds (coriolis efffect) roaring around the continent dragging the circumpolar current with it resulting in record upwelling at the Polar front which is resulting in the coldest Southern ocean since 1980. Of course Steig amazingly blames this on the ozone hole that should have disapeared by now due to the Montreal protocol. The Antarctic Pennisula warming is simply due to Katabatic downsloping winds not ocean SST. I believe there is likely a solar connection between the ozone hole and the strength of the anti cyclonic winds.
Southern Ocean SST:
http://bobtisdale.files.wordpress.com/2012/08/13-southern.png

pat

The fact that these ‘scientists’ simply refuse to report that Antarctica is cooling, and has been for decades, with the exception of the Peninsula is simply disgusting. They have turned climatology into phrenology.

Brian H

When in a deep borehole with the sides collapsing, stop digging. Or drilling.

Ninderthana

Some people [e.g. Leif] are blind to what they don’t know because of all the knowledge that they do know.

“…We therefore used the RegEM algorithm with a cut-off parameter k=3…A disadvantage of excluding higher-order terms (k>3) is that this fails to fully capture the variance in the Antarctic Peninsula region. We accept this tradeoff because the Peninsula is already the best-observed region of the Antarctic…”
First off, I’ll agree that “the Peninsula is already the best-observed region of the Antarctic”, because we’ve now seen Steig et al (2009), O’Donnel et al 2010 and Orsi et al (2012) – and I’m sure that we’ll see a rebuttal to the Orsi paper, too.
But it’s that first part that makes me wonder – if choice of the parameters is so critical (going from k=3 to k=>3) that use of higher-order terms fails to fully capture the variance in the Antarctic Peninsula, then how strong was the variance?
It sounds like they used the lowest cut-off they could that still showed the Peninsula region’s warming – not really caring how the rest of the CONTINENT fared.
I hope somebody can replicate this study. I’d really love to see the “maps” with different parameters plugged in (for example, what’s the difference between k=3 and k=3.1).

richcar 1225

This is the current reality of cold in Antarctica that is as much as 10 degrees C below the 1998-2006 average.
http://www.climate4you.com/images/ANTARCTIC%20Temp%20201207%20versus%201998-2006%201200km.gif
Where are the headlines about this.

jorgekafkazar

richcar 1225 says: “…The Antarctic Pennisula warming is simply due to Katabatic downsloping winds not ocean SST.”
Isn’t there significant volcanic activity in and around the peninsula?

geo

Oy. Any port in a storm for Steig, eh? Accept the LIA was global and probably volcanic or solar. . . except that also means the temp rise was significantly impacted by rebound from natural variation, and so not so terribly interesting as proof of AGW, particulary future extrapolation of AGW. How. . . .unprincipled.

Rob Dekker

Bill Illis said :

Greenland got to -25.0C in the ice ages versus -10.0C in Antarctica while polar amplification (2X the global climate change) should work very similar in both places.

Where did you get that idea from ? Why should the Arctic and the Antarctic show the same polar amplification, Bill ?

Rob Dekker

I’m sorry if I missed the hoopla.
Did O’Donnell et al conclude that Antarctica is cooling ?

Rob Dekker

Jeff Condon wrote (in the original post) :

Unfortunately for us, the article itself has been updated in response so we can’t read the original.

Sorry, Jeff, but your are confusing the Antarctic for the Arctic.
The post with the letter from Eric is still where it has been since it was posted :
http://www.guardian.co.uk/environment/2012/sep/06/antarctic-warming-sea-levels?newsfeed=true

Rob Dekker:
At September 9, 2012 at 1:13 am you ask Bill Illis:

Why should the Arctic and the Antarctic show the same polar amplification, Bill ?

I cannot answer for Bill Illis, but I know where I got it from: it was the UN Intergovernmental Panel on Climate Change (IPCC) Working Group 1 (WG1: i.e. the “science”).
The IPCC First and Second Assessment Reports provided plots of climate model ‘projections’ which showed it. And no IPCC report has said otherwise since.
Richard

DirkH

Rob Dekker says:
September 9, 2012 at 2:32 am

“Sorry, Jeff, but your are confusing the Antarctic for the Arctic.
The post with the letter from Eric is still where it has been since it was posted :”

Reading comprehension, Rob. The article by John Vidal to which Nic Lewis responded has been updated, not Steigs letter.

“Eric Steig has written a letter to “The Guardian” (booming voice) in response to a Nic Lewis letter patiently explaining problems in an article written by yet-another-know-nothing with a keyboard. Unfortunately for us, the article itself has been updated in response so we can’t read the original. “

DirkH

And of course there is STILL pretty funny stuff in the Grauniad article.

“North Pole webcam picture taken on 22 August 2012 showing ice cap melting. Climate scientists expect the Arctic sea ice is on course to plummet to its lowest levels ever this weekend.”

In other words, Climate scientists expect the Arctic is on course to become ice-free this weekend. says the Grauniad. As that is the lowest historical level of arctic sea ice; zero.

“Dr Burns says:
September 8, 2012 at 2:18 pm
Sounds like arguing whether my house is warming or cooling when the temperatures of the oven, hotplates and refrigerator are included.”
Yes, that is exactly right. Now try and establish the average temperature of your house, including all of the above, relying on thermometers placed near the oven, and establish the historic averages by taking a single core from a wooden door in the basement to come up with a proxy.
Show that the proxy was about -20 deg 50 years ago, ignoring common sense, and that the current temperatures are about +20 deg, extrapolate exponentially 100 years into the future, and announce to your family that you should be able to cook dinners 5 years from now using ambient temperature inside your house, which by then be hot enough to melt steel…