Another exceptional doozy from WUWT - physically impossible global temperatures!

This is kind of funny if you're into denier humour. Anthony Watts likes people to think that he knows something about the Earth's surface temperature when he doesn't even understand the concept of anomalies. Today he is telling everyone that it's not just okay, it's correct to splice the record of ice cold temperatures in Greenland with those of the entire world, and claim it is global surface temperature. Wow!

Anthony posted a cartoon from Josh (archived here, latest here). It's sort of a copy cat of the new xkcd cartoon that is meant to put what's happening now into perspective. Instead what he's done would be a terrific parody of denier weirdness, if not for the fact that Anthony and his band of deniers believe it to be so. (Sometimes I wonder if Josh is poking fun at deniers, going overboard with silliness to see what he can get away with. Thing is, I don't think he knows the first thing about climate, or science. So, no.)

By the way, what I mean by physically impossible is that the temperature changes that Anthony Watts and Josh are claiming just could not have happened. If they had, there would have been evidence of an ice age 13,000 years ago that was at least as cold as the last glacial maximum (24,500 years ago) and evidence of major, major forcings both hot and cold. (Meaning very substantial, impossible to miss.) There isn't.


Can you give credence to anyone who believes that global average temperatures like this are, as Anthony Watts claims, "factually correct"? Sheesh. Talk about denial. This takes the cake. Go on. Have a look at at the Josh cartoon carefully. It is not possible.

The xkcd cartoon is a timeline of human development of the last 22,000 years, with a timeline of global temperature changes over the same period. What it shows is that 22,000 years ago when the world was coming out of the last glacial maximum, temperatures were thought to be about 4 or 5 degrees Celsius colder than they are today. The temperatures rose very slowly at first, then a bit faster (but still very slowly by today's standards), then relatively recently tapered off into the Little Ice Age before the current sharp increase.

Below is a chart that gives you some indication. It's a composite chart using data from Shakun12, Marcott13 and GISTemp. Take note of the cautions below.

Figure 1 | Global average surface temperature for the past 22,000 years. Anomaly from the 1961-1990 mean. Data sources: Shakun12, Marcott13, GISS NASA

The cautions are mainly to do with resolution. The paleo data (Shakun12 and Marcott13) are of much coarser resolution than the GISTemp data. The latter has annual data. The former two have data resolved at decadal to century level. You can't compare annual changes with decadal and centennial changes. The annual temperatures will have a lot more variability. There would have been temperature ups and downs in the past 22,000 years that don't show up in the data, normal internal variability for one thing. However I understand that it would be extremely unlikely that there has been anything like the rapid change we're currently experiencing.

When did the global temperature separate from Greenland ice temperature?

Deniers read a lot of disinformation about Marcott13 and haven't the will (and in some cases haven't the wit) to investigate these false claims for themselves. They don't appear to have heard of Shakun12.

Instead of accepting actual scientific research or figuring out what is physically possible and/or what has been observed through paleo indicators, the people at WUWT prefer the hodge podge of an impossible chart that is fed to them by a rank disinformer. I can't figure out how Josh cobbled his chart together. What he seems to have done is take an estimate from Annan13 for 22,000 years ago (at least he referenced that paper). (That research was based on a climate model as well as proxies, would you believe. Not that deniers would know that.) It estimated the Last Glacial Maximum (about 24,500 years ago) to be around 4 C colder than now.

I ask you. How could nobody not know if there were temperatures that were way colder than than the last glacial maximum, and occurred only 12,500 years ago (as Josh and Anthony Watts are claiming)?

Not only that, but the Annan13 data is not inconsistent with the research of Shakun12, which Annan13 references.

Back to Josh and his silliness. Somewhere along the line he spliced in some sort of anomaly from the Alley2000 paper, which in turn used data from Cuffey, K.M., and G.D. Clow. 1997. That is, he jumped between global temperatures and Greenland temperatures. And hardly anyone at WUWT said a word about it.

Then Josh got a bit more realistic, though I can't figure out what data he used for the Holocene. His temperatures were higher than they should be, but at least he gave up on the huge dips and spikes.

Eventually, he spliced whatever data he had onto the the HadCRUT4 global temperature record. It was here he ventured into silliness again, postulating that another Little Ice Age was as likely as a temperature rise.

Like I say his chart was a hodge podge. It's also not possible. There is no known mechanism by which global average surface temperature 12,500 years ago would have been a heap colder than the Last Glacial Maximum. Someone would have noticed by now and reported it.

Josh has other weird spikes and dips. He might have got those from using Greenland data. Who knows. For example, the small rise around 14,000 years BP in Figure 1 above, well Josh showed that as a rise of 3 C in 300 years, to a temperature higher than the 1961-1990 mean, would you believe. That's before the Holocene climatic optimum, which in the last 22,000 years was the highest the temperature got, till recently. It's just not possible.

I can't help but wonder if the fans of WUWT have ever thought to use their brain. Anthony has definitely got the audience he deserves.

Is Anthony Watts claiming Richard Alley is a science denier?

There was something else odd. Apparently Anthony Watts doesn't think that Richard Alley is "pro climate change". He's probably right about that, except I don't think that's what he meant. I think what he meant is that he thinks Richard Alley is a science denier. What Anthony wrote was: "The sources used are not just pro climate change like XKCD did". The main sources of the data used by Josh were GISP2 ice core data reported by Richard Alley, and HadCRUT4. Given that the difference between the xkcd cartoon and the Josh cartoon seems to be that Josh used Greenland temperatures instead of global temperatures for some of his chart, it can only be concluded that Anthony thinks that Richard Alley is a science denier. (He's not, in case anyone was wondering.)

The xkcd graphic and human history

The cartoon by xkcd was terrific, but it has had some criticism. Greg Laden goes into some detail about how it could be improved. It's not so much the temperature line, which is pretty close to actual. (Compared to Josh's cartoon, the xkcd one would be classed as perfect!) It's more about the history of humanity, which is too narrowly focused on the history of what is now the west, and doesn't give a full picture of humankind overall (and has some errors). Greg doesn't blame xkcd for that incidentally. His article is well worth a read.

Addendum on implications for climate sensitivity

Two additional points occur to me that are worth mentioning. One is the obvious. If temperatures fluctuated as much as Josh and Anthony Watts claim over the past 20,000 years or so, that means that climate sensitivity is very, very high. In other words, with a doubling of CO2 the skies the limit as far as temperature goes. The temperature wouldn't just be off the charts it would be off the charts boiling!

The other point (which is related) is that Josh cherry picked the bits he wanted from the Greenland temperature record. While he included some very low temperatures, he didn't say how low - just that it was "off the charts cold". Look at Figure 2 below. Look at the vertical axis. Josh's temperature was indeed off the charts - 16 degrees Celsius off the charts if you take the minus 30 C as the zero baseline. He didn't include the earliest part, which was also between minus 45 and minus 50 C, or up to 20 degrees colder than now. Do you think he figured he'd have to extend his chart, and realised that even the dimmest denier at WUWT might balk at that?

Figure 2 | GISP2 temperature, Greenland ice sheet. Temperature in degree Celsius as reported by Alley2000.

Added by Sou - 6:02 pm 21 September 2016 AEST

From the WUWT comments

It took quite some time before anyone at WUWT commented on the splicing. There wasn't a peep when I first saved the page. One popped up later on (archived here). It didn't take nearly as long for people to quote defamatory denier nonsense about Marcott13.


RWturner wanted something about some "huge warming", which was fast in geological terms, but very slow by today's standards:

September 20, 2016 at 12:21 pmOkay I know it’s a cartoon but I want just one nitpick, meltwater pulse 1A at about 13,500-14,000 years ago should show a huge warming and probably something written on the side like sea levels were rising 30-60 times faster than today.

Gabro posted a chart and pointed out that the record for Antarctica didn't match Josh's picture. That's not surprising. His picture of the time was a mix of goodness knows what and Greenland.

September 20, 2016 at 1:31 pm
Also, Antarctic cores show even the end of the Last Glacial Maximum (c. 18 Ka) still colder than the Younger Dryas, let alone its depths (c. 20-22 Ka). 

Javier put up a different chart and agreed that Josh got it woefully wrong:

September 20, 2016 at 2:35 pm
Correct. Younger Dryas temperatures were intermediate between LGM and Holocene. There is a problem with 18O in Greenland cores. That data is not supported by data elsewhere and by sea levels. 

jeff might or might not know that the xkcd chart was informed by science, whereas Josh's chart is a non-physical mess. I suppose he doesn't understand either one of them:

September 20, 2016 at 12:29 pm
so is Randall Monroe honest enough to correct his post and admit his error to his readership, or will he stick his fingers in his ears and say “nyaa nyaa nyaa”? 

urederra doesn't display any ability to think critically with this comment. He probably heard the phrase somewhere and thought it made him sound clever.

September 20, 2016 at 2:21 pm
Well, there is also this thing called critical thinking, which is something that any rational person must have. And if after drawing a cartoon showing how the Earth temperature has changed during the last 22000 years he still thinks that the temperature change during the last 100 years is 100 % due to mankind then he does not practice much critical thinking.
… or maybe he wants to jump into the Global Warming gravy train. 

Moa mutters something about changing the hypothesis based on new data. Josh doesn't get the current data right, so what hope has Moa got?

September 20, 2016 at 2:54 pm
More important than Critical Thinking is following the Scientific Method, always. That means, always examining new data to falsify your current hypothesis – and changing that hypothesis based on new data. 

jorgekafkazar fails to connect the dots, and not through lack of opportunity.

September 20, 2016 at 4:01 pm
He does point out that temperature spikes are damped out by the proxy data, then fails to connect the dot that the current jump (such as it is) may be merely a repeat of previous spikes of largely unknown origin.

Don B  blames Shaun Marcott for a misleading headline from the BBC. Thing is, it was Shaun Marcott that got the BBC to correct it. What Don B's comment demonstrates is a total inability to reason, as well as conspiracy theorising (nefarious intent, and Marcott must be wrong), and confirmation bias in extremis. Note his use of the word "admited". Yeah, he "admitted" what was clear as crystal in his original paper! Don's a dunce (to be kind).

September 20, 2016 at 12:35 pmSome interesting history is that the UK’s Met took down an article after Marcott had to publicly admit what they claimed about recent warming was not true. 

emsnews is an ice age comether, still hopeful against all odds, and three in a row hottest years on record.

September 20, 2016 at 12:43 pm
Except for the last 200 years and only in parts of Europe and North America, we have only proxy records. The chief two most important are the changing shorelines as the oceans rise or fall depending on ice levels and the marks glaciers make when the grow and retreat. There are no ‘degree’ data at all. Just proxies.
So any graph or chart is very much ‘guesstimates’ rather than hard, cold numbers. But the fact that glaciers were far greater in size and reach at various intervals is most important because the chances of this happening again is highly likely.

Anthony Watts is more concerned about whether the birth of Christ should be registered and what I and Joe Romm think about that. (Nice compliment, thanks Anthony.) (Answer: Nothing. It's fine by me. It's what marks the beginning of the Common Era.) What Anthony isn't concerned about or probably even knows, but should if he had the first understanding of climate science, is that Josh's chart is a shambles, a complete mess, utterly wrong, and physically impossible.

September 20, 2016 at 1:35 pm
Well the fact is that the birth of Christ is a point in history, used in many many climate science and many other scholarly articles where they cite anno Domini or A.D. and B.C.
“The terms anno Domini (AD) and before Christ (BC) are used to label or number years in the Julian and Gregorian calendars. The term anno Domini is Medieval Latin, which means in the year of the Lord but is often translated as in the year of our Lord.[8][9]:782 It is occasionally set out more fully as anno Domini nostri Iesu (or Jesu) Christi (“in the year of Our Lord Jesus Christ”). Dionysius Exiguus of Scythia Minor introduced the AD system in AD 525, counting the years since the birth of Christ.
Ref: https://en.wikipedia.org/wiki/Anno_Domini
So, unless they are prepared to wipe Wikipedia clean of it, history clean of it, and science clean of it, I think we are perfectly safe and justified in using it. And quite frankly, who cares if some wackadoodles like Sou (Miriam O’Brien) or Joe Romm get upset about it? Point them to the religious based writings of 350.org’s Bill McKibben and suggest they either condemn him too [or] kindly STFU.

jgriggs3 is sad to discover that xkcd is a fan of science, and knows a lot more about it that Anthony Watts (and Josh, and jgriggs3). That's odd, because xkcd is known for it's terrific science humour, which would fall flat if he weren't knowledgable on the subject.

September 20, 2016 at 1:29 pm
This makes me incredibly sad. I love XKCD (and his What if series), read it regularly. When I saw this cartoon it made me want to abandon the site. This is the same mistake that Michael Mann made with his hockey stick, tacking on modern measurements onto a proxy timeline. Munroe even doubles down on the error and adds the unproven, unrealistic model projections to it.
This must be how it feels when someone we trust goes to the dark side of the force. I really wish there was a way for me to express my anger with Munroe other than avoiding his comics in the future. 

Leo Geiger was the first person to note the incongruence.

September 20, 2016 at 1:29 pm
“This chart uses GISP2 ice core data…”
Folks don’t like Marcott, but are OK with Greenland as a proxy for the whole world??

Bruce Cobb is a denier through and through and doesn't know how to use data, or what it means.

September 20, 2016 at 2:23 pm
Greenland at least is real, and over time, apt to mirror what the rest of the planet does. Marcott on the other hand is pure Warmist hockey stick fancy, and pure nonsense. 

jim steele pops in to congratulate Josh for hoodwinking Anthony Watts and almost all the WUWT deniers. I'm probably giving Jim far too much credit. It's more likely that Jim doesn't know anything about climate, so he is hoodwinked too.

September 20, 2016 at 1:58 pm
Great job!
May I suggest adding tree line reached the shores of the Arctic Ocean around 9000 AD, further north than today. 

Joe_da  has it wrong. That's what happens when you don't move outside denier blogs. Marcott13 results will be refined over time as more information is collected, but there's no way it was discredited. It was an important piece of research. It's become a denier myth, showing that if deniers repeat a lie often enough, some dim deniers are bound to repeat it even though they don't have a clue what it means.

September 20, 2016 at 3:13 pm
Marcott 2013 is still alive! Last to resurrect it is XKCD
marcott is still alive – I thought even the most diehard climate alarmist accepted that the study has been throughly discredited

References and further reading

A timeline of Earth's average temperature since the last glaciation - cartoon by xkcd

Everybody Always Gets This Wrong, Even Smart People - article by Greg Laden about human history and the xkcd cartoon

Shakun, Jeremy D., Peter U. Clark, Feng He, Shaun A. Marcott, Alan C. Mix, Zhengyu Liu, Bette Otto-Bliesner, Andreas Schmittner, and Edouard Bard. "Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation." Nature 484, no. 7392 (2012): 49-54. doi: 10.1038/nature10915 (pdf here)

Marcott, Shaun A., Jeremy D. Shakun, Peter U. Clark, and Alan C. Mix. "A reconstruction of regional and global temperature for the past 11,300 years." science 339, no. 6124 (2013): 1198-1201. doi: 10.1126/science.1228026 (pdf here)

Annan, J. D., and J. C. Hargreaves. "A new global reconstruction of temperature changes at the Last Glacial Maximum." Climate of the Past 9, no. 1 (2013): 367-376. doi:10.5194/cp-9-367-2013