Guest Post by Willis Eschenbach
As a result of a tweet by Steve McIntyre, I was made aware of an interesting dataset. This is a look by Vinther et al. at the last ~12,000 years of temperatures on the Greenland ice cap. The dataset is available here.
Figure 1 shows the full length of the data, along with the change in summer insolation at 75°N, the general location of the ice cores used to create the temperature dataset.
Figure 1. Temperature anomalies of the Greenland ice sheet (left scale, yellow/black line), and the summer insolation in watts per square metre at 75°N (right scale, blue/black line). The red horizontal dashed line shows the average ice sheet temperature 1960-1980.
I’ll only say a few things about each of the graphs in this post. Regarding Figure 1, the insolation swing shown above is about fifty watts per square metre. Over the period in question, the temperature dropped about two and a half degrees from the peak in about 5800 BCE. That would mean the change is on the order of 0.05°C for each watt per square metre change in insolation …
From about 8300 BCE to 800 BCE, the average temperature of the ice sheet, not the maximum temperature but the average temperature of the ice sheet, was greater than the 1960-1980 average temperature of the ice sheet. That’s 7,500 years of the Holocene when Greenland’s ice sheet was warmer than recent temperatures.
Next, Figure 2 shows the same temperature data as in Figure 1, but this time with the EPICA Dome C ice core CO2 data.
Figure 2. Temperature anomalies of the Greenland ice sheet (left scale, yellow/black line), and EPICA Dome C ice core CO2 data, 9000 BCE – 1515 AD (right scale, blue/black line)
Hmmm … for about 7,000 years, CO2 is going up … and Greenland temperature is going down … who knew?
Finally, here’s the recent Vinther data:
Figure 3. Recent temperature anomalies of the Greenland ice sheet.
Not a whole lot to say about that except that the Greenland ice sheet has been as warm or warmer than the 1960-1980 average a number of times during the last 2000 years.
Finally, I took a look to see if there were any solar-related or other strong cycles in the Vinther data. Neither a Fourier periodogram nor a CEEMD analysis revealed any significant cycles.
And that’s the story of the Vinther reconstruction … here, we’ve had lovely rain for a couple of days now. Our cat wanders the house looking for the door into summer. He goes out time after time hoping for a different outcome … and he is back in ten minutes, wanting to be let in again.
My best to all, rain or shine,
w.
PS—When you comment please quote the exact words you are referring to so we can all understand exactly what you are discussing.
Insolation clearly affects temperature, as shown by Figure 1, and long known. Indeed, its high latitude figure is what ends glacial intervals and starts interglacials.
However insolation depends both on solar radiation and Earth’s orientation to the Sun, ie, its axial tilt, and other Milankovitch cycles.
And that is at a time when, according to the logarithmic effect of the particular gas, increasing amounts of CO2 would have a far greater effect on raising Temperature
It is truly misleading to present the ice core CO2 with out mentioning that there is 40-60% losses of CO2 from cores as they decompress and form micro fractures during extraction from the ice mass.
If one backcalulates these losses, a 260 ppm CO2 becomes over 400 ppm, suggesting that CO2 was the same or higher than it is not during most of this period.
It is dishonest to pretend that ice core CO2 measurements are anywhere close to being absolute values.
Thanks.
I know that you meant “now”, not “not”.
Backcalculating sounds like extrapolating, i.e. modeling badly stuff that wasn’t measured. The idea that there was 400ppm CO2 somewhere in recent past requires some extraordinary evidence as an extraordinary claim. CO2 depletion during the last glaciation is what I regard as a fact.
Charles Higley January 8, 2019 at 12:23 pm
Dishonest? You can osculate my fundament with those kinds of untrue accusations. I am many things. Dishonest is not among them. I am an honorable man. Perhaps you are not aware of my species, I don’t know, but we don’t take kindly to being accused of dishonesty.
Next, regarding CO2 and ice cores, here is the recent record of CO2 from six different ice cores compared with the Mauna Loa observations. Please point out to me where the “40-60% losses” are occurring.
And in the meanwhile, let me invite you to keep a civil tongue in your head.
w.
Thanks for using the technical, Latinate terms “osculate” and “fundament”!
This is after all, a scientific blog.
Thanks Willis.
Not to agree with the accusation or diminish your response, but this plot has had the ice core data offset by about 80 years to match the Mona Loa data on the theory that the process of getting from snow fall to ice encased air bubbles allows access of air to the older firn. In fact there are good arguments from other proxies and direct measurements of atmospheric CO2 as far back as the early 1800s that the ice core CO2 records are non-conservative and miss and short duration (100 year) variations.
DMA,
There is no 80 years offset to “match” the ice core data with the Mauna Loa data. That accusation by the late Dr. Jaworowski is because he looked at the wrong column of the ice age instead of the average gas age in the Siple ice core as measured by Neftel e.a.:
http://www.ferdinand-engelbeen.be/klimaat/jaworowski.html#The_arbitrary_shift_of_airice_data
Pores in the ice are gradually closed until 70-100 m depth but most of the time open enough to allow exchanges by diffusion over 40 years (Law Dome) to several thousands of years, so that the gas composition still is near what is measured in the atmosphere.
Etheridge e.a. measured CO2 in firn at Law Dome until closure depth and in ice at the same depth with the same equipment (GC) and found the same CO2 levels, which were in average about 10 years “older” than at the surface, while the surrounding ice was already 42 years old:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_firn.jpg
DMA,
About the resolution of ice cores CO2, that heavily depends of the local snow accumulation. At coastal Law Dome, that is about 1.2 m ice equivalent of snow per year, which gives a resolution of of about 10 years over a period of 150 years. For high altitude inland cores, that is a few mm per year, with a resolution of 560-600 years, but over a period of 420 to 800 kyears.
As different ice cores overlap each other, ice cores with extreme differences in accumulation, temperature and resolution show the same CO2 levels over the same periods within a few ppmv.
Many of the older direct measurements with chemical means were taken at places which were completely unsuitable for “background” CO2 levels: in the middle of towns, forests, under, in between an over growing crops… Measurements taken at sea or coastal with wind from the seaside show CO2 levels around the ice cores.
See my comment on the late Ernst Beck’s compilation:
http://www.ferdinand-engelbeen.be/klimaat/beck_data.html
Willis, I don’t think Mr. Higley was accusing you of being dishonest. Still his logic isn’t logical. If micro-fractures formed due to decompression, CO2 in the core bubbles would equilibrate with current atmospheric CO2 and every year would show 400 ppm.
“Osculate my fundament…”
Nice phrase. I never heard it before, but I like the way it rolls off the tongue.
Charles Higley’s response is a little strong, but it doesn’t sound like he’s calling you dishonest, Willis. He’s just making a general statement about the accuracy of the CO2 measurements in ice cores. I haven’t seen that claim, but he does raise a good point about the problems of measuring gases in ice cores. This 1997 study in PNAS, “Gases in ice cores”, addresses those problems:
https://www.pnas.org/content/94/16/8343
I did not see anything about 40 to 60% losses of CO2, but I did see that gases mix quite a bit in the upper layers until they are finally compressed enough that gases no longer migrate, meaning that it’s difficult to tie the ratio of gases in a sample to a specific year or even decade (or longer). That’s only one of several problems with measuring gases in ice core samples.
First, Mr. Higley said “It is dishonest to pretend …”
He’s accusing SOMEBODY of pretending, and SOMEBODY of being dishonest. You can claim that he’s really talking about Hillary Clinton or some unknown person, but me, I take such accusations in the spirit that they are offered.
Second, when it comes to these kinds of disagreements, I’m interested in what HE says about it. They are HIS words. So I’m sorry to say it, but unless he’s appointed you his spokesdude, I fear your claims about what he did or didn’t mean are of little interest to me.
w.
Right. He used the words “dishonest” and “misleading”. It’s not my job to be Willis’ defender, but c’mon guys words are words.
There are some data that does suggest that ice cores tend to underestimate CO2 and particularly CO2 variation. Estimates based on leaf stomata almost always give moderately higher numbers and much more variation, suggesting that time-to-closure and diffusion blurs short-term variations in ice core data.
https://www.geocraft.com/WVFossils/Reference_Docs/Last_interglacial_CO2_stomata_Rundgren_etal_2005.pdf
https://www.researchgate.net/publication/258775861_Stomatal_proxy_record_of_CO2_concentrations_during_the_Last_Termination_demonstrates_dynamic_climate_behaviour_and_an_important_role_for_CO2
tty, stomata are NOT valuable for determining the background CO2 levels. Most of the data were collected by Ernst Beck. He was kind enough to comment on one of my threads in agreement with that, saying that they were not representative of background levels.
w.
None of the data I referred to were collected by Ernst Beck. And stomata data are the principal CO2 proxy pre-800 KA when no ice cores exist.
It is more noisy than ice-core data, since it reflects the local CO2 level in early spring when the tree “decides” how many stomata to grow and CO2 is not as well mixed as is usually claimed.
tty,
Stomata (index) data are proxies, which reflect CO2 levels of the previous growing season at the place where the trees or shrubs did grow. That gives a local/regional bias, which is compensated for by calibrating the stomata data against ice cores and direct measurements over the past century.
The main problem is that the local bias may have changed over the centuries due to changed land use in the main wind direction or even the main wind direction may have changed over certain periods (MWP/LIA).
In short: if the average of the stomata data over the period of the resolution of ice cores differs, one need to re-calibrate the stomata data to the ice core average…
There are other proxies like foramins that reflect CO2 levels of the past up to a few million years, these are around the ice core data for more recent times.
tty January 9, 2019 at 10:23 am
You missed my point, likely my lack of clarity in my writing.
Stomatal measurements are not valid for determining the background level of CO2 because they are measuring ground level CO2. As a result, they are affected by a variety of local, ground-level sources of CO2, including decay of leaf litter, soil respiration. and the like.
So while they are definitely interesting and valid in their own right, they can NOT be directly compared to actual background level measurements such as those taken at the South Pole or Mauna Loa.
Best regards,
w.
Pretty sure he was referring to the data being dishonest and not those who unwittingly use it, and was referring to older ice core samples
Brooks Hurd, a high-purity-gas analyst noted that the Knudsen diffusion effect, combined with inward diffusion, is depleting CO2 in ice cores exposed to drastic pressure changes (up to 320 bars—more than 300 times normal atmospheric pressure), and that it minimizes variations and reduces the maximums
This is illustrated by comparing for the same time period, about 7,000 to 8,000 years before the present, two types of proxy estimates of CO2. The ice core data from the Taylor Dome, Antarctica, which are used to reconstruct the IPCC’s official historical record, feature an almost completely flat time trend and range, 260 to 264 ppmv On the other hand, fossil leaf stomata indices show CO2 concentrations ranging widely by more than 50 ppmv, between 270 and 326 ppmv
The CO2 old ice core data are artifacts caused by processes in the ice sheets and in the ice cores, and have concentration values about 30 to 50% lower than in the original atmosphere.
The age of bubbles in ice cores of a young age (less than 200 years) is assumed to be up to 80 years younger than the ice, which provides the necessary fit for todays measurements. There were actually more precise chemical measurements made in the 18th and 19th century showing high CO2 levels but which are ignored as being inaccurate
Pft January 8, 2019 at 5:19 pm
Oh, please, he said it was “dishonest to pretend etc.” … are you seriously claiming that the data was pretending?
w.
Well said W. Too many “haters” in this world unfortunately… Congratulations on being you. Cheers. L
Charles, Do you have a reference for that statistic? I am wondering why CO2 would be lost preferentially over the other gases present (esp. N2, O2 & Ar).
Salt is escaping from freezing water, so there is no denying the question has to asked. However, measurement has to be always calibrated and only then it will work.
I believe that applies to sea ice, not glacial ice.
Oddly enough CO2 diffuses better than N2 and O2. You can see this if you cork a PET soda bottle immediately after drinking it (it works best with big bottles). There will then be a high proportion of CO2 inside. After a month or so the bottle will be considerably deformed. The CO2 has diffused out but N2 or O2 does not diffuse in as easily, so the pressure inside the bottle decreases and atmospheric overpressure deforms the bottle.
tty,
Never heard that story, but you never know… What I have seen is that if there is little CO2 pressure left in the bottle and there was some warming by holding the bottle, the bottle deforms in the fridge simply by temperature.
It is known that plastics, even high density like PET are porous enough to allow passage of gases over long periods, but I don’t see why CO2 would pass faster than O2, which has a smaller diameter than CO2, including vibration. Moreover PET is slightly polar, so should retain CO2 more than O2 or N2.
That is anyway the case for ice, where the water-like layer at the ice-air border of the bubbles retains some CO2 better than O2 or N2. That is no problem at measuring time, which is under vacuum over a cold (-70 C) trap where water vapor freezes out and no CO2 can hide…
CO2 is measured from (sealed) inclusions of air, there is essential continuity between CO2 in the most recent ice-core and contemporaneous atmospheric measurements, and CO2 ranges between the same limits though 800 000 years. Accordingly, ice-core CO2 seems to be representative of atmospheric CO2.
Charles, I don’t understand your comment.
The processes you cite (decompression and micro-fracture losses) would seem to result in the loss of a percentage of the total trapped gasses. The relative proportion of CO2 would not be affected.
There are various mechanisms that can change the proportion of CO2 in an ice-trapped gas sample (solubility in meltwater, etc.), but I am not sure how your comment applies.
I am sure historical CO2 reconstructions have large error bars. Are you suggesting the reconstructions don’t even get the trend correct?
From whence comes the increased atmospheric CO2 which caused 400 ppm levels? Medieval SUV’s? Was atmospheric CO2 400 ppm during the 100,000-year glacial period preceding the Holocene Optimum? When and why did the atmospheric CO2 level increase? You’ve opened quite a large can of AGW worms here, Mr. Higley.
Charles, that aint right. Willis put out the data as it stands, no misrepresentation and no fudging. To throw out an unsubstantiated “your off by 40-60%” is not science or critical thinking, much less to accuse him of lying, misleading or being dishonest.
Willis puts out a lot of great data. Just a few observations on his first graph. The CO2 scale appears to be slightly shifted in time. The low CO2 spike precedes the 8.2 kyr cold event on his Greenland data instead of following it as compared to the Antarctic EPICA Dome C temp anomaly data where it was actually measured. Although it’s difficult to see where the 8.2 kyr event occurs on Willis’ x scale.
http://joannenova.com.au/global-warming-2/ice-core-graph/
Charles, if it is true that micro fractures are allowing some of the air in the inclusions to escape, how is it that only CO2 is escaping? Wouldn’t all the air escape, leaving the ratios the same?
It would be helpful if you were to provide links rather than making bald assertions.
A quick google of ice core co2 errors produces this and this but neither seems to strongly support your contentions.
I would also take you to task regarding your use of the word ‘dishonest’. It is fine to say something is misleading. It’s hard to avoid, in some way, being misleading. On the other hand:
When you use that word, you are saying that someone deliberately lied.
I am not saying this is a correct explanation for C Higleys assertion but the phenomenon of molecular sieves is pretty well studied https://pubs.acs.org/doi/abs/10.1021/ef000241s?journalCode=enfuem
It is conceivable that fractured ice could act as a molecular sieve that caused some discrimination in diffusion rates. This seems an obvious point that would have been addressed long ago, but we are dealing with climate scientheism.
Can I change that to COOtheism. Belief in the CO2 god.
BCBill,
If there is some discrimination between N2/O2 and CO2 when cracks occur and the high pressurized interior bubbles gases escape, then CO2 would be retained more than N2/O2, as its affinity to water ( or water-like ice surface) is much higher than for N2 or O2. At measuring time, grating under vacuum over a cold trap removes all gases + surface water out of opened bubbles and cracks, which would give increased CO2 levels, not decreased…
The same for cracks over time: as already said by several before, any CO2 diffusion would be from outside 400 ppmv to inside 180-300 ppmv as measured, not reverse (there is no reverse osmosis at work here…).
Surely the take home point here is not the absolute values of CO2, or that older readings may be somewhat “under-represented” due to depletion, but rather that (i) there is a clear pattern (rising rapidly from a “minimum” to current levels despite the relatively minor up and down fluctuations of the Temperature, & (ii) presumably a 4-5000 year “lag phase”. Perhaps only an “assumption” or “presumption” but is the minimum level of CO2 (somewhere in approx’ 5000 to 7000 BCE) correlated with the Glacial maximum and the rest of the graph until now correlating well with the steep rise in Temperature thereafter? If so, then assuming the lag is consistent we should be looking at a period of elevated and/or rising CO2 of similar duration to the entire “Interglacial”, correct? Also of course continues to beg the perennial question, how much of the current strongly increasing CO2 levels is due to Anthropogenic causes vs. natural rise (lagged) resulting from the strong rise in global Temperatures coming from Glacial Max. to current position of Interglacial?
Without. Not with out, Einstein.
I’d like to see the carbon cowboys climatesplain that CO2 vs Temp graph.
Oh 260 ppm is a glaciation, 280 is the optimum, and 350 is the hottest 1.5 K we can tolerate. So in 400 ppm the seas will boil.
Vinther dataset from Greenland is, btw, like Alpher, Bethe, and Gamow writing paper about the Big Bangd.
It’s time to get the coral data from USGS for long cycle AMO comparison.
http://www.climate4you.com/images/AMO%20GlobalAnnualIndexSince1856%20With11yearRunningAverage.gif
A climate proxy not much discussed is the average human height.
“… Steckel analyzed height data from thousands of skeletons excavated from burial sites in northern Europe and dating from the ninth to the 19th centuries. Average height declined slightly during the 12th through 16th centuries, and hit an all-time low during the 17th and 18th centuries …”.
https://www.sciencedaily.com/releases/2004/09/040902090552.htm
Sounds like another hockeystick, Chris …
w.
Not really, it depends on which ‘hockey stick’.
According to the summary ” Northern European men living during the early Middle Ages were nearly as tall as their modern-day American descendants …”.
The ‘hockey stick’ published in the Guardian for instance, a typical image that started the hysteria, eliminated the MWP altogether:
https://www.theguardian.com/environment/2010/feb/02/hockey-stick-graph-climate-change
Wars in the Little Ice Age shortened the stature of men, at least. Anyone tall enough was marched off to war, most died. Napoleon shortened the average height of French males by 2 inches, in short order.
Napoleon shortened the average height of French males by 2 inches, in short order.
He must’ve been very prolific…. 🙂
“in short order” . . . bonus points for tht!
Chris,
Many thanks for that link.
The author, Steckel, strongly links the human height variation with the climate. He states that the climate was several degrees warmer during the MWP, and this probably resulted in greater human height, due to factors such as longer growing seasons. Heights fell as the world cooled during the Little Ice Age, and then started to increase again as the LIA approached its end.
This is excellent confirmation of what most sceptics believe: warm is good, cold is bad.
I’ve been looking for human wellfare data sets, to see how well wellfare correlates with warming/cooling.
So far I have found only one, from the OECD. It starts in 1720. You’ll be surprised to hear that it shows human wellfare constantly increasing. Wellfare increased dramatically from 1900 to the present – yet more evidence that warm is good. If climate change is such a catastrophe, it seems odd that humans are actually doing very well indeed!
I would be very interested to know if anyone knows of other historical human wellfare data sets, preferably going back a thousand years or more. Historians may well have compiled such data sets, but so far I haven’t found any.
Chris
I suspect that human height is related to available nutrition. I believe that each person has built into their genetics a maximum height. Then during growth (especially the adolescent growth spurt), nutritional intake will modulate the actual growth. I think that is why athletes are taller now that we have a focus on good nutrition, even among young armature athletes.
See Fogel and Engerman, 1974, Time on the Cross, in which slave heights were directly tied to the amount of food slaves were allowed to eat.
I seem to remember having read some where that the on general the average heigt of an adult North Korean is 15 cm less than the heigth of his same age counterpart in South Korea. I do not know if there is any solid statistical data to be had that corroborate this, but if it is really true and verifiable then your suspision is probably well founded.
door (dôr) n.1. Something which a dog or cat is on the wrong side of.
LOL, with 4 dogs (around 350 lbs) and one cat (around 8lbs)…..Love the observation!
Mac
Great stuff!
There’s another head-scratcher for the ‘null hypothesis deniers’ (aka CAGW proponents) to try and ignore and/or discredit.
It will interesting to see what they come up with…
Do we see the ~800 year lag of CO2 after temperature in figure 2?
Personally I see a fit with my blurry eyes.
Looks more like a 4k year lag.
Me idiot, I will count the zeros better next time 🙂
Dataset says presented in 2009. Was this Vinther et al referenced in IPCC publications?
Mr. Eschenbach, your cat needs one of these $2000 cat doors: http://joannenova.com.au/2019/01/saving-the-planet-one-2000-cat-door-at-a-time/
The dataset says “…reconstruction presented in Vinther et al., 2009.” Was it referenced in any IPCC report? Greenland was two degrees warmer than today 8,000 years ago?
Interesting info Willis …
While Alley 2000 ends in 1855 (0.95 thousand years “before present” (BP meaning 1950), Vinther et al 2009 updates to the 1960-1980 time period. Kobashi et al 2011 updates the record further – thru 1993.
Andy May did a comparision of all three in a WUWT story a while back,
https://wattsupwiththat.wordpress.com/2016/07/29/a-review-of-temperature-reconstructions/
… which showed good agreement between all three, and compliments your work:
Andy did a nice, detailed timeline with good info as well:
He has a couple other good posts on Alley and Kobashi as well …
https://andymaypetrophysicist.com/climate-and-civilization-for-the-past-4000-years/
https://andymaypetrophysicist.com/kobashi-and-alley-gisp2-central-greenland-temperature-reconstructions/
Hmm … guess I should paid attention to the image urls 😉
Here is the interesting one IMO – the timeline with comments:
A. Scott,
All of your references for Andy May are for the NH Greenland data. They do not include Antarctic data. However, he did a global average where he combined over 5 different datasets from tropics, NH and SH data. You can see the significant differences from pole to pole.
https://wattsupwiththat.com/2017/06/09/a-holocene-temperature-reconstruction-part-4-the-global-reconstruction/
Your Figure 2 is a fair argument against the “CO2 is the thermostat” claim.
Err not really.
260 to 280 ppm is tiny watts
You can ALWAYS tell a misleading graph when they use ppm as opposed to the forcing
(psst and the lack of uncertainty)
Steve, the change in forcing is about half a watt per square metre. This is about the amount that is claimed to be the current imbalance in TOA radiation that is causing long-term ocean warming. Go figure.
Best to you,
w.
Also, Steve, the change in CO2 forcing is about the same as the change from 2000 to 2017. If you believe that CO2 is the secret temperature control knob, this forcing resulted in a temperature change of 0.3°C … which is about half of the warming of the entire 20th Century.
And if you believe the alarmists, half the warming of the 20th Century is not “tiny” …
Me, I don’t believe any of that, but YMMV …
w.
“The Door into Summer”…
Will no one else comment on the Robert Heinlein reference?
I figured some would notice …
w.
“The Door into Summer” [ 1956 ]
Sixty years from now, what will writers be able to use in this manner?
Will search engines bring up famous tweets by the likes of Alexandria Ocasio-Cortez and
Rashida Tlaib?
So much he wrote is relevant it is hard to pick one. He saw, and acknowledged, so much of the early cultural rot we are now dealing with. Much like SLA Marshall, men shining a light on issues that have effected our culture, and generally people just did not want to hear it, in any form. They were much more enamored of Asimov and Clarke, standing astride the currents of history, Left arm extended, bony index fingers pointing the “the future”. Yea, it could get depressing if it weren’t for the tide of contrarianism so much of the 25 and under crowd embrace. Hope for us yet.
Why doesn’t the cat just walk through the walls?
Ask Schrödinger
J.E. Box et al 2009 makes a good effort at extending the record further, creating a 168 year reconstruction for 1850 thru 2007 …
https://journals.ametsoc.org/doi/10.1175/2009JCLI2816.1
So we have between 40,000 to 80,000 years before the next glacial maximum.
Willis,how does this compare to Vinther’s 2006 long instrumental record of Greenland? This is a very long study over 200 years and co-authors are prominent alarmist UK scientists Dr Jones and Dr Briffa.
Looking at temps over this long period we find that much earlier decades are warmer than the last few decades and they even hold up well against some of the decades over one hundred years ago, back in the 1800s. See TABLE 8.
So what will be their excuse when the AMO changes to the cool phase, perhaps sometime in the 2020s? Or has it started already? Who knows?
https://crudata.uea.ac.uk/cru/data/greenland/vintheretal2006.pdf See TABLE 8 from the study comparing decades.
The temperature 10kBC is the concerning aspect of the above charts given the relatively small swing in solar insolation and the insolation is now going through its cyclic minimum.
If the data from Ice Cores is a bit Ïffy”, then hos does the data compare to other “Proxies”. ?
MJE
Looking at Fig 3 (Vinther recon), from 420 AD to 480 AD temps fell by about 1.8 deg C (the entry to the Dark Ages of Europe and as the Roman Empire collapsed). And from 1440 AD to 1500 AD (Sporer minimum), temps fell by a whole 2.0 deg C. And the minimum of reconstruction data in 1680-1700 AD average data point, the depth of the Maunder.
The point being the temps at high latitudes can fall relatively fast when the sun goes quiet, as the polar regions are Earth’s climate system radiators. This of course says nothing about the mid_Latitudes and tropics (most of the Earth). But it is just a warning, and one that clearly tells us CO2 is not in control of anything except the climate deranged minds of Socialists.
“Our cat wanders the house looking for the door into summer.”
An allusion to the Robert Heinlein novel “The Door Into Summer”
https://www.amazon.com/Door-into-Summer-Robert-Heinlein/dp/0345330129
https://en.wikipedia.org/wiki/The_Door_into_Summer
The novel was serialized in 1956. The protagonist, Daniel Boone Davis, has invented what is basically a Roomba in 1970 (30 years before the actual Roomba), He travels into the future — 2000 — via “cold sleep” and back to 1970, via a time machine, where he invents AutoCAD (12 years before the actual AutoCAD).
I read it around 1960. I have been complete disoriented by living in years that began after the years in which were set the Sci-Fi novels I read around 1960.
Thanks, Walter. Like you I read it in the early sixties. For me, the turning point regarding living in the novelists’ future was 1984 …
w.
The problem with 1984 is that a large number of “political activists” seem to regard it as an operating manual.
Read this if you want to undestand them:
https://ebooks.adelaide.edu.au/o/orwell/george/o79n/chapter3.3.html
Have the opposite problem after reading Frank Herbert’s Dune series, but still grokked Heinlein, though there’s not “time enough” for everything sadly!
Is it really fair to plot Antarctic EPICA ice core CO2 with Greenland ice core temperature anomalies? Why not plot Antarctic EPICA ice core CO2 with EPICA ice core temperature anomalies.
Or Greenland ice-core temperatures with Greenland ice-core CO2.
Oops, I forgot, Greenland ice-core CO2 data stubbornly refuse to conform with theory and are therefore never published.
However the Milankovich insolation curve is for 65 degrees north, so it would be less than ideal to compare it with Antarctic temperatures, whil CO2 is considered tio be globally well mixed.
tty,
Greenland ice core CO2 is unreliable due to frequent deposits of highly acidic volcanic ash from nearby Icelandic volcanoes. That reacts with sea salt (carbonate) deposits and produces in situ CO2 and/or extra CO2 at measurement time with the old full melting method. Volcanic ash deposits at Antarctica are far less and less acidic, which doesn’t give problems there.
Further, global CO2 levels are the same within 2% of full scale all over 95% of the atmosphere with a seasonal variability mainly in the NH and a 2-year lag between North Pole and Soyth Pole. It doesn’t make where you measure CO2, as long as far away from huge local sources and sinks.
Renee, the problem for me is the lack of resolution. Greenland gets lots of snow. Antarctica gets very little. This means that a) a given thickness of ice represents many more years in Antarctica than in Greenland, and b) firn closure time (the time to enclose bubbles completely in the ice) is much longer in Antarctica than in Greenland, so recent data is missing.
Next, CO2 is well mixed, so a record from anywhere is sufficient.
w.
Willis,
Here’s a quick plot of the difference in temp anomalies between Greenland NGRIP (similar to your plot) and Antarctic Dome C. They are very different. Dome C temps gradually rise since the cold 8.2 ky event and CO2 follows step, whereas Greenland shows a gradual decrease in T anomalies. Also, not sure why you are showing Greenland temp anomalies up to 3 degrees C, WOW. That would confirm that the past Holocene maximum was much warmer than present day T anomalies of 1 deg C.
Sure wish I could plot a graph instead of a link.
I didn’t realize that CO2, methane, and water vapor were consistent from the NH to SH. Thanks for that tidbit.
“That would confirm that the past Holocene maximum was much warmer than present day T anomalies of 1 deg C.”
Sure it was. That has been well known since the dawn of palynology and quaternary geology. Deciduous trees grew further north, animals occurred further north, treelines were much higher, glaciers were smaller or absent, sea-levels were higher, crops were grown further north than now etc etc etc.
There are literally thousands of papers from all over the world that show this, and it was once common knowledge but it seems that it has now mostly gone down the memory hole.
Another western Greenland study finds that the 19th century was the coldest of the last 10,000 years. So perhaps we are very fortunate to be living today and not 150 to 200 years ago? Here’s co2 Science’s summary of the Axford et al 2013 study.
Holocene Temperatures at the Western Greenland Ice Sheet MarginReference
Axford, Y., Losee, S., Briner, J.P., Francis, D.R., Langdon, P.G. and Walker, I.R. 2013. Holocene temperature history at the western Greenland Ice Sheet margin reconstructed from lake sediments. Quaternary Science Reviews 59: 87-100.
Background
The authors write that “predicting the response of the Greenland Ice Sheet to future climate change presents a major challenge to climate science,” but they say that “paleoclimate data from Greenland can provide empirical constraints on past cryospheric responses to climate change, complementing insights from contemporary observations and from modeling.”
What was done
As they describe it, Axford et al. “present Holocene climate reconstructions from five lakes along the western Greenland Ice Sheet margin, near Jakobshavn Isbrae and Disko Bugt,” where “insect (chironomid) remains from North Lake are used to generate quantitative estimates of summer temperatures,” and where “changes in sediment composition at the five study lakes are interpreted as evidence for ice sheet fluctuations, changes in lake productivity, and regional climate changes throughout the Holocene.”
What was learned
The six scientists report that “temperature reconstructions from subfossil insect (chironomid) assemblages suggest that summer temperatures were warmer than present by at least 7.1 ka (thousands of years before present), and that the warmest millennia of the Holocene occurred in the study area between 6 and 4 ka.” They also note, in this regard, that “previous studies in the Jakobshavn region have found that the local Greenland Ice Sheet margin was most retracted behind its present position between 6 and 5 ka,” and they say that they used chironomids to estimate that “local summer temperatures were 2-3°C warmer than present during that time of minimum ice sheet extent [italics added],” while indicating that the Little Ice Age “culminated at North Lake with 19th century summer temperatures that were colder than any other period in the record since deglaciation [italics added].”
What it means
Against this backdrop of data-based information, it should be clear to everyone that there is nothing unusual, unnatural or unprecedented about current temperatures along the western Greenland Ice Sheet margin – or anywhere else on the planet, for that matter – for temperatures there currently fall well within the extreme bounds experienced over the course of the Holocene. And it should also be realized that starting from the coldest point of the entire Holocene (the depths of the Little Ice Age), one could well expect that once started, warming (for whatever reason) could well be anticipated to be substantial.
Reviewed 17 July 2013
“osculate my fundament” – I had to look that up, and read the 2nd choice definitions before I caught on — Ha Ha
Glad you like it, Cyntha.
w.
This conversation is interesting, although not easy to follow.
I also wanted to look up the meaning of these apparently scientific terms. Then I noticed that the sentence began saying “… you can …”, and I was glad to confirm my suspicion that elegant sarcasm would be intended. I love such playing with words.
.-
“we’ve had lovely rain for a couple of days now. Our cat wanders the house looking for the door into summer. He goes out time after time hoping for a different outcome”
Cat is looking for a dry warm spot to watch the birds and other prey.
If you want him to leave for longer, cover his favorite spot, and put down a pet heat pad.
Once, I played a bird song CD, and my cats searched everywhere, but could not find …. just a little excitement in their dreary lives.
I assume the source data is the same as used by GRiP ?
As I understand it, Vinther used all available Greenland ice core data to make his reconstruction.
w.
Ah, yea, middle of winter. That is what happens.
The great interest in the Greenland (and Antarctic) ice sheets and the corresponding fear of catastrophic sea level rise are derived from events in the Eemian Interglacial with important differences overlooked including the much smaller size of the Greenland ice sheet this time around.
https://tambonthongchai.com/2018/12/21/eemian/
I don’t like this graph; it implies the next cooling is on schedule, heading for the glacial. Crap.
I’m still hoping there is something about the industrial revolution that will delay or save earth from the next glacial: Perhaps
1) the dirt and ash we threw out landed on the glaciers making them more sunlight absorbent,
2) the heating spilled out from our homes and factories, warming up the environment,
3) maybe a little warming from CO2.
Problem with ash and soot we are spilling is that it can be covered in matter of minutes by snow and rendered disfunctional. It will help us to maintain heat to some extent but change then will be sudden and system returns to its cold standard,
Now, that is a graphed dataset that should cause everyone to shiver!
Temperatures have been declining since circa 2,000 BCE.
And the recent temperature rise mostly occurred between 1920 and 1940.
1920 anomaly looks to be approximately 0.2°C.
1940 anomaly looks to be approximately 1.175°C.
Personally, I would be happier if we did not descend into another ice age. Though, I am unconvinced mankind has sufficient influence.
Excellent article and analysis, Willis!
Great: “Our cat wanders the house looking for the door into summer.”
https://knigger.org/heinlein/the-door-into-summer/lang/en/
Our cat “bella” does the same.
I open the door for her and she goes for a brief inspection.
Cats on inspection keep marten away from my automobile.
There are reports that sea level was a few meters higher 6-8 kyr compared to today, presumably a result of higher temperatures.
Some folks asked about why I used the EPICA CO2 dataset. I did it because I had it to hand and it covered the period in question.
However, it brought up the issue, so here are all of the ice core CO2 records that I can find that cover the period of the EPICA dataset.
Best regards,
w.
“. . . . . so here are all of the ice core CO2 records that I can find that cover the period of the EPICA dataset.”
Not very Mannly of you, Willis.
Most excellent, Peyelut!
The last two millenia is quite a hockey-stick. The last datapoint is 1960- 1980 ( I assume fractional 1960.0-1980.0, else it wouldn’t be 20 years).
Using KNMI climate explorer I estimated the temperature change from 1960 -1979 to the most recent 20 year average, in a band (74-76 N, 25-55 W) across Greenland.
Berkeley earth rose 1.3 C
NCEP/NCAR rose 1.5 C
Thus, around 1.4 C should be added to the last datapoint, which would make the blade of the stick even longer and penetrate the roof of the chart..
Yes. Actual measurements show that it is now about as warm as in the 1930’s and for a few years around 2005-2010 it may even have been slightly warmer than in the thirties:
https://www.nature.com/articles/s41598-017-01451-7
Great: “Our cat wanders the house looking for the door into summer.”
https://knigger.org/heinlein/the-door-into-summer/lang/en/
Our BLACK cat “bella” does the same.
I open the door for her and she goes for a brief inspection.
Cats on inspection keep marten away from my automobile.
https://www.catster.com/cats-101/different-cat-colors
What that academic drissel means :
Cats furs sport 2 colors:
– black: NO color
– red: colored cat.
common cats are a blends.
___________________________________________________
What about WHITE cats.
Well thei’re 256 in colour maps
– ALL notes in RGB or YMG
says
RGB red green brown
YMC yellow magenta cyan
https://www.google.com/search?q=ymca+rgb+colors&client=ms-android-samsung&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiJ5p-C9ODfAhWkqIsKHfVGDxEQ_AUoAXoECAwQAQ&biw=360&bih=560
What that academic drissel means :
Cats furs sport 2 colors:
– black: NO color
– red: colored cat.
common cats are a blends.
___________________________________________________
What about WHITE cats.
Well thei’re 256 in colour maps
– ALL notes in RGB or YMG
says
RGB red green blue
YMC yellow magenta cyan
https://www.google.com/search?q=ymca+rgb+colors&client=ms-android-samsung&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiJ5p-C9ODfAhWkqIsKHfVGDxEQ_AUoAXoECAwQAQ&biw=360&bih=560
What that academic drissel means :
Cats furs sport 2 colors:
– black: NO color
– red: colored cat.
common cats are a blends.
___________________________________________________
What about WHITE cats.
Well thei’re 256 in colour maps == shining bright
– ALL notes in RGB or YMG
says
RGB red green blue
YMC yellow magenta cyan
https://www.google.com/search?q=ymc+rgb+colors&tbm=isch&ved=2ahUKEwiQ67-J9ODfAhUegKQKHR98AD8Q2-cCegQIABAC&oq=ymc+rgb+colors&gs_l=mobile-gws-wiz-img.
___________________________________________________
really miss that f***ing edit function.
The insolation & CO2 graphs are great. Thanks.
For the benefit of those less well informed about climate & the behavior of Greenland’s ice cover, pls explain the apparent incongruity. Greenland was warmer during the latter half of the Dark Ages than it was during the Medieval Warm Period.
I have a question that has been bugging me recently. Ice caps, Glaciers, etc. move. Slowly flowing downhill toward the sea. When they take these ice cores and produce temperature records, do they (can they) account for where the ice was when it was deposited. How about elevation. Ice deposited today in Greenland is deposited at high elevation, so of course it is cold. How about 10,000 ya? What elevation was it deposited at? How much farther inland was it deposited than were it was sampled from?
Jeff in Calgary,
Most ice cores taken for measurements of ancient gases are drilled at the summits of ice domes, like Law Dome, Fuji Dome, Dome C, to prevent problems like dating the ice layer and its gas content.
I suppose that the lowest layers are just pushed sidewards, while the current height of the dome is not much different from the one in the far past.
There are exceptions like the Vostok ice core which was taken more downstreams and the third (DSS) ice core of Law Dome, to have a longer record with less resolution than at the summit.
In all cases it is only if you have distinct summer/winter ice layers that it is simple to know the age of the ice. At depth and low accumulation, one need to check with radar, electroconductivity, known volcanic deposits. Average gas age is a matter of accumulation, density and temperature and calculation, but often prone to revisions…
Your cat wants in after TEN minutes,Willis? Our last two would hit the wet concrete outside, disdainfully shake a paw and get straight back in before the door closed.
“Hmmm … for about 7,000 years, CO2 is going up … and Greenland temperature is going down … who knew?”
Who knew indeed! I’m sure that all the Team knew, but it’s not something you talk about in polite clime syndicate company, except how to hide the decline. We know we all would know if the data had supported the mene.
This study is study is reasonably consistent with three points that Steve McIntyre makes on his website
1) that most of the temp reconstructions provide limited scientific insight to the prior temps,
2) the relative differences in warmth between the present and the mwp is really indisquishable.
3) The warmth in both the present time and the MWP are only bumps in comparison of the entire holocene period
The other point is why none of the warmist look at marcott’s study and never say WTF –