Guest Post By Renee Hannon
This post evaluates the relationship of global CO2 with regional temperature trends during the Holocene interglacial period. Ice core records show that CO2 is strongly coupled with local Antarctic temperature and slightly lags temperature over the past 800,000 years (Luthi, 2008). Whereas the emphasis has been on CO2 and temperature lags/leads, this study focuses on Holocene millennium trends in different latitude-bounded regions.
The Contrarian Antarctic
The Holocene is fortunate to have hundreds of proxy records analyzed by Marcott, 2013, and more recently Kaufman, 2020, to establish regional and global temperature trends. The Holocene interglacial occurs approximately during the past 11,000 years. In general, global temperature trends from proxy data show a Holocene Climatic Optimum (HCO) around 6000 to 8000 years ago and a subsequent cooling trend, the Neoglacial period, culminating in the Little Ice Age (LIA). The global mean temperature is comprised of regional trends that tend to have a concave down appearance during the Holocene shown in Figure 1a.
The exception is the Antarctic shown in red which has a concave up shape. The Antarctic reached an early Holocene Climatic Optimum between 9000 to 11000 years ago. While global and most regional temperatures were warming, Antarctic cooled to a minimum around 8000 years ago. While global and other regions show progressive cooling during the Neoglacial, the Antarctic was flat and erratic. This contrary Antarctic temperature behavior during the Holocene has also been noted by Andy May here.
Greenland and Antarctic ice core temperature anomalies derived from deuterium and/or oxygen isotopes and global proxy temperature means are shown in Figure 1b. Ice cores have high resolution over long periods of time making them a key proxy dataset. These data show similar trends to the regional compilation. However, temperature ranges tend to be larger at individual proxy sites. Smoothing of paleoclimate proxy data occurs due to averaging of multiple data types together which removes local temperature variability (Kaufman, 2023).
It’s not surprising that Antarctic temperature trends behave differently due to its unique environment. Antarctica is a continent surrounded by the Southern Ocean with a mean annual temperature of the interior between -50 to -60 deg C. Most of Antarctica is covered by a permanent ice sheet averaging 2 km in thickness. Sparse proxy data from Antarctica is predominantly from ice cores and a few marine sediments. These data comprise temperature trends in the 90oS-60oS latitude region which represent less than 10% of Earth’s surface area.
CO2 is Uniquely Synchronous with Antarctic Temperatures
CO2 gas trapped in ice bubbles show synchronous trends with local Antarctic temperature anomalies during glacial and interglacial periods over the past 800,000 years. CO2 ranges from lows of 180 ppm during glacial periods to highs of near 300 ppm during interglacial periods. Figure 2a shows the linear regression of CO2 and temperature from the EPICA Dome C ice core over the past 60,000 years that includes the Holocene interglacial and last glacial maximum. The squared regression (R2) of 0.9 is very impressive. One interesting curiosity is the Holocene interglacial period where the slope tends to flatten out and R2 decreases substantially to 0.3.
Despite the lower correlation factor for the Holocene interglacial, Figure 1a above shows that CO2 displays concave up trends like Antarctic temperature trends. CO2 reaches an early Holocene high near 275 ppm around 11,000 years ago after deglaciation. CO2 then slowly decreases by 10-15 ppm to a Holocene minimum of 260 ppm about 8000 years ago. And then, CO2 gradually increases up to 290 ppm during the Neoglacial cooling period. To note, these CO2 values are muted or smoothed due to gas trapping processes in ice and do not reflect instrumental values (Joos, 2008).
Correlation plots of Holocene CO2 versus temperature anomalies from high resolution regional proxy temperatures are shown in Figures 2b-d. They are much different than the 60,000-year Antarctic CO2 relationship in Figure 2a. The Arctic and the Northern Hemisphere regions (2c) show an inverse relationship with CO2, especially during the Neoglacial period. The tropical region (2d) shows large scatter with no statistically valid trend detected. The Southern Hemisphere, not shown, also has a low correlation with CO2. No other multi-proxy region or latitude temperature trends show a strong positive correlation with CO2 during the Holocene like the Antarctic does.
Authors have noted that CO2 has a different trend compared to global and Northern Hemisphere temperature trends. Vinos, 2022, concludes that CO2 runs opposite to global temperature trends for most of the Holocene. This CO2 asynchronous behavior and/or lack of correlation to temperature seems to be true for most regions, roughly 90% of the Earth’s surface area.
Climate Models Dominated by CO2 Forcing
Climate models fail to match global Holocene proxy temperatures known as the Holocene temperature conundrum (Liu, 2014). Models basically show a gradual increase in temperatures throughout the entire Holocene as shown in Figure 3a. While temperature proxy data shows a Holocene Climatic Optimum of 0.5 deg C around 6000-8000 years ago that climate models simply do not reproduce.
Holocene global proxy temperature trends show an inverse correlation with CO2 as plotted in Figure 3b. There are two distinct inverse trends separated by the HCO. During the Neoglacial period, proxy temperatures and CO2 show a strong negative correlation with an R2 of 0.8. Basically, as CO2 increases then global temperatures become cooler.
Temperatures from model simulations are typically controlled by changes in greenhouse gases, insolation, ice sheets, and freshwater fluxes, to name a few. Modeled temperature profiles parallel the global CO2 trend with a strong R2 of 0.7 confirming CO2 is a major model control knob. Additionally, modeled Holocene temperatures tend to resemble the contrarian Antarctic temperature trends (compare Figures 1a and 3a).
Scientists have begun to investigate the effect and possible dominance of forcings other than CO2. Zhang, 2022, modeled the effect of seasonal insolation influence and found better matches to proxy data when combining insolation with ice sheet forcing, although still not perfect. Thompson, 2022, showed that more vegetation influence in the Northern Hemisphere helps models simulate a Holocene Climatic Optimum evident in proxy data. The close relationship between CO2 and Antarctic temperature suggests that millennial variations are strongly influenced by Southern Ocean processes. Only when past forcings and the timing of their dominance are more accurately incorporated into climate simulations will models be able to predict future climate change.
Observations
Climate change is routinely claimed to be largely controlled by greenhouse gases, especially CO2. This was concluded, in part, by the strong relationship between CO2 from Antarctic ice core bubbles and local Antarctic temperature trends. While CO2 mimics Antarctic temperatures very well, ninety percent of Earth’s surface temperature trends do not demonstrate a positive correlation to CO2 during the Holocene. Arctic and Northern Hemisphere temperatures become cooler during increasing CO2 levels. Tropical proxy temperatures don’t seem to be influenced by CO2.
Model simulated temperatures which are strongly influenced by CO2 do not accurately history match Holocene global proxy temperatures and tend to largely reflect Antarctic trends. The fact that CO2 correlates well to Holocene temperatures for only the Antarctic, or <10% of our planet’s surface, yet CO2 is considered as the dominant influence on climate change is a scientific dilemma.
Download the bibliography here.
The CO2/temperature correlation is cherry picked, but warming is not a bad thing, anyway. The LIA was a period of plague, famine, and war.
Why do we need to keep doing a deep technical dive into the weeds wrt everything climate related – the amount of CO2 that could be removed from the atmosphere, even if net zero could be achieved is so tiny ( something like 1 one hundredth of 1%) that it wouldn’t change the composition of the atmosphere one bit – so if we are not changing the atmosphere how is that affecting the climate – it’s not so this is all wasted effort and money
COVID, for a short while, served to amplify the scare-mongering of CO2, similar to the Roman Catholic Church using heaven/hell scare-mongering and the Holy Cross to castigate/subjugate people and get them to build huge Cathedrals, as monuments to the glory of the All-Knowing Church, similar to all those fauna-destroying wind turbines in the North Sea.
With COVID now having the same impact as a cold or a flue, the CO2 monkey has to be blown up into King Kong, by the “we own the science” IPCC and its government-subsidized mass MEDIA
The net effect is a huge subsidy-chasing game by the already-rich people with lucrative tax shelters, at the expense of the already screwed over suckers, the so-called “little people”
These rich folks, and obsequious hangers on, have dug their way to a huge vault and do not want the vault closed or moved
Yes, exaggeration is the main tool in climate cultists’ toolset.
“Dilemma”, indeed. LOL.
“yet CO2 is considered as the dominant influence on climate change”
CO2 is not considered to be a dominant influence on the climate change of past millenia. The reason is that no-one was releasing it on a large scale.
The warming, and subsequent cooling at the end of last glaciation is universally considered to be due to orbital changes. Insofar as CO2 moves in concert, that is due to warming effect on solubility (which in turn creates a small feedback).
None of this affects the basic issue that if you do burn a lot of mined C, which has never happened before, it will cause a lot of warming.
It certainly has caused a shitload of exaggeration.
Several metric shit tonnes from Nick alone
His employers are getting their money’s worth.
Oh yeah.
Would anyone hire him?
Hasn’t happened yet.
It’s in the pipeline.
I thought it was hiding in the deep oceans?
The warming, and subsequent cooling at the end of last glaciation is universally considered to be due to orbital changes
Nick,
You are correct that orbital changes are considered a key forcing for deglaciation and eventual glaciation. However, this post is about the Holocene interglacial period. Lui, 2014, discusses that simulations show a long-term warming trend during the Holocene interglacial under the dominant forcing of increasing greenhouse gas concentrations and retreating ice sheets and only a minor influence of insolation.
Curiously (for PNAS) Liu et al don’t show what their GHG forcings were. But they do cite the review paper of Wanner et al 2008, which shows small change in CO2 from 265 to 280, and a relatively larger change in CH4 from about 600 to 700 ppb. Neither would be expected to have much effect; the real conundrum is why they didn’t show more response to orbital changes.
the real conundrum is why they (CO2 and CH4) didn’t show more response to orbital changes
Instrumental CO2 is smoothed due to gas diffusion during the firn to ice transition. The 265 ppm to 280 ppm in ice cores is significantly underestimated compared to modern gas fluctuations as demonstrated by Joos, 2008.
Fig. 8. Attenuation of atmospheric greenhouse gas variations (black) during the enclosure process of air into firn and ice as modeled with a firn diffusion and enclosure model. The attenuated signals are calculated for present (upper blue) and Last Glacial Maximum conditions (lower blue). The reference attenuation used in the text is calculated as the maximum of the mean attenuated signal from both climate extremes (red). The atmospheric concentrations (black solid lines) of CO2 (Left) and CH4 (Right) are prescribed according to data until the year 2000. The atmospheric CO2 decrease due to carbon uptake by the ocean and land biosphere is calculated with the Bern Carbon Cycle model. Atmospheric CH4 is assumed to decrease instantaneously to the preindustrial concentration.
“The 265 ppm to 280 ppm in ice cores is significantly underestimated compared to modern gas fluctuations as demonstrated by Joos, 2008.”
He says the fluctuations are underestimated. But Joos’ estimates and range are the same:
Joos nicely hid figure 8 as a supporting information figure. Unfortunately, he did not deconvolve the ice core CO2 data for his analysis.
Numerous articles about Antarctic ice core temperature and CO2 concentration relationships have stated very clearly that CO2 peaks considerably lag temperature peaks, often by 800 to 900 years. Temperatures are already trending strongly down while CO2 continues to increase for hundreds of years. Some of these articles, and others that did not concentrate so narrowly on Antarctic ice cores, say the same relationship has been observed in many other proxies. CO2 concentration changes lag temperature changes, by at least as much as 2500 years in some cases.
This article doesn’t mention any of that nor say anything about reasons for the reinterpretation of data. I don’t have any background beyond what I’ve read in WUWT and other internet sources so no way to independently conclude whether this article or those others are in error but the ignoring of history here seems too much like the alarmist narrative that refuse to acknowledge conflicting evidence.
Correct. But that doesn’t stop Nick Stokes trying to have his cake and eat it.
Just re-read what he wrote above:
” Insofar as CO2 moves in concert, that is due to warming effect on solubility (which in turn creates a small feedback).
None of this affects the basic issue that if you do burn a lot of mined C, which has never happened before, it will cause a lot of warming.”
Self-contradiction?
It is correct that this report does not agree with many other reports on the same issue.
I don’t see that what Nick wrote has any relevance to my questions.
Why is this report so different than many others about the paleo proxie relationships of atmospheric CO2 concentrations and surface temperature? Is there a reason other than ‘lets not push the alarmists too hard. Make nice and almost agree with them’?
Michael hart
I noticed the same contradiction when I read NS’s post.
They have a host of problems. Essentially, orbital forcing is only significant in small parts of the planet and/or at certain times of the year. A large ice-albedo feedback is needed to get models to reproduce the glacial cycle. However, there is no indication that the ice-albedo feedback is big. Surface albedo is only a small part of planetary albedo. Additionally, we have seen that despite the large loss of Arctic sea ice in the 1995-2012 period, no ice-albedo feedback is being observed despite fears of an Arctic death spiral. Summer Arctic sea ice extent has been stable for the past 15 years, without a significant trend.
So, we know what causes the glacial cycle to tick, but we don’t know how. The Winter Gatekeeper hypothesis I recently proposed explains it through changes to the poleward transport of heat and moisture induced by changes in the summer temperature gradient caused by changes in the summer insolation gradient produced by the change in obliquity. Who knows, I might be right.
Great point Javier. This absurd focus on global yearly averages hides the real impact of seasonal atmospheric circulation and insolation changes. Seasonal and hemispheric variations matter. All yearly global averages do is hide what mother nature is doing.
The very fact that the earth is a sphere makes global averages suspect. Too many factors vary by latitude to have them subsumed within a smoothing average. The very fact that models need “better resolution” should be a clue to the fact that huge, global averages are suspect.
“Too many factors vary by latitude”
For the umpteenth time, that is why they average anomalies.
Non-responsive to the comment. Again.
Javier and Andy,
This is an interesting article that evaluates different forcings, especially seasonal insolation, see figure 4. The poleward transport mechanism is a great addition to help explain the process. I agree global annual averages are not very useful.
https://doi.org/10.1038/s41467-022-33107-0
A throwaway claim without evidence.
This is speculative rubbish. It only occurs in climate models, not the real world.
Doubling CO2 from 285ppm will add enough atmospheric mass to increase surface temperature by 0.006C.
We can observe today that the ocean north of PNG has warmed above 30C. Then convection sets in to pull it back to less than 30C:
https://earth.nullschool.net/#2023/05/24/0000Z/ocean/isobaric/1000hPa/overlay=sea_surface_temp/orthographic=-220.43,8.08,454/loc=132.681,13.514
This is how the atmosphere works. The energy balance is completely controlled by temperature regiulating processes. The top end of 30C limited by convective instability. The bottom end of -1.7C by formation of sea ice. The average close to the numeric mean of the two extremes.
Hmmm….. .006 C increase from 285 to 570 ppm CO2. ?
It’s not hard to do a lot better than some WAG of .006
Run 285 ppm on Modtran, UChicago version. Save as background case. Fix relative humidity, change CO2 to 570 ppm, fool around with ground temp (offset) around 1 degree. I matched the background case at .92 C (mid latitude summer with some cloud). Its a reasonable number a fair bit less than IPCC 2xCO2 numbers.
You are taking Modtran as an authority. Next thing you know, you’ll be taking the IPCC as an authority.
Modtran is a model.
IPCC models are misused, therefor all models are crap.
You reason like a climate scientist.
Climate models are wrong, not misused.
Climate models have a usefulness, it’s just that the politicians running the show are misusing them.
Your rejection of all models is highly unscientific.
Modtran was developed for atmospheric correction of multispectral and IR imaging sensors. If it didn’t work properly it would be visually evident.
So it wasn’t developed as a climate model but is sort of used as one.
A grand total of nobody uses Modtran as a climate model.
Modtran is used to calculate the transparency of the atmosphere to certain frequencies. Nothing more, nothing less.
The numbers calculated by it are used as an input to climate models. Along with dozens of other things.
My initial comment was to DMacKenzie:
He claimed that Modtran calculation for doubling CO2 gave him a 0.92 C temperature increase.
Most people here think that CO2 is not a control knob for temperature.
Taking Modtran beyond its initial design parameters for atmospheric transparency.
There is no definitive proof that CO2 increases atmospheric temperatures.
Part of the development was for IR missiles.
The ocean surface cannot sustain a temperature above 30C. That is what limits heat into Earth’s system.
This fact is observable every day somewhere on the planet. Right now you can see the process in operation north of PNG. Ocean surface exceeds 30C; convection kicks. In this case in overdrive:
https://earth.nullschool.net/#current/ocean/surface/level/overlay=sea_surface_temp/orthographic=-222.87,2.25,373/loc=131.291,12.977
Modern is radiative model and gives zero insight into the convective power than causes Earth’s energy balance. No more energy can get in once the open ocean surface nudges above 30C. BANG – convection kicks in to dramatically reduce thermalisation of solar EMR and shift local surface heat to cooler regions.
During high solar activity, there will be more sea water evaporation and more cloud formation, which reflects sunlight, cools the earth, until high solar activity subsides.
A new equilibrium may be established.
6mK increase in air temperature is totally unmeasurable.
Now all you need to factor in is the evaporative cooling from increased DWIR and you’ll come very close to Rick’s number.
That still assumes a “static” atmosphere without feedbacks. The real world feedbacks will reduce that hypothetical 1 degree to something indistinguishable from zero.
Which is what observations support. Way too many instances of negative correlation to assume CO2 has a temperature effect.
Prove it. Oh, the atmosphere is too large and complex to build a physical model in….a large geodesic dome and add CO2? ….why no warming from 1940 to 1980 while CO2 went up 15%?….and the recent pause in warming while CO2 continues up?
Why no runaway greenhouse effect in the past when CO2 in the atmosphere measured 7,000ppm (as compared with 420ppm today)?
If there is no runaway greenhouse effect at 7,000ppm of CO2 in the atmosphere, then there won’t be a runaway greenhouse effect from 420ppm, either.
Does everybody see how ridiculous these climate alarmist claims about CO2 are?
You are right but the left’s useful idiots are not called useful idiots for nothing.
The mere fact that temperatures have never tracked CO2 levels doesn’t matter. After all, models trump reality.
That is not the issue. The issue is that the CO2 hypothesis has been developed to explain the warming that has taken place since 1976, because before then there was mid-20th-century cooling, and before then early 20th-century warming, and nobody knows what caused them because the 1945-1975 cooling took place when forcings were positive and the warming observed in the 1920-1945 period is too much for the known forcings.
Known forcings cannot explain the LIA. Between 1100 and 1500, when most of the cooling took place, CO2 did not change. Between 1458 and 1765 there were no significant volcanic eruptions. That’s 300 years. Most of the LIA had very low volcanic forcing by Holocene standards, yet it is the coldest period in the Holocene by far. Solar forcing has been deemed insignificant. The result is that scientists don’t know what caused the LIA.
Then we have the issue of the Holocene temperature conundrum covered by Renee.
So it turns out that the CO2 hypothesis and associated models can only explain 50 years of the past 11,700. And in doing so they render 11,650 years of climate change unexplainable. This is the mark of a failed theory. It would have been ditched long ago if it wasn’t for the strong political support. Many paleoclimatologists are very unhappy with it.
We don’t know that. Paleoclimatic evidence does not support it.
That should read
the CO2 hypothesis and associated models can only PARTIALLY explain 50 years of the past 11,700
The CO2 hypothesis does explain warming since 1976, but it does so for the wrong reasons. Explaining something does not mean that the explanation is correct.
The greatest ‘sin’ in science is to be right for the wrong reason.
And then, only with extremely generous assumptions.
“The issue is that the CO2 hypothesis has been developed to explain the warming that has taken place since 1976″
It was developed by Arrhenius in 1896.
You’re funny, Nick. You know what he means.
Nick’s goal is distraction, not enlightenment.
Arrhenius also proposed that CO2 caused the Pleistocene glaciations. But that was refuted by Hays, Imbrie, and Shackleton in 1976. Then it was thoroughly rejected by the scientific community until it was revived, for political reasons, in the 1980s.
Basically, the CO2 hypothesis and the Milankovitch hypothesis constantly traded places over the past century. CO2 dominated until the world started to cool in the 1940s, as CO2 increased dramatically. In the 1960s and 1970s, ocean floor cores showed that Milankovitch was correct (Vinos, 2022, Climate of the past, present, and future, page 140)
So, like Karl Marx, the CO2 afficionados changed their theory and said CO2 was necessary to amplify the Milankovitch changes. Obviously, temperature changes will cause CO2 to change, due to the temperature dependence of ocean CO2 absorption, but they could pretend it was the other way around, and they did.
Thus, began what we see today. All new evidence shows that nature causes climate change, yet whatever is discovered is twisted so that CO2 is the “control knob.” CO2 is the grassy knoll theory of climate change. A picture of the Kennedy assassination “grassy knoll” is attached.
No, CO2 is the lone Oswald theory.
Ask RFK, jr on the broad daylight murder of his uncke JFK :
https//www.foxnews.com/video/6327062025112
“So, like Karl Marx, the CO2 afficionados changed their theory and said CO2 was necessary to amplify the Milankovitch changes.”
As usual, no support quoted, and it just isn’t true. All agree that CO2 provides a minor positive feedback, but is in no way necessary.
Arrhenius investigated the possibility that CO2 was involved in glaciations, but gave no conclusive finding.
And you provide no support for the claim that it isn’t true. You are something else, Stokes!
Andy could quote some afficionado who did what he claims. I can’t prove a negative.
If this is true, why are you and so many pushing economic upheaval by reducing CO2? If CO2 is a minor feedback, then what is the MAJOR feedback and why are we not in a hurry to reduce it?
So many alarmist views are illogical.
And said to be wrong by Angstrom around 1900.
Angstrom was refuted.
The greenhouse gas effect theory and the enhanced CO2 effect hypothesis should not be confused.
In the first, an increase in a greenhouse gas produces an increase in atmospheric opacity leading to surface warming through a reduction in outgoing longwave radiation.
In the second, that initial greenhouse gas warming is enhanced and multiplied several times by feedback factors that react to the initial warming, not the greenhouse gas. This hypothesis makes the climate overly sensitive to warming (or cooling) by any cause, as the initial change in temperature gets multiplied.
The first is correct but doesn’t tell us how much warming is produced since that depends on how the climate system reacts.
The second is wrong.
In the second half of the 19th century, scientists were trying to explain the recently discovered glaciations. The idea was the Earth had been warmer in the distant past and slowly cooled, so glaciations were a big surprise. Scientists at the time did not think the climate was changing appreciably in their days. Arrhenius was trying to explain glaciations through the greenhouse effect theory but he was sorely beaten by Milankovitch’s orbital theory in 1976, the year global warming started.
Although the enhanced CO2 effect hypothesis is rooted in the greenhouse gas theory, it was developed starting in the 1960s with the first climate models, adding layer upon layer of feedback amplification to get it to reproduce the fast warming observed between 1976 and 1997.
Apparently, many climate scientists aren’t smart enough to understand that a stable system, like climate, cannot be dominated by positive feedback factors. It must be dominated by negative feedback factors to be sufficiently stable.
The enhanced CO2 effect hypothesis only explains warming since 1976 (for the wrong causes). It cannot explain any other climate change. As such it is just an ad hoc hypothesis without scientific value.
“Although the enhanced CO2 effect hypothesis is rooted in the greenhouse gas theory, it was developed starting in the 1960s with the first climate models”
No, Arrhenius had water vapor feedback, which doubled the effect. In fact, his 1906 paper explicitly set out the components; a doubling of CO2 would cause 1.6°C warming directly, and 3.9°C after allowing for water vapor creation.
And he had little tiny clouds in his apparatus to simulate albedo changes.
H2O can not cause temperature feedback because H2O contains LATENT HEAT which is not measurable by temperature. The whole water feedback scenario causing a temperature rise at the surface/atmosphere boundary is bogus. Any radiation from vapor condensing at altitude should be absorbed by well mixed CO2 at altitude.
“Apparently, many climate scientists aren’t smart enough to understand that a stable system, like climate, cannot be dominated by positive feedback factors. It must be dominated by negative feedback factors to be sufficiently stable.”
Yes, the Earth’s climate has had no runaway greenhouse effect in all its history, and CO2 concentrations in the atmosphere were much greater in the past than now, yet still no runaway greenhouse effect.
Obviously (although not apparently to some) the Earth’s climate is dominated by negative feedbacks.
The facts are we do not know if after feedbacks, CO2 is net warming or net cooling the Earth’s climate.
But Climate Change Alarmists insist we are on the brink of the world overheating because of CO2. Their claims are not based in reality.
Any real scientist who is paying attention would know the facts don’t support this.
Nail, meet hammer!
That was Dr. Greta Thunberg’s granpa, right?
She was belatedly nominated for a Doctorate in Theology by Helsinki.
Finnish humor, anyone?
No.
Alexandrian astronomer and mathematician Ptolemy constructed a solar system model in his Almagest and Planetary Hypotheses in 150 CE. It predicted planetary motions correctly and was 100% wrong.
A simple laboratory experiment that ignored all the possible and probable negative feedback loops that moderate the ability of CO2 to absorb IR.
“Known forcings cannot explain the LIA. Between 1100 and 1500, when most of the cooling took place, CO2 did not change. Between 1458 and 1765 there were no significant volcanic eruptions. That’s 300 years. Most of the LIA had very low volcanic forcing by Holocene standards, yet it is the coldest period in the Holocene by far.”
That would seem to blow up Burl Henry’s theory about SO2 and temperatures. What about it, Burl? No significant volcanic activity, which you claim is what causes cooling, yet the Earth experienced the Little Ice Age during that time.
ISTR Burl managed to get himself banned recently, tough to do on WUWT.
I don’t think it was Burl who got banned.
“So it turns out that the CO2 hypothesis and associated models can only explain 50 years of the past 11,700.”
More than 50. But yes, the CO2 hypothesis is that more CO2 in the air causes warming. If there isn’t more CO2, it won’t cause warming. That is not the fault of the theory.
There is a theory that eating arsenic will kill you. Most people die without eating arsenic. But the theory still holds.
“And in doing so they render 11,650 years of climate change unexplainable.”
No, it just says CO2 isn’t the explanation. You have to look elsewhere.
The hypothesis also says less CO2 in the air causes cooling. The problem is that changes in CO2 and changes in temperature only fit since 1976 and during the Pleistocene. And we know Pleistocene changes were due to orbital changes, not to CO2 changes. So the hypothesis only explains 50 years.
Take a look at Figure 2D in:
Westerhold, T., Marwan, N., Drury, A.J., Liebrand, D., Agnini, C., Anagnostou, E., Barnet, J.S., Bohaty, S.M., De Vleeschouwer, D., Florindo, F. and Frederichs, T., 2020. An astronomically dated record of Earth’s climate and its predictability over the last 66 million years. Science, 369(6509), pp.1383-1387.
If temperature depended on CO2 the scatterplot should show a diagonal. What it shows is either CO2 changing or temperature changing alone, for millions of years.
Only one possible conclusion. CO2 has a small effect on temperature and the hypothesis is incorrect. Same conclusion for the cooling period of 1945-1976 when CO2 increased.
“Only one possible conclusion. CO2 has a small effect on temperature and the hypothesis is incorrect.”
That’s the conclusion I reach.
The conclusion I reach is that the “small effecr” is so small as to be unmeasurable.
That’s what observations support. Too many reverse correlation occurrences to “credit” CO2 with ANY effect on temperature.
“So the hypothesis only explains 50 years.”
Again, the hypothesis that arsenic kills does not explain many deaths. But it’s true.
It’s a conditional hypothesis. If CO2 increases, you’ll see warming. If CO2 doesn’t increase, you may well see variability for other reasons. There is no use looking for correlation of T with CO2 if CO2 does not vary. And it won’t vary without cause – conservation of mass.
As for the supposed cooling period, here is the GISS plot. There was a blip around 1940, but otherwise steady rise for a century:
We cannot claim to understand death (climate change) if we only understand death by arsenic.
Why the planet cooled between 1945 and 1976 is not understood, underscoring our poor knowledge about climate change. Why the earth warmed so much between 1910 and 1945 is not understood, underscoring our poor knowledge about climate change.
The issue is not if CO2 causes warming. It does. The issue is to understand why the climate has changed and is changing. And we don’t.
“We cannot claim to understand death (climate change) if we only understand death by arsenic.”
But your logic says that if not many people are dying of arsenic, then arsenic can’t be harmful.
There is a conditional involved. Arsenic is harmful if you eat it. And CO2 causes warming if you pump it into the air, as we are seeing. The rest is a different story.
Nick, even by your standards, that was pathetic.
Unless you are trying to argue that the affect of arsenic changes over time, then your comment has nothing to do with the comment you are replying to.
Like the warming effect of CO2, the effect of As does not change over time. The issue is just the conditional. If you eat As, it’s bad; if not, not. If ppm CO2 in the air rises, it causes warming; if not, not. If you died from something else, that says nothing about As. If it warmed for some other reason, that says nothing about CO2.
None of this affects the basic issue that if you do burn a lot of mined C, which has never happened before, it will cause a lot of warming.
No. It will create a forcing. Whether that forcing results in an increase in temperature, and if so how much, depends on how the planet reacts to it. The evidence from observational studies of what it has done so far is that it will cause a modest and un-alarming amount of warming. Not a lot.
The logical difficulties for the CO2 argument are two.
One, that the older warmings appear to precede rises in CO2, not follow them.
Two, that we have the RWP and MWP, roughly comparable to recent warming, with no increases in CO2.
So the advocate is reduced to making an argument of the following sort: this time its different. There have been similar temperature rises in the past, the MWP and RWP, caused by we know not what. But this one is different, it is not caused by the same thing (whatever that was). No, its caused by CO2 emissions.
To maintain this takes real intellectual contortions.
This is why we get the Hockey Stick, the effort to get rid of the MWP. And why, if you ever mention in an Ars forum that rises in CO2 come after earlier rises in temps, you will immediately be proscribed.
“The logical difficulties for the CO2 argument are two.
One, that the older warmings appear to precede rises in CO2, not follow them.
Two, that we have the RWP and MWP, roughly comparable to recent warming, with no increases in CO2.”
Those are not logical difficulties. Glacial events were not caused by CO2; no-one thinks they were. CO2 followed T as oceans warmed.
RWP and MWP were not comparable to recent warming, but anyway, were caused by something other than CO2.
Past warmings were generally not driven by CO2. That doesn’t mean putting a lot of CO2 in the air won’t cause warming. It hasn’t been done before, so we’re finding out.
Not true Nick, it has happened before in the Mississippian Visean Period, ~340 Ma. Oxygen is probably the determining factor, when it rises, fires start, and they burn and burn until enough is converted to CO2 to extinguish them. Something to consider, remember the Apollo 1 disaster? See here:
The rise of fire: Fossil charcoal in late Devonian marine shales as an indicator of expanding terrestrial ecosystems, fire, and atmospheric change | American Journal of Science (ajsonline.org)
See attached figure from the paper that compares O2 levels to the presence of charcoal.
“Oxygen is probably the determining factor, when it rises, fires start, and they burn and burn until enough is converted to CO2 to extinguish them.”
I don’t see that in your link; it basically just says that fires could not exist before there was enough oxygen in the air to sustain combustion. Vegetation fires could never significantly deplete oxygen. There are 10^15 tons of oxygen in the air, and about 5×10^11 tons of carbon in the land biosphere.
Need evidence that CO2 is the cause of the current very modest warming we have seen in the last 50 years. The null hypothesis must be that its natural and due to the same thing as caused the RWP and MWP. And will have the same prognosis, that is, it will be a cycle of up followed by decline.
I understand there is a worthwhile hypothesis, that this time is different and is being caused by CO2, and there is a whole line of reasoning about feedbacks and water vapor amplification. Where is the hard evidence?
You cannot just assume that because there is a modest initial forcing from CO2 emissions that these are the cause of the current small rise, or that they will lead to large and genuinely alarming rises in the distant future.
It’s all been done before, which is why coal (and oil/gas) exist in currently some of the earth’s coldest regions.
“Past warmings were generally not driven by CO2”.
WTF!
How do you supposedly know?
Don’t you realise most of Russia’s gas comes from Siberia, and oil is going to be from the most northerly artic regions(with western investment), once Russia figures out how to stop killing people in UA.
CO2 levels have always FOLLOWED temperatures sometimes with huge lags.
I know philosophy is not your strong point, but causality is not proved by some half century correlations v 8000-10 000yrs + ridiculous statements reeking of ignorance.
“The evidence from observational studies of what it has done so far is that it will cause a modest and un-alarming amount of warming.”
No, sorry, there is no evidence CO2 is causing any detectable warming in the Earth’s atmosphere.
The warming could just as easily be natural variation. We have evidence natural variation in the recent past has warmed the Earth’s atmosphere to the same degree it has warmed today, and this warming occurred when much less CO2 was in the atmosphere.
No warming of the Earth’s atmosphere can be directly traced to CO2. It’s only in the computer models. And the computer models are worthless.
Nick Stokes: “None of this affects the basic issue that if you do burn a lot of mined C, which has never happened before, it will cause a lot of warming”
WR: My version: “(…), it will cause [a certain quantity of] initial surface warming.”
‘Initial’ means: before surface cooling kicks in. Evaporative-convective surface cooling is not only huge but also very dynamic. Tropical cloud cooling (by reflection) has to be added. How much of that initial surface warming will remain after induced evaporative-convective + tropical cloud cooling?
“Evaporative-convective surface cooling”
It doesn’t cool the globe. It just transfers heat. The latent heat that cools the surface is given back with condensation.
Nick Stokes: “[“Evaporative-convective surface cooling”] It doesn’t cool the globe.”
WR: If evaporative-convective cooling cools the surface, there where we live and measure our [surface] temperatures, what is the remaining problem?
The cooling cycles on a scale of days. The heat doesn’t leave the surface for long.
Nick: “The heat doesn’t leave the surface for long.”
WR: The problem at the surface is the near-perfect greenhouse atmosphere above. Above the clouds, most water vapor (the main greenhouse gas) and clouds (greenhouse factor nr. 2) are lacking and radiation to space is much more efficient than radiation from the surface. The same for the wide and relatively cloudless high-pressure areas where dry air is returning to the surface: they also show a much higher efficiency for spaceward radiation. Heat entering space does not return, and as a result of the whole process, not only the surface but also the Earth (surface + atmosphere) cools.
A simple but very effective system to remove ‘excess’ heat from the surface.
Convection means that the heat is released above almost all of the greenhouse gases, which means that almost all of the heat is lost completely.
However, it does so continuously. It is not an isolated event.
It absorbs heat at the surface, then releases it above 90% of the atmosphere, including more than 90% of the greenhouse gases.
That means that most of the heat that is “given back” is lost immediately to space.
Increased water cycle is a major feedback, and one that is ignored by all of the climate models.
Actually, it does cool the globe. Not only is heat transported high in the atmosphere, but the water vapor content of the upper atmosphere is reduced. The globe is cooled.
They may not believe it, but they sure imply it in AR6!
From AR6, page 179:
What is the/your difference between “mined” CO2 and naturally emitted CO2?
Which past millennia are you referring to? Pre – human? Dinosaur era? Eons of large scale volcanic/seismic activity?
if you are correct in your preconception that CO2 = world on fire, is it human released CO2 only, would you advocate eradicating other large scale “CO2 releasers” being reduced? Which of the latter, if any, would you exclude from your wish list?
“which has never happened before, it will cause a lot of warming”
Can you prove how much? If you can’t prove it, then don’t say it.
“If you can’t prove it, then don’t say it.”
Climate Change Alarmists wouldn’t have anything to say in that case because they can’t prove anything they claim about a connection between the Earth’s weather and CO2.
NB : Your words. “A” dominant influence, not “the” dominant influence.
IPCC AR6 WG-I assessment report, Figure TS.1 (in the “Technical Summary” chapter, on page 44).
“it will cause a lot of warming”
Science by the voices in the head method.
For real scientists, there’s data.
Please Nick, despite all the CO2 emissions the SH is no warmer now than 1970s. Radiative theory does not explain surface temperatures. Alebdo does are far better job.
https://reality348.wordpress.com/2021/05/15/does-carbon-dioxide-cause-the-planet-to-warm-the-cooling-thats-in-process-where-and-why/
There’s a lot more observation based discussion at this site too.
“despite all the CO2 emissions the SH is no warmer now than 1970s”
Just not true. It has warmed consistently, but slower than the NH, because of oceans. Here is the GISS plot:
Nick,
Thanks for showing that the Southern Hemisphere responds much slower than the NH. And those are high resolution instrumental measurements.
Ignore anything on that chart before 1979. The data before that time has been seriously bastardized to make it appear the past was cooler than the present, when, in fact, the past was just as warm as it is today.
In other words: CO2 has had little effect on temperatures since there is much more CO2 in the atmosphere today than there was in the recent past, yet the temperatures today are no warmer than they were then. No big, or even discernable increase in warmth from CO2.
So this source from the link is wrong? Perhaps uncertainty is greater and the science is not settled. Noaa versus giss….
Well, for a start that plot is January only. But also it is NCEP reanalysis, which is not very reliable before about 1990.
You are making an assumption for which you have provided no evidence. Inasmuch as coal beds are laid down horizontally, if the area experiences subsequent uplift, erosion will expose the beds and allow oxidation. If the beds are folded, then erosion will cut through the edges of the formerly horizontal beds. They can then be oxidized. Additionally, they are subject to spontaneous combustion from oxidation of the coal and included pyrite/marcasite, and ignited by lightning strikes.
In the case of crude oil, structural traps can be, and almost certainly have been, decapitated by erosion, not only exposing the pooled oil to oxidation and decomposition by bacteria, which produce CO2, but in the case of pressurized systems like the classic Spindle Top, release the oil rapidly. It’s just that no one was around to observe it.
You further assume that any and all feedback loops have a net positive effect, without demonstrating empirical evidence to support it.
Hi Clyde,
Awesome geologic synopsis on the natural exposures of subsurface carbon sources. The outcropping thick coal beds in Healy Alaska burn routinely every summer. There are subsurface hydrocarbons bubbling up through natural fault zones into the pristine lakes in the Naval Petroleum Reserve Area, NPRA. The poor caribou get stuck in them and die. And we used to cap natural heavy oil seeps off the coast of California, not sure who’s doing that now.
In west central Colorado we have a few coal seams in perpetual combustion. Some, they have tried unsuccessfully to extinguish. Lightening is the combustion source.
Basically, any place where there is a local/regional unconformity created by missing carboniferous-age beds (or older coal-bearing strata) is evidence that the carbon-rich layers have been stripped away by erosion, and oxidized in the process.
If you haven’t read it, you might want to look at
http://wattsupwiththat.com/2015/05/05/anthropogenic-global-warming-and-its-causes/
where I touch on the issue of coal fires, natural and anthropogenic-caused. Of course, Stokes took issue.
And where did all that sh..tload of Mineable C come from pray Mr Stokes….??
duh….
plants which grew like crazy under CO2 levels at least 2-3 x higher than today!
Strangely enough, life on earth seemed to be pretty good in those days keeping the huge numbers of mostly Vegetarian dinosaurs fed, and a sea teeming with all sorts of fish.
Places like Oxfordshire and the Baltic states were vast tropical seas (as you can see from the fossils I pick up).
Earth meanwhile seems to have survived being “burnt to a crisp”, as predicted by the IPCC/Houghton et al in the past pretty well.
That was a highlight of Gore’s science fiction movie An Inconvenient Truth but is not the scientific basis for the premise that all else being equal doubling the concentration of atmospheric CO2 will cause about +1C in global temperature.
It is impossible to measure climate sensitivity empirically because it is impossible to construct a model including all known and unknown natural climate factors that may be augmenting or moderating the effect of the increasing concentration of CO2 over any particular time frame.
“It is impossible to measure climate sensitivity empirically because it is impossible to construct a model including all known and unknown natural climate factors that may be augmenting or moderating the effect of the increasing concentration of CO2 over any particular time frame.”
That’s it. That’s the state of the art today. The truth is we don’t know if CO2 is net warming or net cooling the atmosphere.
Because the answer is ocean changes. The ocean proxies are very warm during the early holocene then keep cooling. One can see it in the Svalbard Island proxies to the Antarctic Proxies. Anything near the ocean was very warm while it took millennia to melt the giant 2 mile high ice cubes on the European and NA land masses so those proxies change from there. It’s the transport of heat from the tropics that changes. There was a large amount of warm waters stratified were salty waters pushed downward warming the oceans which then released and started cycling through cold waters going down to the bottom of the oceans pushing up and pulling warm waters to then poles and the waters cool as we have seen. The overall temperature of the planet most important factor is movement of heat from the equator to the poles through the medium of ocean water. Nothing comes close.
“The Holocene is fortunate to have hundreds of proxy records analyzed by Marcott, 2013, …” This alone invalidates any conclusions drawn by the study authors; Marcott 2013 is scientific fraud.
Rud Istvan in his ebook Blowing Smoke’s ‘A High Stick Foul’ essay showed that Marcott’s 2013 Science paper (based on his Oregon State University thesis) altered and fabricated data to create a hocky stick blade in his temperature reconstruction. Of the 73 identical proxy series used in both his thesis and Science paper, Marcott altered the timelines of 19 to create the Science HS blade that did not exist in his thesis. For just three examples, he moved the timelines of three different proxy series by 1,008, 510 and 32 years, respectively, to fabricate the blade and, additionally, to get rid of the Medieval Warm Period that was in his thesis.
Consciously or not, when people cite Marcott 2013 they are lying to you.
Evaluation of proxy data is not an easy task. However, it is the geologic evidence we have for Paleoclimate temperatures over the past Holocene. I didn’t use any of Marcott’s data in the correlations. I only used the more recent proxy evaluation by Kaufman. They both show the same evidence for a Holocene climatic optimum. I agree the hockey stick blade for the recent uptick by Marcott was probably instigated by peer pressure. Notice Kaufman does not include a present day hockey stick in his global reconstruction.
“I only used the more recent proxy evaluation by Kaufman.”
Where can we see Kaufman’s work?
Where can we see Kaufman’s work?
Kaufman, D., McKay, N., Routson, C. et al. A global database of Holocene paleotemperature records. (2020). https://doi.org/10.1038/s41597-020-0445-3.
OK, thanks for that. I will read it. How confident can we be of such proxy data? I can only wonder if there’s any way to prove that any of it is truly accurate?
Proxy data consisting of biological, chemical and physical processes preserved in the past are an indirect indicator of earth’s behavior. They are not near as accurate as instrumental measurements. They also have different scales of resolution. And then there are several methods used to average multi-proxy data together. A standardized method has not yet been agreed upon. With all the caveats, I don’t think we can ignore proxy data, they need to be used in a more qualitative manner. I will say that most proxy studies tend to show the same general climatic trends during the Holocene, particularly in the Northern Hemisphere.
Renee, your “I agree the hockey stick blade for the recent uptick by Marcott was probably instigated by peer pressure.” is a larger indictment of the paleoclimatology community than you may have intended. I’m not going to re-fight the Hocky Stick Wars here (go to Stephen McIntyre’s ‘Climate Audit’), but much of the paleo work from Mann’s MBH98/99 through PAGES (including Kaufmann’s contributions) are riddled with data and methodological problems; the track record is very poor and the field’s liars have been allowed to skate away from accountability for scientifically dubious publications, most notoriously Marcott 2013.
Renee,
Each time I see “Marcott” I study again the several Climate Audit articles from a simple CA search of his name.
There are several different errors in the Marcott paper. I ignore those about his fabricated hockey stick in favour of data on the handle going back several thousand years. One aspect is childish simpl
(wifi break -continued). … childish simplicity of uncertainty estimates. I have worked with uncertainty in settings like these for 60 years, in analytical chem labs and in geochemical exploration where we measured in rocks such factors as Ca:Mg ratios, CF Marcott. Later, much work with global temperature metrology. You simply cannot use the low Marcott uncertainties because they omit plausible major errors. It follows that you cannot quote correlation coefficients because the picture you get it unnaturally smooth and looks good while meaning little.
The second of several possible criticisms is with the conversion of proxy numbers to historic temperatures. Again, Marcott ignores plausible big variables, makes unmentioned assumptions like uniform ocean mixing lasting thousands of years and creates a calibration equation so pure it deserves biblical fame for eternity. Stephen McIntyre adds other criticisms of this calibration equation that Marcott combines with his optimistic uncertainties to state that we can measure sea temperatures 10,000 years ago to some incredible accuracy like +/- 0.05 deg C (from my memory) when the scientific reality is that you cannot find any real difference between all of the temperatures and so we have a true past of featureless data, a big blob of nothingness in which researchers’ imaginations make peer -review quality from smelly mud.
I agree with Rud Istvan’s mentions of scientific misconduct.
Those who disagree with me might note that different researchers and different methods give surprisingly similar results. To that I say, emphatically, that you are looking at the refined excellence of modern cherry picking. Geoff S
….
p.s. Renee, I do not disagree with the drift of what you are wanting to say. But, for example, can you really rely on the Law Dome measurements (and I praise workers in this hard effort) when the standards of analytical analysis like replicate measurements down hole, replicate drill holes near to and distant from each other, some at different collar altitudes etc etc are only partly done? Data were initially kept from some other researchers who were given the cancel culture post-modern treatment – the science world deserves better standards before the wild ride of hate of fossil fuels is contemplated.
sherri01,
Yes, there are many issues with proxy data and combining them into regional and global means. That is why I also included the ice cores from the Arctic and Antarctic for comparison. They show similar regional trends as Kaufman’s regional proxy means.
No matter how you slice and dice it, the Antarctic proxy data is unique. And this is where CO2 is measured from, this is what modeled temperatures parallel, and this is used as the key dataset over the past 800,000 years.
I redid Marcott’s analysis using the same 73 proxies, keeping the original dates, and doing the averaging after referring each proxy to its own internal anomaly. The result is very good and agrees very well with biological and geological information (from glacier advances). It clearly displays the main abrupt climate events of the Holocene, as glaciers do.
I used an earlier version of this figure in the chapter I wrote for the recently published CLINTEL report criticizing AR6.
However, I think the 0.5ºC difference between the Holocene Climatic Optimum and the LIA found by Kaufman and Marcott is too little. It might be the effect of included marine proxies. A 1ºC difference looks more reasonable to me. Otherwise, we should be now warmer than the HCO, and biology says we are not. Biology adapts very fast, in just a few decades, and trees should be climbing the slopes of high mountains like crazy. Yet, studies find them significantly below HCO treeline altitudes climbing slowly despite very high CO2.
I did emulations too, here, with later here. Got similar results.
Nick your emulations have the same statistical (averaging) problems as Marcott’s and Mann’s.
How is Javier’s different?
Going on 2 days now. Questions that Mr. May can’t answer become beneath his dignity.
Javier,
I was on about uncertainty.
Calculate it pessimistically, including the large errors that are usually ignored and you are left with thin air.
Geoff S
The 0.5 deg difference is too small. I think it is due to the statistical methods used and the global averaging. Both work to remove variability, especially since natural temperature changes occur by latitude, causing the hemispheres to work against one another. Global averaging, combined with varying temporal resolution (some proxies only give us a value every 200-500 years) remove extremes (Abrupt climate events), which often appear and disappear in 200 years.
sherro01, your “I ignore those about his fabricated hockey stick in favour of data on the handle going back several thousand years.” has a weakness: Of the 19 (of 73) proxy series Marcott redated, one of them he redated by over 1,000 years to move a temperature uptick from the Medieval Warm Period (to get rid of it) into his Modern Warming Period hockey stick blade. So Marcott’s hocky stick handle was also fabricated.
It’s all garbage, we really are counting Dancing Angels
Why: We’re presented, here and elsewhere, with temperature proxies.
These being things supposed carved into tablets of stone (ice in Antarctica’s case) are are irrefutable.
One of the supposed best and longest (timewise and geographically) being the Oxygen Isotopes which I presume are being used here.
There are 2 very real problems with Oxygen (3 really as it is also a Green House Gas)
One: The Oxygen isotope ratio is often measured from ancient fossils buried in sediments.
But that is a ‘Life Process’ and oddly enough, ‘life’ does not especially use Temperature as a nutritional input.
We all around here recognise, know and acknowledge this from the Hokey Cokey Stick
i.e. Trees are not thermometers and neither are or were the critters that made fossils.
Two: Especially pertinent to Antarctica and a really simple explanation for the conundrum the story is explaining:
Quote:“Isotopes recovered from ice core are lighter than ocean water due to path fractionation – the process by which heavier isotopes are “rained out” so by the time they precipitate over higher latitudes there is a light isotope bias.
Most of what we know about climate change over the last 2 million years comes from ice core samples from the north and south poles.
From here
So, critters in the warmer parts of the world absorbed ‘A Certain Oxygen isotope’ because the other isotope preferentially evaporated and its all they had left to drink.swim.eat.
So that gives us some sort of ratio. OK
Two (a) But does it tell us how much evaporation there was or how active the critters were?
Are the 2 things related?
IOW: Were the critters on a nutrient-induced ‘high’ or a ‘temperature trip’?
But on its way to the pole, south pole especially where it was preserved, Certain Isotopes in the evaporated water didn’t make it – they preferentially rained out en-route.
As an aside: What did the critters in the water/land make of that ‘isotope enriched rain’? How might that corrupt the record?
Two (b) Does the Oxygen ratio in the preserved ice tell us how rainy it was over the southern oceans or how far it is from the ‘evaporation place’ to Antarctica?
Basically, Oxygen isotope temperature proxies are such as shonky as tree ring proxies with the added haha advantage that you first need to know ‘how long is a piece of string‘
The Holocene Optimum came to an end because ‘somebody’ chopped and burned a rainforest that existed where The Sahara now is.
And deserts are Cold Places. They contain no energy. Deserts are Hell
The rainforest was on ‘borrowed time’ because of its geography on very ancient soils but was thriving immediatly after the glaciation because of all the soil nutrition that had been stirred up by the ice sheets/glaciers during the actual glacial.
The ice sheets worked as ploughs do.
Why the flourishing forest caused temps to be ‘high’ is not because they were = high but because the forest trapped and stored an immense amount of water – in itself and in the soils underneath it. Plus rivers lakes swamps bogs moors mires shallow-aquifers etc etc
The stored water caused the temperature ‘highs’ (daily and annually) to be very modest but also the temperature lows to be equally modest – that is what ramped up the average.
(Because of the 31°C limit that comes out of any simple calculation of what the sun does to deep water – or – any damp, wet or waterlogged place.
Such as a Rainforest.
When the trees were chopped (humans hate trees – they have nothing for us) all that water went, the energy it contained & stored went – to Antarctica. Thanks to a thing called weather.
Exactly as we see in the graphs presented here.
Thank you Peta,
We are thinking alike about assumptions of the ability to overlook the potential for gross errors.
Geoff S
The generally accepted explanation for the Sahara is a 41000 year cycle of the earth’s axis tilt – not hatred of trees. The Sahara will be wet and green again…..in time. Most people love trees.
Most of what we know about climate change over the last 2 million years comes from ice core samples from the north and south poles
Actually, I believe ice cores only go back about 800,000 years ago. And they represent the coldest environment on our planet, Antarctic.
Thank you Renee for a very interesting article with lots of data.
I second that!
Excellent article, Renee!
Methinks the true Climastrology believers wish to return to the storied days of yesteryear and spread the frozen tundra of Lambeau Field as far and wide as possible! They would bankrupt advanced societies to return CO2 to levels near the death threshold for plants, while the piratical elites profit from the looting and plundering of the poor and middle class to provide subsidies for their Unreliable Energy scams and NutsZero diktats!
THERE IS NO CLIMATE CRISIS!! We are in much greater danger of a die-off from LACK of CO2 than anything that the climate hucksters preach to their flock! Like all the other sects within the Marxist religious movement, one must be ignorant, an idiot, or insane to become a true believing “Climate Warrior!”
Averaging the outputs of temperature models (“ensembles”) is nonsense.
“Modeled temperature profiles parallel the global CO2 trend with a strong R^2 of 0.7 confirming CO2 is a major model control knob.”
I would not call a r^2 = 0.7 “strong”.
“… confirming CO2 is a major model control knob.”
Yes, another way of looking at it is that 30% of the variance cannot be explained by the chosen variable.
karlomonte,
In earth science work, I agree with your suggestion that R^2 of 0.7 is weak.
But then, how many researchers have actuall gone through the whole cycle of creating a project, designing it, assembling the instruments, measuring, analysing etc etc. Unless a researcher does this, as in working with the numbers of others, it is very easy for preconceptions and cherry picking to creep in.
One of the big sins with R^2 is leaving out extraneuos variables that, if included, would lead to far lower values.
Geoff S
Model temperatures by construction are correlated with CO2; that’s how they were created. Adjustment factors used by NOAA/NASA are highly correlated with CO2 as well. THis is how they introduce a correlation between CO2 and reported temperatures. The raw measured temperature data is much less correlated to CO2 compared to the reported “adjusted” data.
Milankovitch explains why Antarctic temperatures are low during an interglacial optimum, but rise as Earth moves back into glaciation in the ~3.5 million year old ice age … CO2 does not.
CO2 is rising from the HCO as the biosphere dies back. This explains the underlying rise in CO2 independent of temperature and emissions in the recent past (just do the regression analysis). Once again they have it backwards…
I remember people here had a dig at Peter Heller for suggesting that the ice being near the sublimation temperature of CO2 is a problem. The concentration of CO2 is too low.
But, CO2 does absorb to the surface of ice, and there is lot of surface on snow crystals. It should affect the amount of CO2 that get a trapped as it compresses into ice with air bubbles. I can’t say that there is, but I suspect a temperature dependence on how much atmospheric CO2 is trapped with surface temperature.