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:
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Why not show the graph of the entire period of the study? JP
[do you have a link to the entire graph that you would like to share? . . mod]
Peter Plail says: “Study shows climate changes – it has been hotter and colder in the past.In what way does this add anything to the debate?”
In two ways. It adds credence to similar results using differing methodologies. And, within the constraints of that methodology, it shows an unprecedented rate of change. JP
Martin says:
March 8, 2013 at 1:11 am
“After reading all the comments I’m finding it hard to figure out whether people come here to find out stuff or if they really prefer the science just all went away.”
Martin. It’s definetly the latter. JP
[I suppose your spelling is a clue as to why your comment is content free. . . still why not read around the other threads too and learn just how much science is discussed here. You will find the effort most rewarding . . mod]
Here’s Steven Goddard breakdown with graphs and references.
http://stevengoddard.wordpress.com/2013/03/08/new-data-tampering-record-disappearing-the-ice-age/
“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.”
Then after applying “Mikes Nature trick” we made this graph
http://wattsupwiththat.files.wordpress.com/2013/03/marcott-a-10001.jpg
Martin, when you have seen enough of these paleoclimate studies having been shown to have major flaws you don’t believe any of them until they have been properly audited by someone like Steve McIntyre. What climate scientist discusses Bill McKibben in an interview and expects to be taken seriously?
“Steven Mosher says:
March 7, 2013 at 8:34 pm
Weird.
They just concluded that as much as 20-30% of the holocene may have been warmer than today and 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?
Simple: we have evidence to reconstruct past temperatures. That evidence is all we have.”
Mosher, the problem is…. it isn’t evidence that is all the warmists have. They also have motive (billions of dollars and politics) ever since the formation of the IPCC to fudge/manipulate/construe/etc the data to fit a predetermined narrative. They have been caught numerous times doing so.
After it was decided that CO2 was to be the evil culprit which would destroy civilization as we know it, the IPCC replaced Lamb’s temperature graph with Mann’s fraudulent temperature reconstruction. Leading climate scientists praised Mann’s work as the Holy Grail of climate science, whereas in actuality the way in which the graph was constructed and sold to the public was nothing short of scientific fraud in the opinion of many who actually examined how Mann’s graph was constructed and what was shown and what was NOT shown.
Climategate demonstrated that a number of prominent climate scientists were willing to lie and/or exaggerate to further the NOBLE cause.
Published temperature histories for the time period since 1800 that keep changing every few months or couple of years, and always “corrected” to show the problem is even worse than we thought previously.
Satellite sea level rise histories that change (“corrected”) with time, just like the temperature graphs have done… always with the same result, the sea level rise is even worse than we thought previously.
The claim that man-made CO2 is making the ocean more acidic and will lead to catastrophic results in the very near future if we don’t stop producing CO2.
The IPCC claims the oceans are rising at an ever accelerating rate. However, the tide-gauge literature data shows the current, rather slow but steady as opposed to accelerating, rate started in 1850, long before CO2 warming could have been the cause.
The melting antarctic icecap fiasco (Steig et al).
And you ask, what evidence is there to show that temperatures in the past were warmer than today?
1) Ice cores
2) Old Viking farmlands in Greenland.
3) Lamb’s temperature reconstruction
These are things come to mind quickly, I am sure I could come up with even more if I wanted to think about longer.
What evidence do we have that current and 100 yr projected CO2 concentrations will not be a catastrophic problem?
1) CO2 concentrations in the past have more than once been several thousands of ppm, there was NO runaway global warming. In fact the earth still manages to go into and out of ice ages on a regular bases regardless of what the CO2 concentration is at the time.
2) Plants start to die off at concentrations under 200ppm. Thus 200ppm is BAD for life on earth. It is not too likely that at CO2 concentrations that are still quite near the low end as far as what is good for plants and is far less than levels that have occurred in the past will lead to mass extinction of the animals.
3) Like essentially all stable systems, It is highly likely that earth’s climate systems have predominantly negative feedbacks, otherwise the earth would have become uninhabitable LONG ago before man arrived on the scene.
4) Most plants grow much faster at 1000ppm CO2 than they do at 200 ppm. That is really great news for a world with billions of inhabitants that need to be fed.
5) Updates to the estimate of climate sensitivity to CO2 are begrudgingly, but continually revised downwards. What is is now?? 1.5 to 2C? It used to be much higher, seems not long ago best guess was 3.5C with possibly something as high as 7 or 8 C for a doubling of CO2. My intuition says it will be less than 1C since the feedbacks are expected to be negative, not positive.
I think I am done for now.
Alcheson
11300 years ago we were suffering a severe ice age. It has since warmed up, quelle suprise.
The two graphs are taken from Marcott et al, Fig.1. A) is the one on WUWT. B) is the one on DOT earth and MSNBC covers the full period of the study.
They explain
The real mystery for me is from whence came the very hungry caterpillar on New Scientist and Bishop Hill. I can’t see it in the paper.
A link to the entire graph is here,
http://www.thegwpf.org/content/uploads/2013/03/holocener.jpeg
poptech: “properly audited by someone like Steve McIntyre”
Thanks, poptech. Is that another climate scientist? I found a statistics website that looks interesting and a couple of climate scientists websites that seem to know what they are talking about. I’ll do a bit more digging and maybe compare. It’s sometimes hard to tell what’s what but I did some high school science so understand a bit of it. Pretty well starting from scratch with climate though. I think I’ve figured out the greenhouse effect but that’s about as far as I’ve got so far. It’s very complicated isn’t it.
Martin says: March 8, 2013 at 1:11 am
“…After reading all the comments I’m finding it hard to figure out whether people come here to find out stuff or if they really prefer the science just all went away…. I probably got this blog all wrong. I’m just learning. People told me it was a really good place to get info from a skeptics viewpoint. I thought it was about questioning science not dismissing any new study. (The reactions here almost makes you wonder if there’s not something to this CAGW after all.)…”
Martin, I think most of the frustration in here is that it appears this is probably useful information, but the spin is applied to the story immediately.
We don’t get a headline that makes us say: “Hey, for 30% of this interglacial (The Holocene) it was actually warmer than we are today! Isn’t that interesting? I wonder if this brings up a need to approach this all a little more cautiously?”
The very first line manages to slip in the phrase unprecedented warming, but is really talking about only the last 1500 years (and many, including me, doubt that is really the case, taking into account unadjusted mid 20th century data, and the sparsity of the MWP proxy data, but that is another story).
Nope, title, press release and headlines, and extracted charts all imply we are now hotter than ever, (to the average man who does not look at data very hard). The body of the abstract is fine, other than the obligatory paragraph saying “It’s worse than this, because it’s going to get a whole lot hotter, according to our models”.
In fact, they plainly state it has been warmer than today (pretty amazing , eh?) in this interglacial for 20 to 30% of the time, and the temperature is only now perhaps reaching the level of smoothed early Holocene temperatures, and is nowhere near as warm as the preceding interglacial.
To add insult to injury we get an illustration with a spliced on instrument temperature which looks like we are experiencing a massive temperature spike (well, all of 0.4 C), when we all know full well that the smoothing effect of the sampling and the nature of the proxy itself has removed most variance (spikes) from the older part of the proxy record. ie There were very likely a huge number of equivalent (to the recent record) or greater spikes and dips across the whole time span.
In other words, this is good and useful science, but written up and presented in a preconceived alarmist manner. And spun completely by some CAGW alarmists in their blogs and in the MMS.
Martin. If you can’t recognize when someone is using a data set to tell you a particulate story, you won’t see why more astute people may overreact.
I can’t explain it any better than this. I’d appreciate your comments on this.
Get ready for the next installment: “Today’s temperatures are warmer than the Holocene Climate Optimum and the Roman Warm Period and as for the MWP it was as cool as LIA.”
I vaguely recall that over the past several decades the biosphere has been greening. I also vaguely recall that the ice core records shows co2 rise follows temperature rise. Could it be a case of the chicken or the egg?
And now the NYT weighs in, screaming Global Temperatures Highest in 4,000 Years : http://www.nytimes.com/2013/03/08/science/earth/global-temperatures-highest-in-4000-years-study-says.html?nl=todaysheadlines&emc=edit_th_20130308
The good doctor and wanna-be Nobel Prizewinner Mann opines:
“We and other living things can adapt to slower changes,” Dr. Mann said. “It’s the unprecedented speed with which we’re changing the climate that is so worrisome.”
Yeah. There’s no human fingerprint on the recent warming that they can point to, but gosh, just look at the “unprecedented speed”.
Atarsinc
“And, within the constraints of that methodology, it shows an unprecedented rate of change. JP”
Please explain how taking samples at 120 year intervals allows anyone to draw any conclusions about short term (a few decades) rates of change of global temperatures. The periods weren’t necessarily consistent either, so all you are getting is snapshots taken at irregular intervals. And this from what is inevitably a noisy source.- given year to year variability.
As to your claim that this study adds credence to other studies, then I an puzzled. I wasn’t aware that anybody seriously disputed that temperatures have varied above and below current values in the past.
Anthony — Thank you for including Rohde’s very important warnings from Professor Revkin’s blog at the NY Times.
This is another case of “mixed data sets” — combined into one graph as if they were the same type and kind of data, leading the unwary into thinking the parts of the graph can be compared to one another.
Just not so.
It is a scientific error to combine such data into one graph in the first plce.
Yep. Don’t believe anyone who tells you it’s basic physics.
Earth Is Warmer Today Than During 70 to 80 Percent of the Past 11,300 Years
Thank (insert preferred name of chosen deity here) !!!
Martin – a vital discipline entirely lacking from the majority of whatever ‘climate science’ is is statistics – one of the ‘top guys’, Phil Jones, cannot even use Excel, according to his admission in climategate emails, hence our delight with, admiration of and praise for Steve. He has shovelled the dirt back where it belongs, the hole ‘The Team’ have dug for themselves with their political science, wonky guesswork, cheap shots in lieu of evidence, poor skillz and near-zero-finesse.
Our beef is mostly with the enablers, handlers and promoters of this sorry state of affairs – most of whom could not give a flying **** about the environment, starvation and drought, true pollution, overfishing, your health and prosperity or anything but their bottom line being nourished by the fake alarm in question.
How does one get a single global temperature record from 73 different individual temperature records from around the planet.
Well, actually, 73 is a pretty good number of records to get a global record from (especially if you are not using tree-rings this time).
But it depends on what you do with those 73 records.
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).
I would simply use an average over a grid system which is not what they did.
————
Secondly, they are using temperature records from 4 different isotope methods, dO18, mg/ca, Tex86 and Uk37.
Most of the individual studies which use these methods also are based on certain assumptions. Tex86 has consistently been off in my opinion. UK37 works pretty well. mg/ca depends too much on local conditions to be useful since the chemistry changes over time. dO18 is by far the best when it is controlled according the international SMOW standards. But too many people are using incorrect tempC/dO18 conversion formulae (especially the ones that have been recalibrated based on bore-holes).
———-
So, does that make this a good reconstruction.
Not a chance given the authors and how the isotope methods have been misused on many of the individual records.
Another scandal !
Where is the data?
poptech, thanks for posting the whole graph. Compared to GISP2, it looks like the whole graph is severely dampened. This proxy reconstruction shows +/-0.5°C over the past 12K years, yet GISP2 shows +/-9.5°C over the same time period.
“The analysis reveals that the planet today is warmer than it’s been during 70 to 80 percent of the last 11,300 years” also tranlates into:
“The analysis reveals that the planet today is colder than it’s been during 20 to 30 percent of the last 11,300 years”
So, actually there’s nothing to see here except that during certain periods in the past, the earth was warmer and contrary to all the warmist hype and catastrophism, we are nowhere near something unprecedented.
(apologies to anyone who has said it before me sincve I have not gone through the comments yet.)
Pops, meant to include GISP2, http://i49.tinypic.com/oji4b7.jpg
The desperate, almost frantic enthusiasm of many posters to reject the findings of this research are almost amusing. This research seems to have hit a nerve! They are perhaps indicative that it is the findings, and implications of the the research that are unwelcome rather than any real skepticism about the methodology or data.
As other posters have pointed out the research is in line with other methods and the results are consistent with other findings. The Holocene has had very stable GLOBAL temperatures during the rise of agriculture and city based civilisation. Cooling in the northern hemisphere is largely a result in the change in the date of perihelion.
The finding that the last century has seen an exceptional rise in global temperatures at the same time that physics indicates that extra energy is being retained by the rising CO2 is common to many paleoclimate studies.
Either people accept that these scientific studies are presenting reasonable findings derived from legitimate methodologies, or they invent conspiracy theories to justify the claim that the vast majority of scientists working in this field are falsifying the data and research.
Creationists already occupy this territory, claiming that evolution is not a scientific finding but an ideological campaign to impose empirical materialism. Climate science rejectionists seem to heading down the same road, but with the ideological motivation to enhance global governance to deal with the implied problem indicated by climate research.
The problem is that both sides tend to see a conspiracy both in the promotion of the results of science like this and in opposition to the research results which it is claimed is funded by commercial interests like the Donor fund and promulgated by the same tactics and often the same people that undermined the science on tobbaco, asbestos, DDT, CFCs, lead…..
REPLY: You mean in contrast to the desperate, almost frantic enthusiasm to accept it without questioning it?