By Andy May
This post has been translated into German by Christian Freuer here.
As I noted in my earlier post, “The IPCC AR6 Report Erases the Holocene,” the IPCC does not like to discuss the correlation between CO2 and temperature during the Holocene. It destroys their hypothesis that greenhouse gases and volcanos control Earth’s climate. Below is Javier’s plot of reconstructed Holocene temperatures, CO2 concentrations, methane concentration, and IPCC/CMIP climate modeled temperature. The plot is from Javier’s book, page 49.
As figure 1 makes clear, CO2 and methane (CH4) move opposite of temperature for almost the entire Holocene Epoch. As a result, the climate models compute a global temperature that increases steadily during the Neoglacial Period (~5,000 years ago until the end of the Little Ice Age around 1850AD), while proxy temperatures declined. The proxy temperature curve shown is presented as a “Z-score,” basically in standard deviation units, due to a furious debate on how much actual global cooling took place between the Holocene Climatic Optimum and the Little Ice Age. Everyone has an opinion, but no one knows.
The root of the debate is that the Northern Hemisphere, where most of the proxy data came from, cooled much more than the rest of the world, as shown in figure 2.
Global average surface temperature (GAST) is almost a meaningless number as figure 2 makes clear. GAST hides a great deal of important detail. Over long periods of time, due to Earth’s orbit and its spin axis tilt relative to the orbital plane (aka obliquity) the Southern Hemisphere (thin black line) and the Antarctic (light blue) temperatures often move opposite the Northern Hemisphere (heavy black line) and Arctic (green line).
The angle of Earth’s axial tilt is shown in Figure 1 as a purple line. You can clearly see that the Neoglacial began as obliquity began to decline. Figure 2 shows us that the Neoglacial was predominantly a Northern Hemisphere event. The Arctic also shows a significant decline, but only since 1000AD. The Southern Hemisphere and Antarctica bounce around (up and down about 0.5°C) but do not show a significant decline or increase.
We define the Mid-Holocene Transition (MHT) as being from about 3650-3250BC. Lots of climatically significant events happened then. The most significant was a southern shift in the Intertropical Convergence Zone, or ITCZ. It shifted abruptly southward about 3900BC. The shift is observed in sea surface temperatures (SST) from seafloor core ODP-658C as described by de Menocal and colleagues in 2000. Figure 3 is a plot of the Atlantic SSTs reconstructed from this core.
As you can see, the shift in ITCZ occurred either very early in the Mid-Holocene Transition, or just before it began. Javier provides us with maps showing the Holocene Climatic Optimum (HCO) and the Neoglacial ITCZ positions, we show his maps in figure 4.
A lot changed when the Holocene Climatic Optimum ended, and the Mid-Holocene Transition (MHT) began. As Javier writes in his book, on page 96, the European and North African climate went from an ideal climate for farming to a disaster by 3200BC. Failed farms were abandoned and people returned to being hunter-gatherers as the climate deteriorated. The orbital precession and obliquity driven change in the ITCZ, was accompanied by the Sumerian cluster of grand solar minima and the resulting climate changes caused a collapse in the European population. The Sahara Desert began to form, which drove people to the Nile valley where the first Egyptian Kingdoms were built on the backs of their slave labor.
The frequency of El Niños increased. They were quite rare during the HCO, but they became more common as the Northern Hemisphere cooled. Otzi the Tyrolean Iceman was killed and frozen into an advancing glacier. A large human genetic shift took place in Europe, the Chalcolithic Period transitioned to the Bronze Age, and the woolly mammoth went extinct. I refer the reader to Javier’s book for more details.
So, given all this, David Siegel noticed my previous post about the IPCC ignoring the Holocene, and asked me what the earlier IPCC reports have to say about the dramatic and well documented Holocene climate changes. We know they ignored them and their relationship with CO2 in AR6, have they always ignored them? I quickly looked through FAR and SAR, and found very little in them except they both mentioned that the Holocene climate appears to be driven by orbital forcing and the Holocene CO2 concentrations do not change much:
“…Holocene … [is not] considered [a reliable analogue] for a climate with increased concentration of greenhouse gases.”
(FAR, page 158-159).
They do not mention the possibility that their greenhouse gas hypothesis is wrong. They do acknowledge “that changes in orbital parameters alone can account for much of the changes from present climate found in the mid-Holocene.” (FAR, page 159).
In SAR, we see this:
“Large and rapid climatic changes occurred during the last ice age and during the transition towards the present Holocene period. Some of those changes may have occurred on timescales of a few decades, at least in the North Atlantic where they are best documented. They affected atmospheric and oceanic circulation and temperature, and the hydrologic cycle. … The recent (20th century) warming needs to be considered in the light of evidence that rapid climatic changes can occur naturally in the climate. However, temperatures have been far less variable during the last 10,000 years (i.e., during the Holocene).”
(SAR, p. 179).
Certainly, large, and rapid natural changes in climate can occur. No justification for the last statement in the quote is provided.
In TAR, we see the following:
“Long-term climate changes during the Holocene are consistent with the effects of orbital forcing, modified by the persistence of the Laurentide ice sheet (which finally disappeared around 6 ky BP).”
(TAR, p. 139)
And this:
“Natural variations in CO2 during the past 11,000 years (Figure 3.2c [our figure 5]) have been small (about 20 ppm) according to the best available measurements, which are from the Taylor Dome ice core (Smith et al., 1999; Indermühle et al., 1999). These measurements show a short-lived maximum around 11 kyr BP, followed by a slight fall, which may have been caused by increasing carbon storage in the terrestrial biosphere. Atmospheric CO2 concentration was about 260 ppm at its Holocene minimum around 8 kyr BP and increased towards about 280 ppm in the pre-industrial period. The same pattern and the same CO2 concentration levels over the past 8 kyr have also been shown in another ice core, BH7 near Vostok (Peybernès et al., 2000).”
(TAR p. 203)
Here is where the IPCC are the most honest, which is odd because this is the report that contained the notorious and widely ridiculed “Hockey Stick.” They acknowledge that the minimum CO2 was about 6000BC near the end of the HCO and that it increases after that until the modern day, that is throughout the Neoglacial Period cooling. But they do not do the obvious, they do not slap a proxy temperature record on top of it like Javier does in Figure 1.
“In the context of both climate forcing and response, the Holocene is far better documented in terms of spatial coverage, dating and temporal resolution than previous interglacials. The evidence is clear that significant changes in climate forcing during the Holocene induced significant and complex climate responses, including long-term and abrupt changes in temperature, precipitation, monsoon dynamics and the El Niño-Southern Oscillation (ENSO). For selected periods such as the mid-Holocene, about 6 ka, intensive efforts have been dedicated to the synthesis of palaeoclimatic observations and modelling intercomparisons. Such extensive data coverage provides a sound basis to evaluate the capacity of climate models to capture the response of the climate system to the orbital forcing.”
(AR4, p. 459) (italics added)
“The evolution of atmospheric trace gases during the Holocene is well known from ice core analyses (Figure 6.4). A first decrease in atmospheric CO2 of about 7 ppm from 11 to 8 ka was followed by a 20 ppm CO2 increase until the onset of the industrial revolution (Monnin et al., 2004).”
(AR4 p. 459)
So significant and complex climate responses resulted from a 20-ppm change in CO2, if orbital forcing is taken into account. They do admit that the Holocene is far better documented than previous geological periods. It is nice that they admit that natural climate change exists and can be significant and complex.
“Simulations of past climate can be used to test a model’s response to forcings larger than those of the 20th century”
(AR5 p. 776)
Impressive! They acknowledge that forcing larger than human-emitted greenhouse gases exist and have happened in the past.
“At a regional scale, models tend to underestimate the changes in the north-south temperature gradient over Europe both at the LGM [Last Glacial Maximum] (Ramstein et al., 2007) and at the mid-Holocene (Brewer et al., 2007; Davis and Brewer, 2009”
(AR5 p. 777)
Models underestimate Holocene latitudinal temperature gradients (LTG). Considering that changes in LTGs are a primary driver of climate change, this is more significant than they probably knew at the time.
“… SST biases contribute to model-data mismatch in the simulation of the mid-Holocene Asian monsoon (Ohgaito and Abe-Ouchi, 2009), even though the representation of atmospheric processes such as convection seems to dominate the model spread in this region…”
(AR5 p. 799)
Again, changes in convection are a primary driver of climate change and so are changes in sea surface temperatures. This is a clue that the IPCC/CMIP climate models are not working.
Discussion
Throughout all the reports, significant Holocene evidence, which is “far better documented” than earlier periods, that the IPCC/CMIP models are wrong is ignored or brushed away. I’ve been pointing out that the Holocene is important for ten years now. We have reasonably accurate historical and archeological records of numerous abrupt climate events since 10,000BC. Further, all proxies for the Holocene are more accurate than they are for earlier times.
It should go without saying, but I’ll say it anyway, if you can’t explain Holocene climate changes, you can’t explain climate. Ignoring the Holocene will not make it go away.
Works Cited
deMenocal, P., Ortiz, J., Guilderson, T., & Sarnthein, M. (2000, July). Coherent High- and Low-Latitude Climate Variability During the Holocene Warm Period. Science, 2198-2202. Retrieved from https://www.researchgate.net/publication/12453679_Coherent_High-_and_Low-Latitude_Climate_Variability_During_the_Holocene_Warm_Period
Kobashi, T., Severinghaus, J. P., Brook, E. J., Barnola, J.-M., & Grachev, A. M. (2007). Precise timing and characterization of abrupt climate change 8200 years ago from air trapped in polar ice,. Quaternary Science Reviews, 26(9-10), 1212-1222. doi:10.1016/j.quascirev.2007.01.009
May, A. (2018). Climate Catastrophe! Science or Science Fiction? American Freedom Publications LLC. Retrieved from https://www.amazon.com/CLIMATE-CATASTROPHE-Science-Fiction-ebook/dp/B07CPHCBV1/ref=sr_1_1?ie=UTF8&qid=1535627846&sr=8-1&keywords=climate+catastrophe+science+or+science+fiction
Vinós, J. (2022). Climate of the Past, Present and Future, A Scientific Debate, 2nd Edition. Madrid: Critical Science Press. Retrieved from https://www.researchgate.net/publication/363669186_Climate_of_the_Past_Present_and_Future_A_scientific_debate_2nd_ed
How does one even know what the temperature was like way back then? Sure you can look at a fossil or some tree rings or a piece of ice, but it’s not real time data like what we have today. I can’t fathom these geologists being able to reconstruct the temperature when humans were living in caves and were just discovering what fire was.
No one really knows. We know how the proxies work today, but we can only guess that they work the same way thousands or millions of years ago. And then combining proxies to get an estimate of global average temperature has all kinds of problems. I prefer looking at the raw proxies and just one at a time. See here:
How to compare today to the past – Andy May Petrophysicist
Unless physics changes over time, then most proxies will continue to work the same through time.
That’s fine for proxies that depend solely on “physics”, but some depend upon chemical signatures that can vary with time and location. Most uncertain are proxies that depend on biology, where the calibration of things like morphology, element ratios, and even isotope ratios depend on plant or animal species being studied. You have to make the assumption that species haven’t changed and their internal chemical systems haven’t changed. Fortunately, the Holocene is a pretty recent phenomenon, so these issues are likely minor.
until we get a time machine we’ll never know- maybe the aliens, when they finally land on the White House lawn will tell us 🙂
The aliens will be in for a shock when they meet Biden and Harris — probably will never come back after that..
“These carbon life forms don’t speak English; one speaks Dementia and one speaks Word Salad. Can we get an interpreter?”
Are not Harris and Biden evidence the aliens are already here ? 🙂
I believe Jill will have us Tacos prepared in advance for the coming alien smorgasbord.
Yes, but do aliens really eat little children? A libtard buffet may condemn mankind to some pest control.
Good chance they will re-route their plans to the Kremlin
Chinese spy balloons will land on the White House lawn long before aliens do.
We can’t even be sure time runs at the same rate in the past. General Relativity says a 100 year old clock is running slower than when new 100 years ago, because it has been accelerating for 100 years due to Earth’s 1 g gravitational field. We don’t notice it because we are also aging slower due to the same 1 g acceleration.
General relativity says no such thing.
GR states that a clock in a gravitational field will run slower than one that is not, period.
It says nothing about this difference changing over time.
Yes, but consider the average giant dinosaur: How did that massive thig stand up in our gravity?
That’s just one of many clues that gravity itself has changed. ferdberple said what I wanted to say.
The process by which C14 is allegedly formed, would be subject to even more erratic fluctuations, rubbishing that entire theory as well.
Add the evidence that there is a concerted effort to misrepresent the past, and suddenly archaeology and history has no more standing than a Superman comic.
Fred, just for a giggle, maybe you would appreciate this little lark:
https://www.greenpets.co.za/index.php/en/paranoid-goy/260-time-flies
Proxies are reconstructions of local climates. They prove local climates are always changing. Which strongly suggests the global climate is also always changing.
But when you average a batch of local proxies to estimate a global average, they are not as useful. Averaging tends to smooth the curves and obscure the trends.
The proxies also don’t include manmade causes of climate change. But they reveal large enough natural climate variations in the past so there is no reason to worry about manmade CO2.emissions.
I like to think about manmade CO2 emissions as recycling CO2 that was sequestered underground in coal, oil and gas, putting CO2 back into the troposphere where it originally was. Recycling CO2 is great for C3 photosynthesis plants. This concept makes leftists go berserk, so it’s good for entertainment too, if you enjoy leftists going berserk, as I do.
There is a reason to worry about our current interglacial ending, if you want to worry about something. The proxies suggest we are lucky to be living in the current climate. An interglacial and a warming trend are about as good as it gets. Let’s hope the 1975 warming trend did not end in 2015.
The only current problem with our climate is the Climate Howler Global Whiners annoying us about it. And their Nut Zero waste of money. The current climate itself is wonderful, compared with what we know from climate proxies.
Leftists control the climate change narrative but they can’t control the climate.
Climate Blog – Andy May Petrophysicist
Sadly, Richard it’s either the warming stops or we deal with this for another 20+ years. We should be grateful for this warmth but we can’t if with this huge political agenda. You can handle cold again can’t you? I know you live in Michigan, so I would take up learning some new winter sports if I were you. 🙂
You cannot solve a problem by creating (in this case wishing) a new one. Cooling is bad in itself. Political problems should be solved politically. That’s what democracies are for.
Agreed Javier. But at least cooling is a problem we can just deal with. It won’t be pleasant but we are more technologically prepared than in the 1970s. But our “democracy” becoming less and less democratic by the passing year. I was reading the other day about a WHO official urging the U.S to give it authority over pandemic policy; not very a pleasant considering how much they praise the Chinese government.
“But at least cooling is a problem we can just deal with. It won’t be pleasant but we are more technologically prepared than in the 1970s.”
It wasn’t bad living through the 1970’s. You couldn’t hardly tell it from today.
Authoritarian governmental control of information is wrecking the democratic political systems. We are rapidly approaching worldwide Fascism where Big Science, Big Business, Big Philanthropy and, especially, Big Government are all colluding for increased control over regular people. Leftist media just does what it is told by the Big 4.
And then there is the Power Behind the Throne — the MSM
No, Clyde, they just take directions from the Big 4. I’m not aware of the MSM having an original thought, ever.
“I like to think about manmade CO2 emissions as recycling CO2 that was sequestered underground in coal, oil and gas, putting CO2 back into the troposphere where it originally was. Recycling CO2 is great for C3 photosynthesis plants.”
Exactly my understanding of the importance of carbon dioxide for increasing the greening of earth in the future. Throughout the history of earth as science has discovered high concentrations of carbon sequestration from fossils of flora and fauna that is now rock of once living organisms that during events like glaciations, volcanic activities poisonous gases to massive meteors extinctions will never return to the atmosphere from rock. Fossil fuels of oil, gases, coal and of limestone and biomatter sequestered carbon releases carbon dioxide and returns the carbon to be used in flora and fauna of the present and future. All organic life was at starvation levels during the LGM and what didn’t die has taken some 12,000 years to increase the global biomass through the carbon cycle. The carbon cycle has always increased during the warming events and decreased during the cooling events of these past 12,000 years naturally and humans have been a little help by farming and animal husbandry to increase the earth’s biomass. Fossil fuels and everything else humans have done has only given a nudge to the carbon cycle by returning a minute amount of that sequestered carbon back into the environment that supports more biomass of a greener earth that is more populated by fauna than when humans first appeared before the LGM.
While nobody can foresee the future when all of the fossil fuels are depleted nor what the climate will actually be like. Fossil fuels have helped billions of people survive longer in over a century – by human innovations that wouldn’t have happened without them – to live in parts of the world that they otherwise couldn’t because of the climate.
Most proxies require some sort of calibration using modern data and assuming the same mechanisms that control the proxy now held true in the past. There are a few, however, that don’t require calibration at all (e.g., borehole temperatures), and I used to work on one: noble gas temperatures derived from groundwater (NGTs). NGTs are great on the temperature front, but their temporal resolutions is not spectacular. I seem to recall that NGTs suggest a temperature difference for the tropics between the Holocene and the Last Glacial Maximum was ~5C.
Contrary to archaeological mythology, it turns out that homo sapiens sapiens never actually lived in caves to any large extend. The “cave man” scenario never turns up anything more substantial than hunting camps and the odd disaster shelter.
One could imagine their hobos hanging out on a rock, but people had houses, towns, within sight of large cave complexes containing nothing but a few gnawed bones and typical teenager graffiti. You know, guys with big sticks and gals with huge knockers?
…but we’re absolutely sure they were all climate refugees, twice a year, every year, moving after the grazing…
This is all frightfully interesting stuff, Andy. But it’s hopelessly off narrative. And the narrative is what gets to be broadcast, printed etc.
In science at least climate is a trend over a minimum of 30 years. The alarmists were always very quick to point out that weather is not climate until more recently. Now, every nanosecond event is evidence of climate change…
“Climate change playing out in real time’
”https://www.theguardian.com/environment/2023/feb/24/early-spring-us-climate-change-record
One thing that surprised me was the apparent disappearance of Christopher Scotese’s graphs on CO2 and temperature through geologic ages.
But you can find them on the Wayback machine….
https://web.archive.org/web/20190807214029/http://www.biocab.org/Carbon_Dioxide_Geological_Timescale.html
I don’t like that graph by Scotese, with the logarithmic time scale. A logarithmic scale hides a lot of critical detail.
It’s true graphs can lie more than tell truth, but the fact that they had ‘gone’ piqued my interest more than anything else.
A lot of things are slowly going down the memory hole.
It is true that a log scale can hide things. However, it may appropriate when one considers that the temporal sample resolution decreases as one goes back in time, and transient events may be missed altogether because of the coarse sampling. And, the amplitude of the parameter being measured is smoothed by dilution and diffusion.
Thank you, Strativarius!
I searched high and low for those graphs about nine months ago.
Andy is correct about logarithmic time scales, but those graphs are the most like the graphs they used to post in older geology books.
“the IPCC does not like to discuss the correlation between CO2 and temperature during the Holocene. It destroys their hypothesis that greenhouse gases and volcanos control Earth’s climate.”
Total straw man. The IPCC does not hold that hypothesis. The reason they don’t discuss that correlation much is that CO2 changed very little over the period. They don’t expect it to have caused anything.
But the puzzling thing is that you do quote what the IPCC says, and it is nothing like that. What science has known for a century or so is that glacial changes are caused by orbital changes, and this applies also to the Holocene. And you quote the IPCC saying exactly that:
“Long-term climate changes during the Holocene are consistent with the effects of orbital forcing, modified by the persistence of the Laurentide ice sheet (which finally disappeared around 6 ky BP).” (TAR)
“Natural variations in CO2 during the past 11,000 years (Figure 3.2c [our figure 5]) have been small “
You quote the AR$, paraphrasing it as
“So significant and complex climate responses resulted from a 20-ppm change in CO2,”
But they don’t say that at all, anywhere. What they do say is:
“Such extensive data coverage provides a sound basis to evaluate the capacity of climate models to capture the response of the climate system to the orbital forcing“
“AR$”
AR$E
Corrected, no charge.
A better fix is: AR4
Nick,
As usual my point flies right over your head. This is from AR6:
Their models only include GHGs, which is why they model temperature increasing during the Neoglacial, rather than decreasing. If their models were honest, and followed what they include in the text, and properly included orbital parameters, they would get better results. If they further added in changes in meridional transport, stratospheric ozone, ocean oscillations, and solar activity changes, they would do much better. But, then they would find out the ugly truth, GHGs don’t matter much.
They emphasize the past 270 years, because then they can do what they want. It is only the acid test of the Holocene that screws them up, so they ignore it.
Their hypothesis, developed in 1960s, is very dated now. They need to update it to include what has been discovered since then.
Andy,
“As usual my point flies right over your head.”
Your point is certainly airy, and prone to change. You were talking about the Holocene (see eg your featured graph); now you only talk about post-1750. Let me remind you of what you said that I was responding to:
“the IPCC does not like to discuss the correlation between CO2 and temperature during the Holocene. It destroys their hypothesis that greenhouse gases and volcanos control Earth’s climate.”
Totally wrong, and you have no basis for it in the quotes you provide. In fact, they say the opposite. They say that CO2 varied little, and the changes were due to orbital variation. Here is AR4 TS p 58 laying it out quite explicitly:
“The Last Glacial Maximum (LGM; the last ‘ice age’ about 21,000 years ago) and the mid-Holocene (6000 years ago) were different from the current climate not because of random variability, but because of altered seasonal and global forcing linked to known differences in the Earth’s orbit“
You said:
” If their models were honest, and followed what they include in the text, and properly included orbital parameters, they would get better results. If they further added in changes in meridional transport, stratospheric ozone, ocean oscillations, and solar activity changes, they would do much better. “
You have no idea what is in the models. Of course they include orbital parameters, ozone and solar activity. They don’t specify meridional transport or ocean oscillations; those are outcomes of the modelling.
Nick,
So, if they have it all figured out and their models are correct, why can’t they model the Holocene? If their model since 1750 is correct, why doesn’t the same model, model the Holocene? See here:
Revisiting the Holocene global temperature conundrum | Nature
That is my point, and IMHO well stated in the quote you do not like:
They are ignoring the Holocene, because their models do not work over the Holocene and it belies their hindcast to 1750. Q.E.D.
You have given no evidence that models don’t work for the Holocene other than a plot from Javier’s self-published book. It doesn’t even say what the modelled temperature is of. I believe it may be global all seasons, whereas the data which is said to contradict it is NH, with proxies from the warm season. Here from Mann’s 2009 paper is a GCM result, for NH warm season (red dashes). It seems to get it right:
I’m sure others since have done it more thoroughly. Mann et al where just trying to verify borehole reults.
Beautiful, Nick. The only data on that chart, besides the ubiquitous modern instrument record tacked on at the end, is the borehole data, shown complete with error bars. However, since its rise in temperature from 2000 yrs before present doesn’t agree with the GCM outputs, Mann and the usual suspects simply write it off. As I said. just beautiful.
Nobody has much faith in borehole data. Mann et al were seeking to see if there was an identifiable bias that could make sense of it. But my point here is that their NH warm season curve does have the mid-holocene peak. I gather the existence of that is still in some doubt. The story is a lot more complicated than a single line on a graph from Javier’s book can tell us.
‘Nobody has much faith in borehole data.’
Are you trying to say is that we should only have faith in the borehole data between 9000 and 2000 years before present, because that’s when it agrees with the modeled ‘NH Warm Season SAT’? Sorry, but wouldn’t the correct inference from Mann’s graph be that nobody should have much faith in the models?
I quoted Mann’s graph because it has the relevant result of NH SAT, warm season. The borehole result is irrelevant to my argument, but it is not seasonal. What kind of average of the seasons it produces is unclear; that is something Mann is trying to work out.
“Mann et al were seeking to see if there was an identifiable bias”
That, Nick, has to be the funniest thing I’ve read this week. Congratulations.
Mann should have looked in the mirror, then he would have found the bias he was looking for
Here is some new research that you might find interesting:
https://www.nature.com/articles/s41586-022-05411-8
That’s bullshit and you know it. The model curve in that plot is from:
Liu, Z., Zhu, J., Rosenthal, Y., Zhang, X., Otto-Bliesner, B.L., Timmermann, A., Smith, R.S., Lohmann, G., Zheng, W. and Elison Timm, O., 2014. The Holocene temperature conundrum. Proceedings of the National Academy of Sciences, 111(34), pp.E3501-E3505.
That paper is peer-reviewed, as my book is. Everything in my book and its figures is fully referenced.
The quality of your comments is going down, you remind me of Stephen Mosher and his sad decay into a parody of himself.
Your book may be fully referenced, but Andy should have given the Liu reference here, not expect us to buy the Javier book to find it.
Nick, the book is free as a pdf here:
(11) (PDF) Climate of the Past, Present and Future. A scientific debate, 2nd ed. (researchgate.net)
I referenced the source of the graph, all that is required.
‘Mann et al where just trying to verify borehole results.’
Btw, models can either agree or disagree with data. Only other data can verify or refute existing data.
Borehole data does not measure temperature at a past time. To get that, you have to back-solve a diffusion equation, a notoriously chancy mathematical process. Mann et al were trying to see where that mathematics might have a bias.
‘To get that, you have to back-solve a diffusion equation, a notoriously chancy mathematical process.’
Anymore chancy, say, than attempting to numerically ‘solve’ the Navier-Stokes equations with grids that are sized orders of magnitude larger than the phenomena that transports most of the Earth’s heat from its surface?
Much more chancy. Solving The N-S equations is a major engineering activity – CFD. But the diffusion equation, forward in time, smooths out all sorts of high frequency stuff. Solving backwards inserts a whole lot of spurious HF.
Mann is a known fraud and liar. I believe nothing of importance he touches. And kicking up dust to obscure larger truths, Nick, is form of deception.
UN IPCC CliSciFi models vary wildly between themselves in all climate metrics and are demonstratively unfit to fundamentally alter mankind’s societies, economies and energy systems. Everything else is rhetoric to foist ideological biases on the Western world. The Leftist UN has used climate change to push its anti-capitalist and collectivist campaigns since day one. You know it and everybody else knows it, even those that support the goals.
Defending Mann is SO 1990s.
ps
“why doesn’t the same model, model the Holocene?”
I looked at the paper you linked. It isn’t about GCM modelling at all.
“Recent global temperature reconstructions for the current interglacial period (the Holocene, beginning 11,700 years ago) have generated contrasting trends.”
From the Figure 1 in the paper in Nature.
Preindustrial= Little Ice Age. Do you really believe the CMIP6 models, which say the HCO was colder than the Little Ice Age?
If you do, I have a bridge I will sell you in Brooklyn.
Revisiting the Holocene global temperature conundrum | Nature
Nick,
Kaufman’s paper is explicitly about the CMIP model’s mismatch in the Holocene. From the paper:
Revisiting the Holocene global temperature conundrum | Nature
A little later on:
Basically, exactly what I’ve been saying.
No, Kaufman’s paper is about doubts as to whether the proxy reconstructions really do say there was a maximum:
“From a large variety of available evidence, we find support for a relatively mild millennial-scale global thermal maximum during the mid-Holocene, but more research is needed to firmly resolve the conundrum and to advance our understanding of slow-moving climate variability.”
Give it up Nick, I already addressed that.
Gee, the science isn’t settled? However, this is all bullshit: Glaciers advanced throughout the Neo-glacial period, reaching maximum extents during the Little Ice Age. No amount of palaeoclimatological mumbo-jumbo by known liars changes this physical fact. Try just one of Steve McIntyre’s Twitter feeds dealing with Mannian and Kaufman paleo practices:
https://twitter.com/search?q=PAGES2K%20(from%3Aclimateaudit)&src=typed_query&f=live
The “scientists” can update the models until the cows come home (scientific term) but they will ALWAYS predict rapid dangerous global warming caused by manmade greenhouse emissions. Except the Russian INM model, which may get sanctioned and thrown out of CMIP7, because it is out of the narrative range (+2.5 to +4.0 degrees C.).
Models are tools for climate scaremongering — propaganda — the knowledge of every climate change variable, needed to construct a real model, does not exist.
They are climate confuser games, not models of the climate on this planet..
It looks like CO2 *did* go up by about 4% during the holocene while temps went down. So CO2 is *not* the only thermostat if it is one at all.
The fact that the models temperature projections correlate so closely to CO2 growth is telling. It is apparent that almost nothing else is considered in the models except as random, insignificant noise.
We are told that CO2 is well-mixed in the atmosphere implying that *everywhere* on the globe should be seeing approximately the same temperature growth. Yet we can see that is not true in at least the central US. That means there *must* be other thermostats that are controlling the temperature, again at least in the central US. If you look at 20 year cooling degree-day totals from samples around the globe the central US is *not* the only place seeing moderating maximum temperatures, meaning those locations are also being impacted by something else other than CO2 growth.
If the models can’t model the holocene then how can they model today? It’s obvious to even a sixth grader that something else is involved other than CO2.
‘If the models can’t model the holocene then how can they model today?’
That’s where the secret sauce comes in. Sometimes you hide the model, like Mann did when his tree ring proxy diverged from the temperature data and sometimes you ignore the data, like Mann did when the model (in Nick’s graph, above) diverged from the borehole data.
It is obvious that CO2 has nothing to do with the Earth’s temperature, since there are a multitude of examples of reverse correlation between temperature and atmospheric CO2.
But “climate science” won’t release its death grip on its CO2 fetishism, because it’s the goose that lays the golden grant funding eggs. Admit they’re wrong?! Consider the massive ego and arrogance of snake-oil salesmen like Mann for but a moment. It will never happen. New York City can be chipping away at the edge of an advancing glacier and they’ll still be spreading their “global warming/climate catastrophe by human emissions” bullshit.
“It’s obvious to even a sixth grader that something else is involved other than CO2.”
Yes. It is obvious to a sixth grader who reads what I have said, and what the IPCC is saying, that orbital variation is involved in the holocene period.
They say it is, but the models don’t get the Holocene right.
‘…what the IPCC is saying, that orbital variation is involved in the holocene period.’
And notwithstanding our CO2 emissions, orbital variation will be involved when the Earth slips into its next glaciation phase.
But orbital variation is not involved today? Then why are some places cooling instead of warming? Why is the central US cooling to stagnant? What other place on the globe is offsetting that?
You would agree that there’s more than one possible answer to that. Orbital forcing changes too slowly to have but a small effect during the course of human life.
Exactly, yet models don’t get Holocene climate variations right despite having Milankovitch forcing coded in them. Do you know why? Because CO2 sensitivity has been so pumped up that it even beats Milankovitch. It is thoroughly absurd. They constitute evidence that climate sensitivity to CO2 is lower than generally considered by models.
Why should the climate become more sensitive to CO2 during the Holocene Epoch when apparently orbital variations have always been present? It seems to me that you are arguing that whatever was controlling the climate before the Industrial Revolution has ceased to have any influence and the climate has suddenly switched from being controlled by orbital variation to being controlled by CO2, despite CO2 having been more abundant many times in the past.
Yes, I think it implies that CO2 has to have a negligible influence if anti-correlations are observed. Yet, the behavior of the various political groups is to declare that the CO2 influence dominates and requires a revolution in our economic systems.
(1) CO2 is estimated to have ranged from about 180ppm to 300ppm in the ice core period. 18ppm to 280ppm is an increase of +67%
Natural causes of climate change that warmed oceans caused CO2 outgassing. CO2 is a feedback to other natural causes of climate change
(2) CO2 is estimated to have increased from 280ppm to 420 ppm from 1850 to 2023, an increase of +50%
Manmade increase of CO2 caused some of the global warming.
CO2 is one of many natural and manmade causes of climate change.
‘Manmade increase of CO2 caused some of the global warming.’
Possibly, but neither you nor anyone else has any direct evidence to that effect and/or of its magnitude.
A +50% increase of CO2 from 1850 to 2023 had to have caused some amount of global warming because CO2 is a greenhouse gas and that’s what greenhouse gases do.
Which is easily measured in a laboratory with and without water vapor in the air.
There is no logical reason, or even a weak reason, that would explain why a +50% CO2 increase would not have impeded Earth’s ability to cool itself by some amount.
People get convicted of murders with no witnesses.
CO2 does its “work” whether we can measure it precisely or not. AGW denial gets no respect from Climate Howlers or from me.
However, that simplistic laboratory experiment doesn’t address other feedback loops.
Yes, CO2 can contribute to warming. But, the unanswered question still remains, “How much?”
If we can’t measure the CO2 impact ‘precisely,’ then it is probably negligible.
Yes. In case (1) the warming of about 6C over some millennia was caused primarily by orbital variation. CO2 provided minor feedback, probably about 1C
In case (2) there was essentially no orbital variation over that 173 years. CO2 caused a rise of about 1C, with more in the pipeline from that increase.
Nick quote: “In case (1) the warming of about 6C over some millennia was caused primarily by orbital variation. CO2 provided minor feedback, probably about 1C”.
That is patently wrong, Nick, because many NH Milankovitch Maxima (NH Great Summers) produce NO WARMING whatsoever.
If orbital cycles were that strong, and the CO2 feedback that weak, then we would expect interglacial on EVERY NH Great Summer. But we don’t. Interglacials are only successful during one-in-four or one-in-five NH GSs.
Come on Nick – explain the intermittency problem. Why to these ‘powerful’ orbital cycles only work once in a while?
Ralph
Here is the IPCC AR4 with a FAQ on the topic
“Starting with the ice ages that have come and gone in regular cycles for the past nearly three million years, there is strong evidence that these are linked to regular variations in the Earth’s orbit around the Sun, the so-called Milankovitch cycles (Figure 1). These cycles change the amount of solar radiation received at each latitude in each season (but hardly affect the global annual mean), and they can be calculated with astronomical precision. There is still some discussion about how exactly this starts and ends ice ages, but many studies suggest that the amount of summer sunshine on northern continents is crucial: if it drops below a critical value, snow from the past winter does not melt away in summer and an ice sheet starts to grow as more and more snow accumulates. Climate model simulations confirm that an Ice Age can indeed be started in this way, while simple conceptual models have been used to successfully ‘hindcast’ the onset of past glaciations based on the orbital changes. The next large reduction in northern summer insolation, similar to those that started past Ice Ages, is due to begin in 30,000 years.”
Nick.
Oh, so you resort to quoting the IPCC, which does not explain anything.
Look, Nick, there are many NH Great Summers (NH insulation maxima) which are extremely strong – way above the normal interglacial ‘threshold’ (should such a thing exist). Yet they produce no warming at all.
Why?
Likewise, there are many, many strong SH Great Summers which produce no warming whatsoever. Why do these not produce warming and interglacials? Why are interglacials a NH insolation phenomena?
You cannot explain, can you?
.
The answer, should you ever be interested in the truth, is dust on northern ice sheets (not CO2). Dust only settles on the ice sheets, just before each interglacial.
We are looking for an intermittent NH based feedback agent. Well here is that intermittent NH based feedback agent – it is dust from the Gobi Plateau. The same dust that created the Loess Plateau.
Ralph
There are multiple cycles in play. Different cycles interact to amplify and nullify each other in complex ways. This is well understood. It certainly happens in Milankovitch cycles so it is a possible, though not necessarily exclusive explanation of the different results.
Andy – all the orbital cycles are contained within the Miankovitch cycle. What other cycles do you refer to?
R
Each time any particular cycle reaches a particular point in its circuit, the other cycles are at different points and different phases than they were the last time it was at that point. Even if those things called Milankovitch Cycles were the only factors involved, their combined results would keep varying.
That is a belief-based statement, as there is no evidence that the increase of CO2 caused all the warming as you assume. That sort of assumption is improper in evidence-based science.
Makes sense to me
No empirical evidence supports atmospheric CO2 as “THE driver” OR a “contributer” to the Earth’s temperature. The notion of any temperature “effect” based on atmospheric CO2 is purely hypothetical, and dependent on the foundational assumption “all other things held equal.”
Which they have never been, are not, and will never be.
The “feedbacks” are negative, offsetting feedbacks and the ACTUAL, as opposed to hypothetical, effects of additional atmospheric CO2 cannot be distinguished from ZERO. Which is what observations support, with a multitude of examples of REVERSE CORRELATION, which plainly indicate the lack of any casual relationship.
Let’s stop asserting “facts” that are not only not in evidence, but are refuted by evidence.
Lack of evidence has never been a problem for science. No empirical evidence ever supported the existence of the aether, yet for some time every scientist believed it existed.
Without trying to compare myself to the great Sam Clemens, I would add to that the following reflection: It is quite ill-considered among scientists to believe in God, yet to believe in hypotheses for which no evidence exists is considered the most natural thing for a scientist. Quite a contradiction.
Dark Matter?
YOUR CO2 CLAIMS ARE COMPLETELY REFUTED BY LABORATORY EXPERIMENTS, SO THEY ARE CLAPTRAP.
Greenhouse gases are one of many climate change variables. If you are a greenhouse gas denier, then you are a fool.
I’ve read, quite a few years ago now, that one of the reasons apart from farmers cutting down native forests in Scotland for cultivation was a change in climate to colder and wetter around 3000BCE. The remains of these forests are buried in peat across most of the country, The same story is told about Irish forests and bogs.
When politicians say “reverse climate change” I think go back about 5000 years woud be good.
“The recent (20th century) warming needs to be considered in the light of evidence that rapid climatic changes can occur naturally in the climate.”
(SAR, p. 179).
—————-
And where has this been done?
Instead we have handwaving. Expert judgement without hard numbers.
What is the natural statistical variance of climate? Has this all been masked by artificially adjusting out annual orbital forcings and working with anomalies?
Are modern temperatures within 3 standard deviations of long term average temperatures? If so there is nothing unusual about modern temperatures. Except faulty analysis by would be climate experts.
I very much suspect that adjusting out climatology to yield anomalies has artificially hidden natural Climate Variability and given the illusion that modern temperatures are somehow unusual.
This is a good article and I added it to my list (link below) of recommended articles earlier today, but I read it at Andy May’s website first.
Honest Climate Science and Energy
Charles Rotter: Why don’t you include a link to Mr. May’s website for the article he published on February 23, that you cut and pasted here on February 2?. I think his website deserves a link here — there are lots of other good articles there too.
Climate Blog – Andy May Petrophysicist
The BEST 45 pages that will make nearly anyone well rounded on the Global Warming topic Is On Andy May’s site:
https://andymaypetrophysicist.files.wordpress.com/2021/09/happer_major_statement.pdf
Very informative and concise, thanks!
This simply means that orbital forcing (ie: the looming NH Great Winter) is much stronger than any CO2 feedbacks.
But we already knew that from the ice age record. If you look at a graph of ice age temperature VS CO2, you will note that: when CO2 is high the world cools, and when CO2 is low the world warms.
The climate would not do this, if CO2 really was a strong feedback agent. See the paper:
Modulation of Ice Ages by Dust and Albedo.
https://www.sciencedirect.com/science/article/pii/S1674987116300305
Another disproof of CO2 as a powerful feedback, is the fact that all ice ages are generated and ended by Northern Hemisphere (NH) orbital influences (Great Summers and Winters). Again, this would not happen with a global feedback like CO2. But it would happen with dust-ice-albedo as a feedback.
Why? Because all the continents are in the north, so the ice sheets are in the north, so the new CO2 deserts are in the north (the Gobi), thus the dust is in the north, and the darkened low-albedo ice sheets are in the north.
CO2 as an ice age feedback explains nothing, while dust-ice-albedo explains everything.
Ralph
“This simply means that orbital forcing (ie: the looming NH Great Winter) is much stronger than any CO2 feedbacks.”
When you dig up carbon and put CO2 directly in the air, that isn’t a feedback. It is a forcing.
And yes, over multi-millennia orbital variation forcing is strong. We knew that. But CO2 forcing is causing warming over decades, when orbital variations are very small.
‘But CO2 forcing is causing warming over decades…’
Evidence?
You won’t get any evidence from him. He doesn’t have any evidence. Nobody has that evidence.
I have no fear of being contradicted. 🙂
Firstly…
Forcing is a primary input of energy into the climate system – ie: the Sun.
Feedbacks are variable secondary inputs or outputs of energy into or out of the climate system – ie: ice sheet albedo, or perhaps (in a very minor capacity) CO2. Hansen said so.
.
Secondly…
a. If orbital forcing is so strong, as you say, then why do you bother invoking CO2 at all? It would be superfluous.
b. We know that orbital forcing is not actually very strong, because many orbital maxima (NH Great Summers) produce no temperature response whatsoever.
c. You also did not answer my question about hemispheric asymmetry. Why would a global feedback (CO2) only produce interglacials during NH orbital maxima (NH Great Summers)?
Your concentration on semantic trivia, and silence on the essentials is noted. You obviously have no rational reasoning to bring to the table.
.
What we know…
a. Orbital forcing is stronger than CO2.
b. Orbital forcing is not sufficient to generate interglacials.
c. There must exist another feedback that is stronger than CO2.
d. That strong feedback must be based in the NH.
e. That feedback must be intermittent, as it does not assists some NH Great Summers.
f. Since CO2 is global, weak, and constantly present, it cannot be CO2 modulating the ice age climate.
g. The likely culprit is dust-ice-sheet albedo.
i) Because this is NH based.
ii) Because this is 1,000 times stronger than CO2 when calculated regionally.
iii) Because this only appears just before each interglacial (ie, it is intermittent).
Ergo: the classical theory of ice age modulation is completely wrong. CO2 does NOT control the ice age climate – the likely feedback is actually ice sheet albedo.
Ralph
You don’t have your forcing and feedback concepts clear. Forcing is anything that alters the net radiative flux at the top of the atmosphere away from equilibrium, and feedback is anything that responds to that change, further altering the net flux, positive if in the same direction or negative in the opposite direction.
The climate responds mainly to obliquity changes, not to precessional changes in insolation. This has been convincingly shown by a simple frequency analysis comparison between orbital forcing and climate response.
From: Imbrie, J., Berger, A., Boyle, E.A., Clemens, S.C., Duffy, A., Howard, W.R., Kukla, G., Kutzbach, J., Martinson, D.G., McIntyre, A. and Mix, A.C., 1993. On the structure and origin of major glaciation cycles 2. The 100,000‐year cycle. Paleoceanography, 8(6), pp.699-735.
The climatic response to the precession band is tiny, ergo it is not precession. All the rest is just an ad hoc explanation for why it is precession despite it being not possible.
Orbital forcing is huge and very capable of producing the glacial cycle. Once obliquity falls below 23º there will be nothing capable of stopping the next glaciation. There’s not enough CO2 on the planet for that.
So you believe. But the ice-albedo feedback has shown to be much more feeble than anticipated, and unable to drive further summer sea ice loss in the Arctic since 2007 despite fears of an ice-albedo-feedback driven Arctic sea ice death spiral. And the reason is that surface albedo is negligible. Earth’s albedo is 90% atmospheric albedo, and surface albedo is significant where it doesn’t matter much for the climate. Dust-ice-sheet albedo suffers from the same incapacity.
Javier.
a. Greenhouse gas feedbacks do NOT come from the top of the atmosphere, they come from the troposphere. So by your own definition, CO2 is not a forcing. As Hansen said (he said the definition is muddled).
b. It is NOT obliquity that forces interglacials, it is NH Milankovitch insolation (the Seasonal Great Year). Which does of course include obliquity as a minor component.
. You cannot do a fourier analysis on a cycle that is variable (85 or 110 ky cycles) and expect a reliable answer. And anyone looking for a 100 ky cycle is misleading you, because the ice age cycle is NOT 100 ky.
. Interglacials align much more closely with NH Great Summers, than with obliquity. Besides, even if you like obliquity, many obliquity maxima do NOT produce interglacials. So you are back to square one – orbital cycles quite obviously require a feedback to succeed, and that feedback cannot be CO2. (Because CO2 is always present and by definition it is too weak – ice age warming and cooling always precedes or is indifferent to CO2 responses, much as this Holocene graph demonstrates).
c. How can you say that surface albedo is negligible? The difference between fresh snow at 0.9 albedo and dirty dust covered snow at 0.6 albedo is enormous – and can represent say 180 W/m2. Meanwhile, during the 5 ky of interglacial warming CO2 can only deliver 0.008 W/m2 per decade. Which is stronger, 180 W/m2 or 0.008 W/m2 ?
. And you seem to muddle cause and effect. Who says that shrinking Arctic sea ice is due to warming.? Rather it is shrinking sea ice that caused recent warming (plus the reducing springtime NH snow extent). Winter snows are reducing more quickly, possibly due to industrial contamination. See Pinter et al, who demonstrated that Alpine glacial retreat was due to Industrial Revolution soot contamination, dating back 150 years or so.
. But the Dark Snow Project, that set out to quantify these effects, had their funding cancelled because they did not mention Co2 in their first report.
The Dark Snow Project.
https://web.archive.org/web/20150108131218/http://darksnow.org
Even their website has expired. But look at the extent of the industrial soot contamination on Arctic snow and ice. Are you really saying that this will have no effect on insolation absorption and melting? Really? That albedo is down to 0.2, with a feedback effect of 450 W/m2 during a NH Great Summer, or about 300 W/m2 nowadays.
Ralph
You did not understand what I said. If it changes the net flux at the top of the atmosphere and a forcing does not cause it, then it is a forcing by definition regardless of where it takes place. Land use change is a forcing because it modifies the flux at the top of the atmosphere (albedo) and is not caused by another forcing.
You have not understood what Milutin Milankovic said when he was talking about the caloric half-year. Perhaps you should go back to reading him. Insolation is a second-order factor and its lack of climatic effect by itself demonstrates it.
Because the atmosphere attenuates surface albedo by a factor of three. Study the issue. It is known.
Not me. I haven’t said that. But it is reasonable to think that the warming is not helping sea ice.
Says the person that mistakes the effect, dust, with the cause, the glacial cycle.
Javier – you have comprehensively lost the argument, because you will not answer the fundamental questions raised by the ice age cycle.
I repeat.
a. Why are interglacials NH based, only reacting to NH orbital cycles?
b. Why are interglacials intermittent in response to NH orbital cycles?
c. If CO2 is demonstrably too weak to be the feedback agent, then what is the true feedback agent?
Your failure to answer these basic questions means you know nothing about ice age control and modulation.
Plus:
a. CO2 does NOT change flux at the top of the atmosphere. It changes the DLR flux in the troposphere, starting from just 500 ft in altitude. Thus CO2 cannot be a forcing agent – it is by your own definition a feedback.
b. You brandish the caloric half year as if it is some paleoclimatic trump card, produced from under the table. But if you knew anything about insolation absorption you would realise that the caloric half year is irrelevant.
. With insolation absorption by dusty-ice albedo, it is the solar altitude that is the governing factor, not the caloric half year. Dust on ice can only be effective above a certain solar angle, so much of the spring and autumn insolation is irrelevant – it is simply reflected back into space.
. This is the reason why the otherwise weak obliquity effect can assist in interglacial warming – it is because it can raise the solar angle by 2.5 degrees, and thus lengthen the effective insolation-day and the effective insolation-season. You might call that a net caloric effect, but it has nothing to do with the caloric half year you are talking about.
c. Yes, we know that the atmosphere attenuates insolation. But the insolation absorption figures I gave previously take that into account. So again I ask you, what will have the greater melting effect:
. i). A 180 W/m2 increase in direct insolation absorption, measured regionally across the northern ice sheets (at 65 degree latitude).
. ii). A 0.008 W/m2 increase in DLR feedbacks per decade, by CO2 when measured globally.
What is your answer. Which will have the greater effect 180 W/m2 or 0.008 W/m2 ??
Ralph
Nor is it unusual to realize that the piles of snow most covered in dark debris are the last to melt come Spring.
Thick dirt/coal/debris layers on snow are opaque to sunlight, blocks light reaching beyond fractions of a millimeter into the ice and insulative from warm air.
ATheok (piles of snow)
Because those thickly covered piles have passed the insulation threshold, which the northern ice sheets never do.
The balance between insolation absorption and insulation is well known, and you would know this if you read the paper.
Ralph
And, rocks and dust typically have low thermal conductivity. An interesting phenomenon often observed on alpine glaciers is a pebble-boulder size rock sitting on an ice pedastal. While the rock has warmed on the surface, the heat stays there. The ice adjacent to the rock melts, except immediately underneath it.
Andy, great article on the importance of the Holocene Paleoclimate dataset.
CO2 does move opposite from global temperatures. CO2 also moves opposite from NH temperatures and Greenland ice core temperature anomalies.
But CO2 does correlate well with Antarctic ice core temperature anomalies over the Holocene. Perhaps SH processes and Southern local insolation play more of a key role in controlling underlying CO2 trends than given credit for.
Good point Renee. Antarctic temperatures do not correlate well with Northern Hemisphere temperatures. This whole “global average temperature” idea is total nonsense. Until we move beyond it and consider regional temperature variations, we will never understand climate change.
How can we move beyond it? It is the only thing the climate alarmists have to try to scare the public with.
The only thing that will change the equation in people’s minds seems to be if it continues to cool while CO2 continues to increase. Otherwise, we are at the mercy of the climate change propaganda machine, talking (erroneously) about how we are experiencing the highest average temperatures in human history today because of increased CO2.
Natural CO2 changes have been found to track Southern Ocean temperature changes since:
Bacastow, R.B., 1976. Modulation of atmospheric carbon dioxide by the Southern Oscillation. Nature, 261(5556), pp.116-118.
That figure of yours would support that is the case for most of the Holocene.
Javier. Yes, because CO2 is a consequence of sea temps, not a cause of it. So of course CO2 follows the temp of the large oceans.
But if CO2 is only a minor player in climate feedbacks, we need to find another (much stronger) feedback. And that feedback is dusty-ice-sheet albedo.
R
This post is a very long term view of the attribution problem and natural variation. AR4 SPM fig 4 and Lindzen took a ‘century’ view concerning the warming from ~1920-1945 and ~1976-2000. They are essentially indistinguishable. The former period could not have been mainly GHE—not enough change in CO2. Yet the IPCC attributes the latter period exclusively to GHE. Natural variation did not stop in 1975. Tuned parameters to best hindcast drags natural variation into the misattributed models, which causes them to observationally run hot by about 2x. There is no way to fix this fatal flaw.
If you are simulating observations, and base your fit of the past based on only half of the actual parameters, simply because you were not aware of some of the parameters….your extrapolation into the future can be significantly in error, maybe by double….
This is one of the reasons climate scientist have gone to global circulation models instead of parameterization models, believing that using fundamental Navier Stokes equations must be more accurate.
But certain elements of their models can only be parameterized, such as cloud formation, optical depth, size of convection cells, etc., there are actually hundreds of parameters either input to GCM’s or hard programmed into the code ….It is a really obvious case of computer programming geeks overselling gigaflops for continuing employment purposes. Just the number of models alone indicate these career seekers exist in many institutions in many countries.
As one of the UN IPCC CMIP modelers said: We tune the model to get an ECS that looks about right.
Figure 1 glaringly omits the recent part of the Holocene with CO2 being increased from below 300 to over 400 PPMV, and a notably correlating sharp and significant temperature increase.
don,
The past 70 years or so of increasing CO2, is barely one point in the Holocene proxy data, which has a temporal resolution of roughly +-50 years. Besides, correlation is not causation.
Figure 1 is about the Holocene, not the past century. Climate change causes don’t necessarily have to be the same, even though we are asked to believe natural climate change got canceled around 1950.
Yet the equally “sharp and significant temperature increase” over the same period length in the early 20th Century was not associated with a CO2 increase. How many times must one have to hear “correlation is not causation” before it sinks in, Don?
There was CO2 change from the beginning of the Industrial Revolution to the WWII global temperature bump. Multidecadal oscillations also contributed to that temperature rise, and the slight decrease of global temperature from the WWII peak to the mid 1970s, the rapid temperature rise from the mid 1970s to shortly after 2000, and the slowdown of temperature rise after shortly after 2000. Also, the temperature rise since the late 1970s is greater than the temperature rise that culminated with the WWII peak. https://woodfortrees.org/graph/hadcrut4gl
CO2 cannot cause temperature increase from IR interaction at STP.
Figure 2, why does the Arctic not warm with the Northern Hemisphere 7000-4000 BC?
Northern Hemisphere insolation peaked about 10,000 years ago, and obliquity about 9,000 years ago. The high northern latitudes are the great losers in the orbital changes for the past 10,000 years. Add to that, the melting of the northern ice sheets was completed about 7,000 years ago, removing a big cooling factor outside the Arctic circle, but not inside.
https://wattsupwiththat.com/2022/04/11/new-study-arctic-was-much-warmer-6000-years-ago-90-of-glaciers-ice-caps-smaller-than-present-or-absent/
The Arctic does appear to be slightly odd.
Very good.
Synopsis: Climate models fail to agree with observations, again.
“Global average surface temperature (GAST) is almost a meaningless number”
There’s no almost about it. It’s meaningless because of the principle of Intensive Properties. Taking readings from all over and averaging them together is a Bozo No-No.
And then you have proxies. Ho boy. Vastly different things, supposedly showing temperature, from vastly different regions, averaged together, is worse than meaningless.
Does anyone here live at the “Global Average Temperature”?
The truly sad thing is that we’ve had the data available to calculate enthalpy (pressure, elevation, humidity, etc) since the 80’s. We could have 40 years worth of actual measurement of the heat in the atmosphere but climate science is stuck in the dark ages (and I mean *the* Dark Ages).
There are even enough measuring stations recording short interval temperature data that we could be using degree-day values using integration of the temperature curve over the past 20-30 years which, again, would be giving us a much better proxy for what is going on around the globe. But again, climate science remains stuck in the Dark Ages.