Another hockey stick – this one billed as 'scarier' than Mann's

I had to chuckle at the cacophony of Twitfests going on today over this new study from Marcott et al. I especially liked the Mother Jones headline being Tweeted: “The Scariest Climate Change Graph Just Got Scarier”.

It rather reminds me of some people being fearful of certain religious icons.

marcott-A-1000[1]

Yes, be afraid, very afraid, of that “unprecedented” (there’s that word again in the abstract) 0.7C temperature rise is the message I suppose. While the MSM will trumpet this I’m sure, we’ll get down to finding out just how good the science is. One potential problem is that the pollen data median sampling of 120 years, which is 4x the 30 year climate normals periods used today. That’s pretty low resolution for a study that is focusing on 2000 years and leaves lots of opportunity to miss data. Further, when they say the last 100 years was the warmest (with higher resolution data) they really aren’t comparing similar data sets when the other data has a 120 year median sampling.

Here’s the press release:

Press Release 13-037

Earth Is Warmer Today Than During 70 to 80 Percent of the Past 11,300 Years

Reconstruction of Earth history shows significance of temperature rise

March 7, 2013

With data from 73 ice and sediment core monitoring sites around the world, scientists have reconstructed Earth’s temperature history back to the end of the last Ice Age.

The analysis reveals that the planet today is warmer than it’s been during 70 to 80 percent of the last 11,300 years.

Results of the study, by researchers at Oregon State University (OSU) and Harvard University, are published this week in a paper in the journal Science.

Lead paper author Shaun Marcott of OSU says that previous research on past global temperature change has largely focused on the last 2,000 years.

Extending the reconstruction of global temperatures back to the end of the last Ice Age puts today’s climate into a larger context.

“We already knew that on a global scale, Earth is warmer today than it was over much of the past 2,000 years,” Marcott says. “Now we know that it is warmer than most of the past 11,300 years.”

“The last century stands out as the anomaly in this record of global temperature since the end of the last ice age,” says Candace Major, program director in the National Science Foundation’s (NSF) Division of Ocean Sciences. The research was funded by the Paleoclimate Program in NSF’s Division of Atmospheric and Geospace Sciences.

“This research shows that we’ve experienced almost the same range of temperature change since the beginning of the industrial revolution,” says Major, “as over the previous 11,000 years of Earth history–but this change happened a lot more quickly.”

Of concern are projections of global temperature for the year 2100, when climate models evaluated by the Intergovernmental Panel on Climate Change show that temperatures will exceed the warmest temperatures during the 11,300-year period known as the Holocene under all plausible greenhouse gas emission scenarios.

Peter Clark, an OSU paleoclimatologist and co-author of the Science paper, says that many previous temperature reconstructions were regional and not placed in a global context.

“When you just look at one part of the world, temperature history can be affected by regional climate processes like El Niño or monsoon variations,” says Clark.

“But when you combine data from sites around the world, you can average out those regional anomalies and get a clear sense of the Earth’s global temperature history.”

What that history shows, the researchers say, is that during the last 5,000 years, the Earth on average cooled about 1.3 degrees Fahrenheit–until the last 100 years, when it warmed about 1.3 degrees F.

The largest changes were in the Northern Hemisphere, where there are more land masses and larger human populations than in the Southern Hemisphere.

Climate models project that global temperature will rise another 2.0 to 11.5 degrees F by the end of this century, largely dependent on the magnitude of carbon emissions.

“What is most troubling,” Clark says, “is that this warming will be significantly greater than at any time during the past 11,300 years.”

Marcott says that one of the natural factors affecting global temperatures during the last 11,300 years is a gradual change in the distribution of solar insolation linked with Earth’s position relative to the sun.

“During the warmest period of the Holocene, the Earth was positioned such that Northern Hemisphere summers warmed more,” Marcott says.

“As the Earth’s orientation changed, Northern Hemisphere summers became cooler, and we should now be near the bottom of this long-term cooling trend–but obviously, we’re not.”

The research team, which included Jeremy Shakun of Harvard and Alan Mix of OSU, primarily used fossils from ocean sediment cores and terrestrial archives to reconstruct the temperature history.

The chemical and physical characteristics of the fossils–including the species as well as their chemical composition and isotopic ratios–provide reliable proxy records for past temperatures by calibrating them to modern temperature records.

Analyses of data from the 73 sites allow a global picture of the Earth’s history and provide a new context for climate change analysis.

“The Earth’s climate is complex and responds to multiple forcings, including carbon dioxide and solar insolation,” Marcott says.

“Both changed very slowly over the past 11,000 years. But in the last 100 years, the increase in carbon dioxide through increased emissions from human activities has been significant.

“It’s the only variable that can best explain the rapid increase in global temperatures.”

-NSF-

A Reconstruction of Regional and Global Temperature for the Past 11,300 Years

Shaun A. Marcott1, Jeremy D. Shakun2, Peter U. Clark1, Alan C. Mix1Author Affiliations


  1. 1College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.

  2. 2Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
  1. *To whom correspondence should be addressed. E-mail: marcotts@science.oregonstate.edu

Abstract

Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.

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

UPDATE: Andrew Revkin emailed me a link to his piece where the issue is commented on by Mann and Robert Rhode of (BEST). Being a cheerleader, Mann has little useful to add, but Rhode has some useful comments:

The Marcott et al. results may refine our understanding the last 10,000 years; however, the broad picture of Holocene climate does not seem to have been significantly changed by their findings. Previous work had already pointed towards a period of early Holocene warmth somewhat higher than recent centuries.

In discussing their result, there is one important limitation that I feel deserves more attention. They rely on proxy data that is widely spaced in time (median sampling interval 120 years) and in many cases may also be subject to significant dating uncertainty. These effects will both tend to blur and obscure high frequency variability. They estimate (page 1, column 3) that only 50% of the variance is preserved at 1,000-year periods. This amount of variance suppression is roughly what you would expect if the underlying annual temperature time series had been smoothed with a 400-year moving average. In essence, their reconstruction appears to tell us about past changes in climate with a resolution of about 400 years. That is more than adequate for gathering insights about millennial scale changes during the last 10,000 years, but it will completely obscure any rapid fluctuations having durations less than a few hundred years. The only time such obscuring might not occur is during the very recent period when dating uncertainty is likely to be low and sample spacing may be very tight.

Because the analysis method and sparse data used in this study will tend to blur out most century-scale changes, we can’t use the analysis of Marcott et al. to draw any firm conclusions about how unique the rapid changes of the twentieth century are compared to the previous 10,000 years. The 20th century may have had uniquely rapid warming, but we would need higher resolution data to draw that conclusion with any certainty. Similarly, one should be careful in comparing recent decades to early parts of their reconstruction, as one can easily fall into the trap of comparing a single year or decade to what is essentially an average of centuries. To their credit Marcott et al. do recognize and address the issue of suppressed high frequency variability at a number of places in their paper.

Ultimately, the Marcott et al. paper is an interesting addition to the study of millennial scale climate variability during the Holocene. Their results are broadly consistent with previous findings, but the details are interesting and likely to be useful in future studies. However, since their methodology suppresses most of the high frequency variability, one needs to be cautious when making comparisons between their reconstruction and relatively rapid events like the global warming of the last century.

Revkin has a video interview with co-author Shakun also, see it here:

http://dotearth.blogs.nytimes.com/2013/03/07/scientists-find-an-abrupt-warm-jog-after-a-very-long-cooling/

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Richard

let me get this right, over the last 2000 years, the 100 -150 year droughts happened when the co2 levels were lower.

DesertYote

OSU, well that says it all.

GlynnMhor

Why does Mann’s reconstruction extend a century into the future, according to the chart?
And why does it not align with the new effort?
And why are we not seeing how the proxies tie to the instrumental records?

Richard

droughts in the US.

M Courtney

If the paper is correct and the world was cold until the industrial revolution then it’s hard to argue that global warming is a bad thing.
The paper shows an uptick in temperature at exactly the point that lifespans increase, infant mortality decreases and we all got more capable of surviving disasters.

sophocles

they say “warmer than 70-80% of the previous 10,000 years” so the obvious question is:
What happened during the missing 20-30%?
Would those just happen to be the Holocene Optimum, the Minoan Warming, the Roman Warming and the Medieval Warming and all the other unprecedented warmings we haven’t named?
And how much warmer were they, to be so carefully omitted?

Eric H.

Here is my take away: The current temps are not as high as past interglacials. The warming trend of the past 100 years is not duplicated in the paleo record. The rest of the press release is the normal propoganda. Warmer than 70% of the previous record? Spin baby spin!

A drought of science and intelligence.

Martin

I’m with you, Anthony, no point in acting scared. One question though. How long did it take to warm up the first time 10,000 years ago compared to how long it’s taken to warm back up now? Looks a steep rise. When will the temperature flatten out again? Not that I’ll be around anyway lol.

George McFly

I’m going to go shopping later today for some flowery tropical shirts…..

I predict more and more nonsense of this sort, right up to the moment it starts costing governments money. Interesting to note how quickly major, independent, news organisations are getting out of the climate reporting business…

There’s nothing wrong with the climate, and CO2 has nothing to do with it: http://www.youtube.com/watch?v=WK_WyvfcJyg&info=GGWarmingSwindle_CO2Lag
Ok, why do I say that? First, there’s no hockey stick. To create the h stick the MWP was squashed, the LIA was ironed out, and the moderate 20th century warming was accentuated by a host of manipulations. Without the hockey stick, there’s just nothing wrong. It’s not broke, don’t try to fix it.
And second, we’ve heard: “most scientists agree” that CO2 will raise temperatures by x amount? Funny that the IPCC claimed a causal correlation between CO2 & temperatures, until about 2004 when the ipcc was reluctantly forced to retract their claim. Yes, the ipcc has retracted their claim of a CO2 / temp causal correlation. As it stands there’s no empirical evidence of any sort that CO2 causes climate warming, and indeed now the ipcc is maintaining that CO2 is both a cause and an effect of temperature change, which, unless CO2 was only an insignificant contributor to warming, would without a doubt lead to a runaway greenhouse with boiling oceans. But we never had a runaway greenhouse, despite co2 being as high as 7000ppm in the past. No, most scientists shouldn’t agree. The evidence is that CO2 does nothing to climate temperatures.

Harry van Loon

Not another!!! For Heaven’s sake.

The spin is on. The Swedish national news had it as one of its top stories, and we learned by the reporter responsible for the public Television that 40% of the terrestrial land will be impossible for humans to live on. For our amusement the weatherman directly afterwards told us we just had the coldest 24hours for the month of March in Sweden since 1979.

Dang, it’s worse than we thought. /sarc
Don’t any of these “scientists” have a clue? Don’t any of these “scientists” have any shame? Don’t any of these “scientists” realize how hostile the public is going to be towards them when they decide they have had enough and rise up?
I thought these people wanted to make a name for themselves. You know, go down in history for something noble, something wonderful. Do they really want their children and their children’s children ashamed of them? Do they really want to go down in history as clowns and puppets at the very least – thieves and murderers at the worst?
They’re all bloody scienTITS, the lot of them.

Neil Jordan

A search for “shakun” on WUWT yields 20 previous encounters.

Latitude

is warmer than it’s been during 70 to 80 percent of the last 11,300 years…….
….is colder than it’s been during 20 to 30 percent of the last 11,300 years
Early Holocene warmth is followed by ~0.7°C cooling through the middle to late Holocene….
…present day warmth of 0.7C is back to business as usual
and this makes it all look ridiculous…….
http://www.foresight.org/nanodot/wp-content/uploads/2009/12/histo3.png

Ron

97% of Climate Scientists recommend Sensodyne for sensitive teeth.

MattA

Woulnt human activity in the last centuary significantly affect pollen levels through agriculture.Would this inself create a hockey stick?
Methinks this also has all the same problems as tree rings for measuing temperatures.
What about CO2 contamination of results – Higher CO2 means more plant growth therefor more pollen, therefore contaminated results.
Is this contamination of results not exactly the same as what happend with the Tiljander Sediments used upside down by Mann.

Mike Mangan

I think Craig Loehle’s head just exploded.

alcheson

My take away from the headlines, even if it IS true (maybe it is, maybe it isn’t), is that over the past 11K+ years, current temperatures have been exceeded 30% of the time (today’s temperatures are basically only slightly above average), even though CO2 levels were lower then than they are today.

This one raises even more questions then Mann’s work did. Where I am sitting here in Calgary ±12,000 years ago we have about 4km of ice. By ±10,000 years ago none and I am supposed to believe all that melt happened at temperatures lower then today. I think I am being asked to make some large leaps of faith. Faith is not science. Methinks the calibrations being made are via thin air.

cui bono

All this talk of ‘record’, ‘unprecedented’ and ‘alarming’ temperatures and we’re only in the 2nd quartile? Meh.

http://www.ecowho.com/foia.php?file=0938018124.txt
I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more in the proxy data’ but in reality the situation is not quite so simple. We don’t have a lot of proxies that come right up to date and those that do (at least a significant number of tree proxies ) some unexpected changes in response that do not match the recent warming. … I am not sure that this unusual warming is so clear in the summer responsive data. I believe that the recent warmth was probably matched about 1000 years ago. I do not believe that global mean annual temperatures have simply cooled progressively over thousands of years as Mike appears to and I contend that that there is strong evidence for major changes in climate over the Holocene (not Milankovich) that require explanation
Until someone can explain why there was pressure to tell a nice tidy story, and why (if) that pressure went away, I’m not going to take reconstructions like this seriously.

They are mendaciously spinning false facts. The planet is currently in a cooler part of the Holocene. The Holocene has been quite a bit warmer than now, and those episodes were all beneficial for the biosphere.
It appears that we are cresting the hill, with no warming trend over the past decade and a half. What we really should be concerned about is a return to pre-Holocene temperatures. Instead, we get this alarmist propaganda.

Jer0me

OK.

Earth Is Warmer Today Than During 70 to 80 Percent of the Past 11,300 Years

How about:
Over the past 11,300 Years, 20% to 30% of the time it was warmer than today.
There. that’s not so scary, is it?

Ximenyr the 2nd

from the paper–
Although our temperature stack does not fully
resolve variability at periods shorter than 2000 years,
such high-frequency changes would only modestly
broaden the statistical distribution of Holocene
temperatures (Fig. 3 and fig. S22).Moreover,
we suggest that accounting for any spatial or seasonal
biases in the stack would tend to reduce its
variability because of the cancellation of noise in
a large-scale mean and the opposing nature of
seasonal insolation forcing over the Holocene, causing
the Holocene temperature distribution to contract.

Peter Miller

Just another sad case of grant addiction..

MarkG

So 20-30% of the last 10,000 years has been warmer than today without any EVIL SUVs spewing out BABY-KILLING CO2.
What are we supposed to be worried about again?

intrepid_wanders

It gets better.

22 This study includes 73 records derived from multiple paleoclimate archives and
23 temperature proxies(Fig. S1; Table S1): alkenone (n=31), planktonic foraminifera Mg/Ca
24 (n=19), TEX86 (n=4), fossil chironomid transfer function (n=4), fossil pollenmodern analog
25 technique (MAT) (n=4), ice-core stable isotopes (n=5), other microfossil assemblages(MAT and
26 Transfer Function)(n=5), and Methylation index of Branched Tetraethers(MBT)(n=1). Age
control is derived primarily from 14 27 C dating of organic material; other established methods
28 including tephrochronology or annual layer counting were used where applicable.

http://www.sciencemag.org/content/suppl/2013/03/07/339.6124.1198.DC1/Marcott.SM.pdf
So, from 73 records (not databases, but “n”) and 1000 Monte Carlo simulations you interpolate and get your error bars for 12,000 years of data. All I can say is WOW. Talk about Pure F’in Magic. Do climate scientist work at all these days?

Justthinkin

“beesaman says:
March 7, 2013 at 2:54 pm
I predict more and more nonsense of this sort, right up to the moment it starts costing governments money.”
Ohoh. Not good, beesaman. I don’t know about the EU, OZ, etc, but in the good old USSA, they never run out, as long as there is a tree for them to make into paper to print money with.

Girma

Another hockey stick – this one billed as ‘scarier’ than Mann’s
Here is the real hockey stick=> the solar activity of the last 100 years:
http://www.woodfortrees.org/plot/sidc-ssn/mean:1056/normalise

intrepid_wanders

Okay, so that was worded different than further down,

270 8. Global Temperature Reconstruction from Sparse Dataset
271 To examine whether 73 locations accurately represent the average global temperature
272 through time, we used the surface air temperature from the 1×1° grid boxes in theNCEP-NCAR
273 reanalysis (83)from 1948-2008 as well as the NCDC land-ocean datasetfrom 1880-2010 (84).
274 (Fig. S13 and S14).

I will wait for the cliffnotes 😉

EW3

Try to fight against the tide of misinformation out there about AGW is akin to being a zoo keeper giving an enema to an elephant that has been constipated for 3 months. !

Bruce Cobb

It’s scary all right. In the same way that horror movies are scary. Nothing to do with reality though. I doubt it will fool many.

Jared

love how stable temps were before the deep fall in the little ice age. maybe that fall is the cause for the rebound warmth. After all the scientists have proven temps used to be stable.

knr

‘projections of global temperature for the year 2100,’
when none of us will be around to be reminded of this BS , which is really ‘useful’

Adam

I knew it was hotter than I always feared, and now I have a graph by some scientists to prove it! When will Marcott get his Nobel?

Bob Diaz

(Read with total lack of interest) Oh wow, I am sooooo fearful, now I want to give up all my freedoms and money to a bunch of mindless bureaucrats. (Come on alarmists, you can do better than that.)

Athelstan.

Something crooked this way comes….

Anthony add an update with the GWPF’s excellent headline,
EARTH COOLER TODAY THAN 28% OF THE PAST 11,300 YEARS

Colin Porter

Who would like to bet which way the distinguished Prof Mann tweets about this study?
Will he proclaim it as a major breakthrough and justification for his own reconstructions?
Or will he tweet abuse because they have upstaged him with an 11000 year reconstruction?

MattN

Which strip barks did they use? Or was is sediments? Archived data? Methodology? Can’t wait for Steve to completely disassemble this one. Will be fun….

Better question, did they as Steve McIntyre to be a reviewer?

Rob L

The big problem with this particular hockey stick appears to be the temporal resolution of the proxies – which is about 120 years average for the historic temps, but is only 1 year for the 20th century data they have tagged on the end.
This is effectively like using a large span running average and automaticatly smears out and removes peaks or hollows in temperature from the past – like the minoan, roman and medieval warm periods that were quite short in duration (1-200 years) but saw large 2°C rises in temperature .
To make this graph more honest you would have to run the same 120 year moving average over the modern temp record – in which case you wouldn’t have anything news-worthy as it would remove the modern peak and fill in part of the little ice age. Alternatively you have to use proxies with high temporal resolution (like ice cores such as Gisp2)

Gary Pearse

Just horrible pretensions to science. If the paleo part of the chart has a granularity of 120 years, and the present temps are the annual instrumental record (tortured to bend upwards), then it is clear that the medieval warm period (error bars) still make it stick up above the most stretched out hockey stick to date. Lets see what happens if we average the temp of the last 120 years to make an apples to apples comparison. This must be against some law or another or should be.

MattN

Just look at the first 500 years of the graph. Less then .01C variation for 500 years!!! Simply Amazing!!!

pottereaton
braddles

That “Mann et al reconstruction” in the figure is certainly not the original hockey stick in the 2001 IPCC report. Among other things, the original only went back 1000 years.