NOTE: The Marcott et al (2013) paper and supplementary material is available at Science and an FAQ is now available on RealClimate.
Comment: 1 April 2013: Marcott for Dummies is out. However, Anthony Watts (in his seventeenth protest article) and the Auditor demonstrate that even after all this time and all their protests they still haven't even read the paper, claiming that Marcott et al "finally concede" something that was stated at the outset in the paper itself (page 1198).
The Auditor and his brigade are not at all grateful for the extra effort made by the researchers to explain their work to the layperson, and appear to be still trying to claim we are in the middle of the Little Ice Age and focusing on core tops instead of the core!
They obviously do not understand the connect between the modern record and the paleo record, even after years of nit-picking climate research. And I wonder will the 8% Dismissives heed this part of the FAQ:
Just as it would not be reasonable to use the recent instrumental temperature history from Greenland (for example) as being representative of the planet as a whole...The Auditor's cronies continue to make wild unfounded accusations. Conspiracy ideation most definitely (no wonder they don't like Lewandowsky and others showing them up in their true colours).
Click here for an expanded version of this comment.
Update 2+ So far there are now
(Comment 20 March 2013: I have looked through the WUWT articles and a lot of the comments. Anthony Watts, his guest posters and commenters provide an excellent illustration of warped mental models, ignorance, illogical thinking, dogmatism, conspiracy ideation, a preference for coloured pictures and avoidance of text, and the Dunning Kruger effect as well as the lynch mob mentality. It is also apparent that he has successfully rid his blog of all but maybe one person who is willing to consider scientific research. Watts' blog is aimed squarely at the bottom 8%.)
Of the rest, as with all the early protests, none of the protesters has indicated they understand the paper. Neither are the protesters interested in the overall reconstruction. It's the early part of the reconstruction that has filled in the gaps. There are already several reconstructions of the last several centuries, some even going back 1500 to 2000 years. In fact the protesters seem to be focusing not on the main substance of the paper but on the past 100 years or so. Odd, don't you think?
Now they are focusing entirely on this century rather than the entirety of the Holocene. If I understand Watts/McIntyre correctly, they are saying that there is an "error" in Marcott et al, which means earth hasn't been warming after all and we are actually still in the Little Ice Age.
- Protest 6 is almost identical to Protest Number 4.
- In Protest Number 7, Willis Eschenbach wants the raw data in the published paper, not satisfied with it being provided as a supplement. Steve McIntyre is, as usual, "baffled".
- In Protest Number 8, Fred Singer misquotes Marcott so he can shoot him down. Singer 'suspects what they did was' without appearing to be in the least interested in looking at the paper to see if what he 'suspects' was fact.
- Watts returns with Protest Number 9. Watts cannot figure out how anyone could know that the world has got a lot hotter over the past few decades, forgetting about the thermometers that were giving him so much grief only a few weeks ago, the melting arctic and all the other signals of our warming world. Neither can he understand how a paper jointly authored by four people and published in 2013 could differ in the slightest degree (sic) from the lead author's PhD thesis published two years earlier.
- Watts' Protest Number 10 is based on The Auditor's obsessive 'speculation' despite his being 'unable to replicate some of the recent features of the Marcott zonal reconstructions', though he admits it 'may be a difference in methodology'.
- In Watts' Protest Number 11, Anthony shows that The Auditor has been fiddling with numbers (ignoring the substance of the paper) and posits he has found a 'statistical processing error (selection bias)'. Makes me think of the saying: "Fools rush in where angels fear to tread'!
- In Watts' Protest Number 12, Anthony proclaims that The Auditor has found an 'error'. In fact he seems to be saying we have not yet emerged from the Little Ice Age!!! (Fools rush in!) Prof Peter Clark, co-author of the Marcott et al paper, has said they will prepare and provide an FAQ (a Marcott et al for dummies) which may (or may not) help McIntyre's 'bafflement'.
Near enough is good enough if it fools enough! (see below)
A paper published in the current issue of Science is getting some publicity. According to this recent research, in just a few decades we have managed to extricate ourselves from one of the coldest periods since civilisation began to begin the hottest period. And who knows when it will stop getting hotter.
The authors, Shaun A. Marcott, Jeremy D. Shakun, Peter U. Clark and Alan C. Mix have done a reconstruction of Holocene temperatures in a paper titled "A Reconstruction of Regional and Global Temperature for the Past 11,300 Years". You can get the paper and supplementary data here (subs required).
Here are two diagrams from the paper, showing one of their analyses. A shows the past 2,000 years compared with Mann et al (2008). B shows the same but going back 11,500 years before present (1950). (Click on any of the images in this article to see a larger version.)
Globally stacked temperature anomalies for the 5° × 5° area-weighted mean calculation (purple line) with its 1σ uncertainty (blue band) and Mann et al.'s global CRU-EIV composite mean temperature (dark gray line) with their uncertainty (light gray band).
The findings are not earth-shattering in that the research accords with what is already known. It is a very valuable contribution because it adds to and greatly refines existing knowledge. The beauty of the research is that it uses proxies from 73 sites around the globe, whereas previously much of what was known about temperatures in the early Holocene was based on ice cores or other more limited data.
What the Papers Say
What Science saysFrom the Editor's Summary in Science:
The climate has been warming since the industrial revolution, but how warm is climate now compared with the rest of the Holocene? Marcott et al. (p. 1198) constructed a record of global mean surface temperature for more than the last 11,000 years, using a variety of land- and marine-based proxy data from all around the world. The pattern of temperatures shows a rise as the world emerged from the last deglaciation, warm conditions until the middle of the Holocene, and a cooling trend over the next 5000 years that culminated around 200 years ago in the Little Ice Age. Temperatures have risen steadily since then, leaving us now with a global temperature higher than those during 90% of the entire Holocene.
The paper's 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.
What Deniers SayDeniers really don't like the Marcott et al paper. Already Anthony Watts has posted
Article 1: Watts is Wrong, Wrong and Wrong again!
Watts Wrong !In Anthony's first article he scoffed at the Mother Jones headline then demonstrated he hadn't read either Mother Jones or the paper itself, writing:
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.No Anthony, you suppose wrong. The take away message of most people is two-fold.
- The bigger message (for the general public) is the current rate of change is unprecedented in the Holocene (and probably in millions of years).
- The second message is that if it isn't already, the world will soon be hotter than at any time since the beginning of civilisation.
Watts Wrong 2
...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.Wrong again, Anthony. The study does not just focus on 2000 years, it looks at the entire Holocene. It looks at 11,500 years. (And what is he on about 'missing data'? The data is what the data is and is discussed at length in the paper and supplementary materials.)
Watts Wrong 3Anthony compounds his errors by getting it wrong once again (all these quotes are from a single paragraph, incidentally.)
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.No Anthony. "they" didn't say the last 100 years was the warmest. Marcott et al's research suggests that we may only now be approaching the highest temperatures, which according to their research occurred during the Holocene Optimum (between about 9,000 and 5,000 years ago).
Article 3: Watts third strike - and he's out (with the fairies)!
...they really aren’t comparing similar data sets...Not heeding his own "advice", Watts proceeds to tack Marcott's chart onto a denialist's clumsy (and faulty) drawing of past temperatures on Central Greenland's ice sheet:
Too wrong for words
- Is Watts really that ignorant, even after blogging on climate for several years? Does he really think that global temperatures fluctuated by more than 3 degrees Celsius in the past 9,000 years? Does he really not know that he was trying to compare temperature trends on Central Greenland's ice sheet with a global reconstruction?
- How does he justify chopping off 9,500 years of the Marcott et al reconstruction of global surface temperature and superimposing what's left of it onto some denier's drawing of temperatures in Central Greenland?
It must be the heat
Update: Two more protest articles on WUWT
- tack a single site arctic temperature series onto a global reconstruction and
- tack a single site modern land based record onto sea surface temperatures of a 15,000+ year paleo proxy series (single site).
1. Don Easterbrook has effectively repeated Watts' third post, comparing a global reconstruction with a single location in the Arctic (using the same flawed drawing of the latter). (Update) Don is persisting with this silliness in yet another post, apparently arguing the average global surface temperature of earth is around minus 30 degrees Celsius /s.
2. David Middleton has selected a single proxy set, Marcott No.2 from Barron et al. 2003 N. Coastal California High Res. Holocene/Pleistocene Oceanographic Data - 41.682 N, 124.930 W, 980 m water depth.
David plots the published sea surface temperature (SST) for Marcott No. 2 (which starts about 210 years ago and goes back 15,000 years or so) and tacks on a temperature series from a land-based location, Grants Pass (42.4 N,123.3 W) which goes back to around 1890 (approx 120 years).
Then David reduces the nearby land surface temperature record to a single data point for some reason (how/why he selected that temperature data point he didn't say - maybe he took the mid-point of the fast rising series).
Near enough is good enough if it fools enough!
David Middleton hasn't clarified why he did what he did, tacking on a single modern land-based surface temperature series to a single paleo series of sea surface temperatures. It could be the same reason that Don Easterbrook and Anthony Watts tacked the Marcott et al global reconstruction onto a reconstruction of temperatures in Central Greenland. A "near enough is good enough if it fools enough" philosophy not uncommon with fake skeptics.
The commenters seem to be concluding that Don and David have discovered 'flaws', but no-one has identified just what those supposed 'flaws' are. (Going by past WUWT performance, the mere fact of having an article on WUWT is enough for the throng to decide the author has proved "all the models are wrong"! Said article doesn't have to make any sense.)