Hockey stick observed in NOAA ice core data

At the Foresight Institute, J. Storrs Hall had some interesting graphs made from NOAA ice core data (Alley, R.B. 2000. The Younger Dryas cold interval as viewed from central Greenland. Quaternary Science Reviews 19:213-226.) It sure seems to mirror other hockey sticks this past century. Dr. Mann will be thrilled to see this I’m sure.

J. Storrs Hall writes:

One thing that Climategate does is give us an opportunity to step back from the details of the AGW argument and say, maybe these are heat-of-the-moment stuff, and in the long run will look as silly as the Durants’ allergy to Eisenhower. And perhaps, if we can put climate arguments in perspective, it will allow us to put the much smaller nano arguments (pun intended) into perspective too.

So let’s look at some ice.

I’m looking at the temperature record as read from this central Greenland ice core. It gives us about as close as we can come to a direct, experimental measurement of temperature at that one spot for the past 50,000 years.  As far as I know, the data are not adjusted according to any fancy computer climate model or anything else like that.

So what does it tell us about, say, the past 500 years? (the youngest datum is age=0.0951409 (thousand years before present) — perhaps younger snow doesn’t work so well?):


Well, whaddaya know — a hockey stick.  In fact, the “blade” continues up in the 20th century at least another half a degree.  But how long is the handle? How unprecedented is the current warming trend?


Yes, Virginia, there was a Medieval Warm Period, in central Greenland at any rate.  But we knew that — that’s when the Vikings were naming it Greenland, after all.  And the following Little Ice Age is what killed them off, and caused widespread crop failures (and the consequent burning of witches) across Europe.  But was the MWP itself unusual?


Well, no — over the period of recorded history, the average temperature was about equal to the height of the MWP.  Rises not only as high, but as rapid, as the current hockey stick blade have been the rule, not the exception.


In fact for the entire Holocene — the period over which, by some odd coincidence, humanity developed agriculture and civilization — the temperature has been higher than now, and the trend over the past 4000 years is a marked decline.  From this perspective, it’s the LIA that was unusual, and the current warming trend simply represents a return to the mean.  If it lasts.


From the perspective of the Holocene as a whole, our current hockeystick is beginning to look pretty dinky. By far the possibility I would worry about, if I were the worrying sort, would be the return to an ice age — since interglacials, over the past half million years or so, have tended to last only 10,000 years or so.  And Ice ages are not conducive to agriculture.


… and ice ages have a better claim on being the natural state of Earth’s climate than interglacials.  This next graph, for the longest period, we have to go to an Antarctic core (Vostok):


In other words, we’re pretty lucky to be here during this rare, warm period in climate history.  But the broader lesson is, climate doesn’t stand still.  It doesn’t even stay on the relatively constrained range of the last 10,000 years for more than about 10,000 years at a time.

Does this mean that CO2 isn’t a greenhouse gas? No.

Does it mean that it isn’t warming? No.

Does it mean that we shouldn’t develop clean, efficient technology that gets its energy elsewhere than burning fossil fuels?  Of course not.  We should do all those things for many reasons — but there’s plenty of time to do them the right way, by developing nanotech.  (There’s plenty of money, too, but it’s all going to climate science at the moment. :-) ) And that will be a very good thing to have done if we do fall back into an ice age, believe me.

For climate science it means that the Hockey Team climatologists’ insistence that human-emitted CO2 is the only thing that could account for the recent warming trend is probably poppycock.

h/t to Kate at SDA


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poppycock sums it up perfectly!

Great post –
Which pre-industrial temperature we have to stay within 2 degrees of…

David Y

But do any of these cores indicate who will take the next Stanley Cup? 😉
Great piece–and invaluable perspective. Thanks!

Bobby W

Wow! It pays to put things in perspective. Great piece. Thanks.

Brian D

Pick your cherry. And we all know who’ll pick what.

Alan Wilkinson

So the ice core data says Greenland can get a heck of a lot hotter before all its ice will melt – in fact, 30 deg C hotter.


On the very last graph (at the bottom), there is a ‘ringing’ that is not seen on the other peaks. Could this be a sign of human influence?


Bob Carter has also shown this. It’s all a matter of choosing the starting point. Great work.
Will this be shown in the media? Of course, and especially on the ABC…. Then again, maybe not.
The delegates in Copenhagen are doing their best to tie themselves in knots. Give them enough rope… Time will tell, but we’ll all be broke by then.

In this instance, it looks like the helicopter-view trashes that from Big Al’s private jet.

Robert of Ottawa

Brilliant presentation. Sucks you in at the beginning, then reeals surprise after surprize.

Erik Anderson

I’d also love to see an expanded diagram of the Antarctic core data (Vostock) between 800 CE and the present (à la fig. 2). Is the MWP detectable there as well?

This is great stuff, stuff you won’t see on CNN with Campbell Brown. BTW Gavin was on Roberts’ show today too, I thought at the time, ya know, having Gavin, or Mann, or Hansen on these shows running interference for… themselves… is kinda like having John Gotti testifying before a House Subcommittee on Organized Crime as an expert witness and telling them “there is no such thing as the Mafia.”

Robert of Ottawa

David Y (16:46:16) :
But do any of these cores indicate who will take the next Stanley Cup?
Yes, they do. Just look at the last graph. It is the emphasis of Ottawa Senators. Just try it; it’s true! ‘TTaWA SeNaTor


So the previous four interglacial periods were by 2 -3 deg C warmer than now. I strongly wonder whether “runaway global warmings” occurred then. Anybody please teach me.
In any event the seven consecutive graphs will make a good fodder for my lecture on environment science in the coming semester. Many thanks.

If you assume that MWP is the high and LIA is the low of a 1100 year cycle, our present warming fits nicely on the upswing from the LIA. Try fitting the data to sine(2*PI*year/1100+1.81). This would indicate that we can have natural warming into the next century and enjoy a modern warming period that is not quite as warm as MWP ( much longer term trend is getting colder).

Akira Shirakawa

A problem with these charts that warmers could point to is that the temperature record stops at about year 1900, not showing the supposedly “unprecedentedly warm” recent temperatures.


OT: Gavin vs John Christy debate on CNN’s Situation Room an hour ago:


Any recent ice cores (after 1990) so we can see what happens next?


Simply outsatnding.
Thank you guys!

Dr. Ross Taylor

Thank you for this excellent piece of realism.
Sigh…Al Gore, on CNN yesterday, pronounced to the world that humans were responsible for the majority of CO2 in the atmosphere. Of course, no-one picked up on it. I could not believe what I was hearing:
“CHETRY: And that goes along with what David in Arizona asked you. He wants to know, please tell us what percentage of carbon dioxide is caused by human activity relative to other sources of carbon dioxide.
GORE: Well, the majority of it is caused by human activity…”
Sigh, Al, Al, Al, surely even you know that humans contribute only 3.225% of CO2, whereas 96.775% is entirely natural. Since when is 3% a majority?
I really do prefer to think that you are a bit dim or mistaken than what others accuse you of, but I am beginning to wonder.
Update on non-warming in Copenhagen: As emergency Global warming conference continues, it is perhaps ironic to study some weather information readily available on the internet. I apologize that the figures are not absolutely precise because they are taken from graphs at Anyone can check my calculations, which took about 20 minutes and were not taxpayer funded. In the last 28 years (as far as the online records go back), the highest temperature in Copenhagen in December was 11 degrees C and that was back in 1983. Over these years, the average highest December temperature was around 7 C.
First day of Copenhagen: surprise surprise,a high of 7 C, exactly the same as the average of the last 28 years and 4 degrees COOLER than the high of the last 28 years.
Second day: a high of 7 C, the same.
Third day: a high of 6 C, 5 degrees cooler than the December high of the last 28 years.
Can we please have a reality check. Perhaps the eminent delegates are not aware?


Cherry picking, some may say
Is pleasant work and fine,
But murky moil and toil it is
When you’re hiding the decline.
No playful breeze will cool your brow,
No sunlight strike your face,
As you pluck your strange, outlier fruit
In the depths of cyberspace.
Track well your codes and protocols
As through this grove you rove,
Lest you be called to replicate
The tangled web you wove.
Oh, it’s “‘Arry this” and “‘Arry that,”
And “‘Arry, keep t’yer ‘ole,”
But “Save us, ‘Arry, save us!”
When ‘eds begin to roll.


Mark (16:57:14) :

On the very last graph (at the bottom), there is a ‘ringing’ that is not seen on the other peaks. Could this be a sign of human influence?

Resolution decreases the further back in time you go.


Wow! This graph shows all the climate events discussed by Paleoclimatologists like Bryson and Lamb including the sharp cooling 8,200 ybp, the bifurcated Holocene Optimum and the cooling that preceded the drying of the Sahara and the rise of Egypt.
Of course at that high a latitude, it has to be interpreted in light of the higher degree of tilt of the Earth’s axis which in the early Holocene would mean a higher sun angle for the North. I’ve read a lot comments about the interglacials lasting only about 10,000 years but detailed studies of the Ice Ages in Britain (Homo Britanicus)show that the last time the Milankovich signal was similar to the present, the corresponding interglacial in the British Isles was 40,000 years with a sharp cooling in the middle. Clearly a lot more work needs to be done on the drivers of our climate to come up with knowledge that has real predictive power.


…and now a leading “economist” has to say something, afraid he will lose money, or credibility is he?

Stern: Confused climate skeptics
A leading British climate change economist warned Tuesday that those who doubt the science of global warming are confused — and said their skepticism should not derail efforts to strike a climate deal in Denmark.


Great post – nothing punctures the AGW balloon like the perspective afforded by deep history. I just have one (I hope not too stupid) question: what is measured on the vertical axes?

George E. Smith

“”” Does it mean that we shouldn’t develop clean, efficient technology that gets its energy elsewhere than burning fossil fuels? Of course not. We should do all those things for many reasons — but there’s plenty of time to do them the right way, by developing nanotech. (There’s plenty of money, too, but it’s all going to climate science at the moment. ) And that will be a very good thing to have done if we do fall back into an ice age, believe me. “””
Well the ice capades are rather nice; thanks for that. But as to the statement above.
What on earth leads you to believe that nanotechnology has any application to future energy sources ?
I have plenty of nanotechnology right now; use it every time I go fishing, as a matter of fact. My fishing rods use nanotechnology which goes inside a secret coating (called “Pixie Dust”) that is ued in the manufacture of the Carbon fiber (best place to sequester excess carbon). The nanotech pixie dust helps the epoxy material to bond to the carbon fibers more tenaciously, which stops the whole thing from peeling apart.
But I can assure you that it doesn’t put out any energy, except that which I put in in the form of my casting stroke (they are fly rods).
Why do people jump on to buzzwords as if they are the cure for whatever ails you.
If we don’t have Fetal Stem cells to cure everything from gout to ignorance and stupidity; we have to have nanotechnology to cause the taxpayer to dig deeper into his pockets to come up with grant money for otherwise out of work so-called scientists.
We’ll be using fossil fuels into the forseeable future; with just niche applications for anything else. It is not as if we haven’t looked pretty thoroughly for other ways to do things.
Stored chemical energy obtained by the oxidation of carbon and hydrogen, will be our main source of energy long after this climate change insanity is rotting on the trash heap of history.
If you think nanotechnology is the answer to our problems; why don’t you sell your house and invest the money in nanotechnology; but do it soon before the deepening cold won’t let you sell your house.


Not being a “climate scientist”, exactly how do you extract temperatures from an ice core ?


Notice how we have been in a general cooling trend since about 1500 BC. Each warming period has peaked at a lower temperature than the one before it. The trend since 0 AD has been particularly dramatic.
We might already BE in the next ice age and it might have begun at around 0 AD.


Looking at the longer trend, it seems to me that we may be on the trailing edge of this warm period!
Damn! I hope not! I’ve got a few years left in me yet & we don’t have the technology to cope with another LIA!


Well, why can’t our “brilliant” astrophysicists (arrogant) link this to the Sun???
Not Sunspots, but the Sun’s actual output and conversion to heat on the Earth!!
They can’t predict anything correctly!! Look at the Sunspot predictions for Cycle 24!! Since when is science based on a consensus?? Is the Earth still flat??
Either the Sun’s model is completely broken, or the Sun’s galactic position must affect energy reaching the Earth.
How can any “respectable” (cowardly) person with a degree not know that climate comes from the Sun????
During an eclipse, the temperature in the tropics drops 20 degrees F in 15 minutes. How can a rational person not know that the Sun controls our climate?? Sunspots are discussed, but not the real issue -> energy from the Sun that affects the Earth.
Will the real scientists come forward, not these jokers!!!!!

Robert Austin

Small point. Should not “the youngest datum is age=0.0951409 (thousand years before present)” actually say 100 yrs before present? (actually 95 years). Otherwise, a sweet presentation that is easy to lay on the true believers around me.

Perspective !!!
Great details !!
But I can only guess that it will fall on deaf ears.


I would love to see CO2 plotted on top of the second graph with the MWP so that my simple brain could see the correlation.


Ooops – just remembered – this is Greenland so of course the temps are below zero – my bad.

What about the lagging CO2 levels? What are the theories for that?

Great website by-the-way!

John N

Wonderful post! I enjoyed reading step…by step…by step.


John Christy did superbly on the Situation Room with Wolf Blitzer: Clear, succinct and supremely confident. Gavin nattered away like a teenager caught doing something wrong. He made mistakes in not saying exactly what hide the decline consisted of. John Christy nailed it. It had to give Wolf Blitzer, who is not dumb, something to think about.


Just an FYI:
“Alley, R. B.” is Dr. Richard Alley, who is in the Department of Geosciences at Penn State and associated with the Earth System Science Center. Yes, the same ESSC that Dr. Mann is Director of.

Chris Edwards

I am not a scientist but I was taught about the Vikings in school (real school, a grammar school!) and have read articles in NG about how the farms and fields are starting to appear from under the ice. That tells me all the graphs do, that we can get warmer too and flourish, A Gore was not tearing about the planet in jets but it was hotter, the variance tells me that weather is unpredictable and what should we call people who claim to predict the unpredictable? then what should we name them if they also claim to be scientists? Also there is an article in an early National Geographic centering on a lagoon, I think in Alaska, that had 5 glaciers joining and exiting the lagoon to calf icebergs in the ocean, 20 years later there were 5 distinct glaciers now melted back, calving into the lagoon. This shows considerable melting back, they were also victorian explorers who wrote the articles in the 1800s. I am frightened (politically) where this is going, I left England and have moved to Canada (good move in an ice age!) as the gov there interfere with your life all the time, they are control freaks operating through health and safety, EPA and CSA covers, this is now coming fast to the USA. If it was not for blogs like this and good scientists and sane folk here I would have worried about my own sanity! thanks.

I have been waiting for this kind of data. I will plot it against the Holocene solar proxy records (14C & 10Be) and see what transpires.


George E. Smith (17:33:45) :
George, it was my understanding that fetal stem cells were not nearly as effective for cures as adult stem cells. Is this incorrect?

Carl in NC

George: For a discussion of nanotech, go to
Making better fishing rods is not the only thing it is used for.


Yes, what about CO2. That’s the final argument of warmists.
Do ice core data suggest as NASA points that is in its highest concentration for 400.000 years????


I like poppycock, too.
Just a cursory look, but that seems to square well with:
does it not?

Skeptic Tank

Alan Wilkinson (16:53:53) :
So the ice core data says Greenland can get a heck of a lot hotter before all its ice will melt – in fact, 30 deg C hotter.

Uh, from the second plot, I see the MWP being about 2.5°C above the Little Ice Age.

akira said “A problem with these charts that warmers could point to is that the temperature record stops at about year 1900”
actually, the fourth graph seems to go to 2000.

Bill Illis

These temperature numbers have twice as much variation as other estimates.
The researcher who prepared these numbers is Richard Alley who works under Michael Mann.
His purpose in increasing the temperatures estimates was to exaggerate the effect of the Younger Dryas event and provide further scare-factor to global warming.
The Antarctic Ice Core temperature (above) only shows a 2.0C decline during the Younger Dryas but Greenland’s (above) are 15.0C. Greenland did experience more of a decline than Antarctica in this event but nowhere near these numbers.
During the ice ages, Antarctica declines by 10.0C yet Greenland declines by more than 20.0C?
Take the numbers and divide by half.


“”Does it mean that it isn’t warming? No.””
Well that certainly depends on your definition of “warming.”
I think a better answer is, “that depends on the time period under consideration.”


It was much warmer during the medieval warming period.
There are Vikings buried in permafrost in Greenland.
The permafrost is not disturbed.
It was not frozen when they were buried.
I would call that warmer then today, a lot warmer.
The ironic thing is that that this evidence of the medieval warming period is in a museum in Copenhagen.
The Fate of Greenland’s Vikings February 28, 2000 by Dale Mackenzie Brown
Also, the medieval warming period was global.
Fraudulent hockey sticks and hidden data
For a satirical look at the climategate computer programming (hiding the decline):
Anthropogenic Global Warming Virus Alert.