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]](http://wattsupwiththat.files.wordpress.com/2013/03/marcott-a-10001.jpg?quality=83)
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
1College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.
2Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
- *To whom correspondence should be addressed. E-mail: marcotts@science.oregonstate.edu
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:
One more thing: By the end of this century, the global mean atmospheric temperature is predicted to increase, due to increasing CO2-induced warming, by some 4C according to the warmist-catastrophic cli-mythologists. However, we are already 13% into the century and the rise in this predicted temperature is ACTUALLY ZERO C.
If one were to take the century as commencing in 1997 and ending in 2096, the years without warming would be 17%. I don’t know by what kind of ‘science’ warmists keep on hanging on to their catastrophic warmist meme.
Markx:
Well and kindly said.
I want my hockey stick back.
Mine, Mine Mine!
Hello, (me=newbie)
I was wondering what would the graph look like if one were to use the highest resolution available prior to 1880, then a 120 year smoothed resolution for the 20th century temps? Would the authors of this paper accept that methodology?
Mosher wrote:
” …every savant here attacks a study they didnt read.
1. You think it was cooler?
2. You think it was warmer?
Which is it? If you think it was warmer.. On what basis? a piece of driftwood?”
Well Mosh, if you had actually read the comments of the savants you are attacking, you would have seen the answer to your question in Doug Proctor’s comment. To that I will add the local effects of the Holocene Thermal Maximum in the Paciific Northwest, when sagebrush and Ponderosa pine reached the shores of Puget Sound, treeline was hundreds of feet higher, and cactus colonized the San Juan islands. I frankly cannot believe the magnitude of ignorance you expressed with “a piece of driftwood.” Go read “After the Ice Age” by E.C. Pielou and get a clue.
Steven Mosher says
Show your work.
Henry says
A simple random sample of mine showed we are cooling, for at least the last 12 years
http://blogs.24.com/henryp/2013/02/21/henrys-pool-tables-on-global-warmingcooling/
Others seem to agree with my dataset
http://www.woodfortrees.org/plot/hadcrut4gl/from:2002/to:2014/plot/hadcrut4gl/from:2002/to:2014/trend/plot/hadcrut3vgl/from:2002/to:2014/plot/hadcrut3vgl/from:2002/to:2014/trend/plot/rss/from:2002/to:2014/plot/rss/from:2002/to:2014/trend/plot/gistemp/from:2002/to:2014/plot/gistemp/from:2002/to:2014/trend/plot/hadsst2gl/from:2002/to:2014/plot/hadsst2gl/from:2002/to:2014/trend
Furthermore, my data set on maxima shows we will be cooling for some time to come.
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
this will cause a shift in cloud formation and condensation causing some places to get much cooler whilst other countries might get some GH benefit- even though they will see less sun…
an example is Alaska (getting much cooler) and CET (getting warmer)
If you remove the part of the graph that represents the future what does it really look like?
Hard to see from what is provided.
Right on Time for AR5… “Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records.”
In the abstract, not a word about the methodology. In the press release, “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”.
All this is pretty vague and indeed subject to caution: another multiproxy, orange and apple study that just happens to generate a hockey stick… On top of the methodology, the stats will have to be looked very seriously. Of course, these kind of studies dispense with meteorology, its processes and how they can affect the samples and the meaning of proxy measurements.
Not a problem for Mosher who should become Michael Mann’s PR guy, as he should know better to be quite suspicious of these kind of ad hoc studies, especially in view of regional detailed studies such as Clim. Past Discuss., 9, 507–523, 2013.
http://www.clim-past-discuss.net/9/507/2013/ doi:10.5194/cpd-9-507-2013
The graph shown at the top of the page covers the last 2k years. T
As mentioned in the update above there is further information on:
http://dotearth.blogs.nytimes.com/2013/03/07/scientists-find-an-abrupt-warm-jog-after-a-very-long-cooling/
This includes a full version of the graph extended back the full 11K years. I am struggling to see the similarity between this and a hockey stick. Looks like the 2k year graph was cherry-picked for its visual impact.
@- REPLY: You mean in contrast to the desperate, almost frantic enthusiasm to accept it without questioning it?
There will be some enviro-activists who may use it as a cudgel to beat rejectionists over the head without much critical assessment of the research.
But most of the informed scientific community that are accepting this are doing so in the knowledge that it is valid research using legitimate methodologies with credible results.
[snip – not going there, especially when such accusations come from a feckless anonymous coward such as yourself – Anthony]
In Spanish media, citing the Europa Press Agency, the press release is quite different. They mix the findings of the scientific publication with nonsense declarations of one of the authors (Shaun Marcott) which lead to confusion, as they are personal opinions unrelated to the publication. He says that Global Temperature will increase between 2 and 11,5C by the end of the century. Which is the most absolutely crappy alarmist nonsense that I have heard in a long time, and definitely has nothing to do with the findings of his scientific publication. But there it is, in the newspaper and wrongly associated to a scientific publication, as if that was science at all.
Sorry, the declaration is from Peter Clark, one of the coauthors, not from Shaun Marcott.
I’m curious, is it normally acceptable to mix resolutions this way? I can see all sorts of erroneous interpretations arising, the kind that can get people killed in disciplines where physical objects and forces are involved.
e.g. I don’t think I would trust these guys to design a bridge, they might say it was stable over hundreds of years even if it fell down several times in a single year 🙂
“Well Mosh, if you had actually read the comments of the savants you are attacking, you would have seen the answer to your question in Doug Proctor’s comment. To that I will add the local effects of the Holocene Thermal Maximum in the Paciific Northwest, when sagebrush and Ponderosa pine reached the shores of Puget Sound, treeline was hundreds of feet higher, and cactus colonized the San Juan islands. I frankly cannot believe the magnitude of ignorance you expressed with “a piece of driftwood.” Go read “After the Ice Age” by E.C. Pielou and get a clue.”
I said show YOUR WORK. not point to somebody elses.
plus, you havent answered the question.
Warmer?
And dont just pick one location ti compare with 73.
“These guys used Mann’s math called RegEM (which was just made-up by Mann and is not really a proven statistical technique – its a cherrypicking weighting method depending on how you set it up – so we will have to see how they really did it – complex enough that only a few people will be able to figure it).”
##############
wrong.
another savant bites the dust.
tapio created this method.
http://www.clidyn.ethz.ch/imputation/index.html
I agree with Steve Mosher there is nothing wrong with RegEm so long as it is applied properly to the problem .
As Bruce Cobb points out above, the NYT news story fusses about now being the warmest period in 4,000 years. Well, yeah, if it was warmer 5,000 years ago, then that is correct. Did Man cause it to be warmer 5,000 years ago?
Poptech says:
March 7, 2013 at 8:48 pm
Mosher, B.A. English who has no scientific papers published is with Robert Rhode his BEST team member …didn’t see that coming.
How would a non-scientist recognize if the work was shown? Would he do a “review” of the grammar?
##################
Funny story. I started undergrad as a physics math major ( won some math competitions as a kid– like Mcintyre) but wasnt really challenged by those two areas. Philosophy, Literature and linguistics were a lot harder, so I got BAs in those. For grad school I attended UCLA working on a Phd in English,. I wandered into computational linguistics and of course to work in information theory ( as it pertains to textual analysis) I needed to go back and take stats courses. Since I was on a full ride scholarship I could basically sit in any classes I wanted. never bother to pick up a degree, already had too many. While working on my dissertation I found myself at Northrop Aircraft in Advanced Design, first working as a Operations Research specialist ( stats ), later I moved into crew systems design and finally into simulation and threat analysis. I had a boss who believed in moving people from department to department to turn them into experts in as many things as possible. he called me the sponge. Of course Northrop had great educational resources for people who were willing to learn, so If you were assigned a job to understand IR threats, then you had all the resources and training you needed.. I’m forever grateful to President Reagan without his foresight and funding choices.
Grammar? Funny thing there too. I find that when I switch my brain from art mode to math mode that I care less about it. Weird. anyway. have a nice day.
Finally: no scientific papers published?
personally, I never thought this was that big a deal, since I’m more well know for 600 page engineering reports ( most classified sorry ) You can probably find some of the unclassified ones if you know how to search DTIC. Science papers published? If that is your criteria, I’ll make you a big dollar bet.. say 25K
D.B. Stealey,
I like the “warmer than now” graph in your March 7, 2013 at 3:21 pm post. Is it available with an end date say to 2010? Thanks,RR
They hid the Dark Age Cold Period, the Roman Warm Period and the previous peaks and valleys. Most notably missing (I realize it’s off scale but I assume their “noise and oscillation free” trend continues to the earlier dates) is the Holocene Optimum. The sad thing is, the dumber than dumb media and herd, being unaware of the real paleoclimate indicators, have lapped it right up.
as usual, Steven Mosher always ignores my posts
http://wattsupwiththat.com/2013/02/20/its-the-sun-stupid-the-minor-significance-of-co2/#comment-1230143
Why waste time discussing this paper? It concerns climate and it comes from Oregon State University. Thus the probability of its being politics-driven and fraudulent is 100%.
Do you deny 15+ years of no warming in the face of rising co2?
Hooray – fun with statistics – This paper is just like saying it is unprecedented for a basbeball player to hit 3 for 3 in a game because he’s never hit over .290 in any previous season.
– – – – – – – –
Indeed, how was RegEm used in this new paper Marcott et al 2013 published by the journal Science?
We can see the past relevance of inappropriate use of RegEm to hockey sticks in A.W.Montford’s book ‘The Hockey Stick Illusion’ chapter 14 ‘A New Hockey Stick’. The following is from the book.
RegEm was used Mann et al 2008 PNAS ‘Proxy-based reconstruction of hemispheric and global surface temperature vriations over the past two millenia’. From that Mann paper,
In the ‘Hockey Stick Illusion’ Montford said,
So, since we have a new hockey stick in this new paper, have the authors applied RegEm like the inappropriate application of RegEm by Mann et al 2008 did? In other words, has the Mann et al 2008 precedent been used by Marcott et al 2013? Let’s look closely at that new paper.
John
… looks like a hockey stick via dipstick statistics.
How about statistics such as:
“Earth is now much COOLER than it was for 99% of the past 542 million years.”
or
“Earth is now slightly COOLER than it was four previous times during the past 500 thousand years.”
Somebody check my numbers.
What is so magical about 11,000 or so years, anyway, that trumps all the variations during all the other spans in Earth’s history?