By Andy May
I find it amazing that some papers still state:
“air temperatures in the [Arctic or globally] are now at their warmest in the past 6,800–7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene.” (Lecavalier et al., 2017)
While it is remotely possible that current Arctic or global average temperature is higher than any seen in the past 6,800 years, it is very unlikely and can’t be demonstrated with data we have today. It is almost certainly true that the rate of change in global or Arctic temperature observed recently is not unprecedented in the Holocene Epoch. This modern myth has been thoroughly debunked in the literature and seeing it pop up in PNAS and elsewhere is disconcerting. I thought peer-review was supposed to catch such errors.
Warmest in the past 6,800-7,800 years
The first assertion in Lecavalier et al.’s paper is that the Arctic is now warmer than at any time in the past 6,800-7,800 years. The warmest time in the Holocene (12,000 years ago to the present) is generally accepted to be the Holocene Climatic Optimum or the Holocene Thermal Maximum, both names are used. Two of my favorite Northern Hemisphere Holocene temperature proxies suggest that today is only warmer than the past 1,000-2,000 years as shown in figure 1.
In figure 1 the Rosenthal Makassar Strait proxy represents sea surface temperature (SST) in the Northern Pacific and the Vinther Greenland proxy is an air temperature proxy in northern Greenland (more details on Vinther and Rosenthal can be seen here). Kaufman et al. (2009) show us a set of Arctic proxies and show them combined in figure 2, which is from the corrected version of the Kaufman, 2009 supplementary materials.
The same modern discrepancy between the tree rings and the other proxies can be seen in Kaufman et al.’s figure 3A, reproduced as our figure 3 below.
There is general agreement that summer Arctic warming is driven by Earth’s orbital cycles, especially precession and obliquity (see figure 4). This post was inspired by a discussion on a previous post, the critical comment is here.
Figures 2 & 3 show that both recent Greenland area sediment and ice core proxies decline after ~1940, but the tree ring proxies mostly stay high. We will remember that the late Keith Briffa (Briffa et al., 1998b) warned us that tree ring proxies diverged from other proxies in 1998, he speculated that increasing CO2 probably had a lot do with this divergence. The divergence and Michael Mann’s attempt to hide the problem led to the now famous “hide the decline” (McIntyre, 2014) & (McIntyre, 2011) scandal after the 2009 CRU email dump. I have no answer for the divergence or the apparent time shifts between proxies in figures 2 & 3 but warn the reader that proxy temperatures are not temperatures that are comparable to thermometer readings we make today, they are just proxies and dates for the proxy readings are uncertain.
The top illustration in figure 4 shows the elements of the Milankovitch cycles (Haigh, 2011). The seasonal curves in the bottom illustration (Vinós, 2017) show the impact of precession. The seasonal curves are labeled with the hemisphere (N or S) and the first letters of the months. The heavy curves are the summer months of the Northern Hemisphere (red) and the Southern Hemisphere (blue). The changes in insolation are represented by the background color (scale to the right in W/m2). The black curve shows the δ18O isotope changes from the NGRIP Greenland ice core analysis, a temperature proxy (Alley, 2000). The δ18O temperature proxy has no scale, but higher temperatures are up and lower temperatures down. The vertical scale is latitude, and the horizontal scale is time from 40,000 years ago to the present and zero on the background color scale is the insolation by latitude today.
The changes in the background color (insolation) in the bottom illustration in figure 4 are mostly due to changes in Earth’s orbital obliquity and are approximately symmetrical with regard to the hemispheres. The changes due to obliquity determine how much insolation reaches the poles versus the tropics. Precession on the other hand affects the seasonal distribution of solar energy, so as you can see, the end of the last glacial period at the beginning of the Holocene 11,700 years ago was when obliquity and precession were maximal in the Northern Hemisphere. Maximal precession means the difference in the Northern Hemisphere summer and winter was maximal, the total insolation by latitude remains about the same. Maximal obliquity means both poles receive the maximum insolation they will get, at the expense of the tropics.
Other interesting things to note in the lower part of figure 4 are that insolation barely changes throughout the Holocene in the tropics but changes a lot at the poles. The N-JJA (precession) curve looks a lot like the Makassar Strait and Greenland proxies in figure 1, notice the Holocene Climatic Optimum and Neoglacial labels in both figures 4 and 1.
Figure 5 shows the full Vinther and Rosenthal curves and relates them to historical events. Click on the figure or here to see at full resolution.
There are a large number of historical references in the timeline shown in Figure 5 and we will not explain all of them here, they are well documented in earlier posts here and here. We will just make the point that significant local climate changes are historical events that are often described in detail by the historians of the time and dated precisely. These historical descriptions can be more valuable than biological or ice core proxies.
As figure 4 shows, the Arctic received the maximum insolation at the beginning of the Holocene 9,700BC (Walker et al., 2009). This was also the time of the fastest change in Arctic temperature during the Holocene. Around 9,700BC Severinghaus et al. documented a 5-10°C warming event that took only a few decades, dwarfing the warming rate we observe today. The warming event is identified in the middle plot in figure 5. This warming event is so significant it is part of the official geological basis for the beginning of the Holocene Epoch (Walker et al., 2009).
The top plot in figure 5 shows the temperature of the 500-meter water in the Makassar Strait, which is representative of the North Pacific SST (Rosenthal et al., 2013). The present-day temperature in the Makassar Strait from the University of Hamburg (Gouretski, 2019) ocean temperature database is shown on this plot as a red box, it is well below the temperatures seen in the Medieval Warm Period (MWP) and the Roman Warm Period (RWP). In the middle plot of figure 5, the Vinther reconstruction (Vinther et al., 2009) is the orange line. The earlier blue line is the Alley reconstruction (Alley, 2000) spliced to it. The HadCRUT5 Greenland temperature average from 2000-2020 is plotted as a red box for comparison to the proxy temperature. The modern temperature in Greenland is roughly the same as the MWP temperature.
Discussion
There is considerable evidence that modern Arctic and Northern Hemisphere temperatures are well below the temperatures of 6,800-7,800 years ago. There is also a lot of evidence that the rate of temperature increase in 9,700BC was much faster than the increase we observe today. Comparing the rate of warming today when we have daily temperatures from all over the world to pre-industrial proxies is problematic. The high-quality Rosenthal and Vinther proxies have a resolution of about 20-years over the past 2000 years, so the modern averages that we compare them to in figure 5 cover 11 years (U of Hamburg) and 21 years (Greenland). It is much easier to reduce modern resolution for comparisons to the past than to try and increase proxy resolution. It is foolish to try and reconstruct global or hemispheric temperature records with proxies; they are very coarse and the averaging process used to make the reconstructions destroys the critical detail needed to determine a rate of warming.
Besides the rapid warming seen in these proxies around 9,700BC, there was also rapid warming around 6200BC, 40BC, and 800AD. Any of these periods could have warmed faster than today if they could be compared with the same coverage and accuracy.
Works Cited
Alley, R. B. (2000). The Younger Dryas cold interval as viewed from Central Greenland. Quaternary Science Reviews, 19, 213-226. Retrieved from http://klimarealistene.com/web-content/Bibliografi/Alley2000%20The%20Younger%20Dryas%20cold%20interval%20as%20viewed%20from%20central%20Greenland%20QSR.pdf
Briffa, K., Schweingruber, F., Jones, P., Osborn, T., & Vaganov, E. (1998b). Reduced Sensitivity of recent tree-growth to temperature at high latitudes. Nature, 678-682. Retrieved from https://www.nature.com/articles/35596
Gouretski, V. (2019). A New Global Ocean Hydrographic Climatology. Atmospheric and Oceanic Science Letters, 12(3), 226-229. Retrieved from https://www.tandfonline.com/doi/full/10.1080/16742834.2019.1588066
Haigh, J. (2011). Solar Influences on Climate. Imperial College, London. Retrieved from https://www.imperial.ac.uk/media/imperial-college/grantham-institute/public/publications/briefing-papers/Solar-Influences-on-Climate—Grantham-BP-5.pdf
Kaufman, D. S., Schneider, D. P., McKay, N. P., Ammann, C. M., Bradley, R. S., Briffa, K. R., . . . Vinther, B. M. (2009). Recent Warming Reverses Long-Term Arctic Cooling. Science, 325(5945). https://doi.org/10.1126/science.1173983
Lecavalier, B., Fisher, D., G.A. Milne, B., Vinther, L., Tarasov, P., Huybrechts, D., . . . Dyke, A. (2017). High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution. Proc. Natl. Acad. Sci. , 114(23), 5952-5957. https://doi.org/10.1073/pnas.1616287114
McIntyre, S. (2011, Dec. 1). Hide-the-Decline Plus. Retrieved from Climate Audit: https://climateaudit.org/2011/12/01/hide-the-decline-plus/
McIntyre, S. (2014, September 6). The Original Hide-the-Decline. Retrieved from Climate Audit: https://climateaudit.org/2014/09/06/the-original-hide-the-decline/
Rosenthal, Y., Linsley, B., & Oppo, D. (2013, November 1). Pacific Ocean Heat Content During the Past 10,000 years. Science. Retrieved from http://science.sciencemag.org/content/342/6158/617
Vinós, J. (2017, April 30). Nature Unbound III: Holocene climate variability (Part A). Retrieved from Climate Etc.: https://judithcurry.com/2017/04/30/nature-unbound-iii-holocene-climate-variability-part-a/
Vinther, B., Buchardt, S., Clausen, H., Dahl-Jensen, Johnsen, Fisher, . . . Svensson. (2009, September). Holocene thinning of the Greenland ice sheet. Nature, 461. Retrieved from https://www.nature.com/articles/nature08355
Walker, M., Johnsen, S., Rasmussen, U. O., Popp, T., Steffensen, J.-P., Gibbard, P., . . . Newnham, R. (2009). Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core,and selected auxiliary records. Journal Of Quaternary Science, 24, 3-17. https://doi.org/10.1002/jqs.1227
His Holiness, Michael Mann, is looking more and more like a fantasist.
But a rich fantasist who made himself poor,
“Michael Mann is facing significant legal obligations stemming from a defamation case. He initially won a $1 million verdict against two bloggers. However, this amount was later reduced to $5,000, and he has since been ordered to pay over $530,000 in legal fees to his opponents, as well as additional sanctions.”
Makes you believe in Karma !!
He won’t put his own hand in his own pocket.
The AGW acolytes will be squeezed for more $$$$$s to pick up Da Man’s bills.
(just like all religious orders do – a tithe by any other name)
Has Mann paid for the judgement from the Tim Ball case? Somehow, I think not.
Nice summary.
I would caution that what is being shown are anomalies which is a rate of change, not absolute temperatures. Deriving an absolute temperature at which the anomaly took place is terribly uncertain within whatever optimum range it might have taken place.
One might look at tree rings and say “this year is 2° warmer than last year”, but establishing at what absolute temperature it actually took place at is loaded with uncertainty.
Hi Jim,
I assume you are referring to figure 2, from Kaufman et al. Figure 1 has actual estimated Greenland temperatures compared to Rosenthal anomalies. In figure 2, all the plots are anomalies from the mean for the same period and all are in deg. C. You should be able to compare them directly with no problem.
This is also true of figure 3, although here they are not in deg. C but in dimensionless units designed to be compared.
In fig. 5, the two main plots (Rosenthal and Vinther) are in actual degrees C. The plot of Christiansen and Ljunqvist’s reconstruction is an anomaly from the 1880 to 1960 average.
Lookee here folks –
a climate scientist prepared & willing to explain his presentations.
What a breath of fresh air!
Thank you Andy for all your diligence.
“a climate scientist”
Who? Where?
Here:
https://michaelmann.net/
But no degree in climatology, let alone paleoclimatology. Titles are for prestige, and are rarely an indication of knowledge of the holder of the title.
I found ten periods with faster warming rates than today in just the last 3,000 years from the Vostok temperature reconstruction. Proxies from Greenland support that it was global. The fastest was 2.6C in 83 years.
Unprecedented warming liars are fraudulent cherry pickers.
“I found ten periods with faster warming rates than today in just the last 3,000 years from the Vostok temperature reconstruction”
And I’m not surprised that you did!
Your faster warmings (even if correct) are not global ones, which I believe is what climate scientists are referencing when they say modern warming is the fastest.
IOW: it is you that is “cherry picking”.
As the Arctic during the lead up and onset of the HCO is bound to have had the greatest warming rates globally, being a rebound from an IA as high northern latitudes experienced a pronounced increase in TSI during the summer months.
65 deg N is the most important latitude with respect to global ice sheets during the IA (any) as it encompasses the greatet global land-mass and therefore the greatest ice extent.
AT it’s height TSI at 65 deg N on the solstice was ~ 50w/m2 higher than present.
If such historic rapid temps rises happened and can be detected anywhere around this planet, the current ones aren’t “unprecedented”.
So why do you make a leap of religious faith that these must have been “global” and “unprecedented”?
(whatever “global” means, as in – did it happen in Antarctica and the Congo at the same time?)
Mr AB – You are conveniently avoiding two big issues. First, there is no such thing as a “global” rate of warming, nor such thing as a “global” temperature
Second, what caused the extraordinary warming that concluded the last major Ice Age and led to the Holocene?
I think it is clear that the precession and obliquity maximums coinciding ~11.7kyr BP as shown in figure 4 caused the end of the last glacial maximum. Remember, we are still in an ice age that began about 2.6 Mya (beginning of the Quaternary). Both the current Holocene warm period and the last glacial maximum are parts of a much longer “Ice Age.”
“Your faster warmings (even if correct) are not global ones”
Ice core reconstructions from Greenland that coincide support that they are. Ignoring that data is the cherry picking going on by climate fraudsters.
So you are saying that the sudden spurious warmings in Greenland ice cores re representative of the whole globe?
How on earth can you come to that conclusion, other than the obvious one … that it is what you would like?
“Ignoring that data is the cherry picking going on by climate fraudsters.”
No one’s “ignoring” that data – what they are doing is using the fact that a proxy taken from ~ 8000ft up on the Greenland plateau is in no way indicative of the entire globe.
An extreme environment subject to air-masses coming from the Atlantic, itself subject to currents that most likely had temperature changes due process such as wind shifts (+ve NAO) or from arctic Canada and the high Arctic itself (-ve AO and -ve NAO). In short the variability (meteorology) involved over a period of millenia.
Your view is what you get when you only have a single variable in mind (that all the data is fraudulent – except the ones you like), added to the nonsense idea that a (6,000 to 10,000ft ) high arctic ice sheet is in any way indicative of the whole climate system. (NB Greenland is just ~ 0.4% of the erth’s surface)
It’s obviously escaped your attention that the climate system is a tad more involved then that.
Again you are the cherry-picker in choosing the data that you like even if it makes no scientific sense, nor indeed even common-sense.
Was the warming/cooling global or isolated the polar regions? That is a legitimate question.
The polar proxies do tend to show much larger temperature swings that the equatorial proxies (including the proxies 40n-40s ish). The polar proxies also tend to be much higher resolution than the proxies as they move closer to the equator, ie the resolution drops. Thus the question becomes how to weight the proxies in the attempts to determine global temps.
One of the issues in the paleo science world is the underweighting of the higher resolution proxies, See page2k and MBH 1998 weighting of the law dome and dome C proxies in their reconstructions
“Was the warming/cooling global or isolated the polar regions? That is a legitimate question.”
It is and it has been answered in the data.
Not least becasue the total TSI impinging Earth did not change significantly, it was just redstributed via obliquity (though with an obvious increase due melted sea-ice later in the Holocene).
This is Mr May’s graph of the Holocene….
“Figure 1. The regional temperature reconstructions shown are in 30° latitude slices, that is the Arctic (green line) is from 90°N to 60°N, the Northern Hemisphere (heavy black line) is from 60°N to 30°N, the tropics are from 30°N to 30°S, the Southern Hemisphere is from 30°S to 60°S and the Antarctic from 60°S to 90°S. The Holocene Climatic Optimum warm period, the Mid-Holocene Transition (MHT), and the Neoglacial Period are identified. Sources: (May, 2018, Chapter 4) and here.”
In my view it shows that as the TSI increased over the Arctic it reduced over the Antarctic, so we see temps rising in the arctic and almost a mirror image in the AA with falling temps. Then as the ice/albedo feedback took over the opposite occured before a stabilisation and the high latitudes cooled as the solar forcing waned and moved south again. Hence the Holocene cooling from the optimum.
In short the hemispheric temp swings cancelled out.
Anthony
Based on what has happened over the satellite era, you are correct. As the Antarctica cools the NH area above 55 degrees warms. The two work in tandem.
“So you are saying that the sudden spurious warmings in Greenland ice cores re representative of the whole globe?”
Do you have reading comprehension difficulties? The Greenland ice cores that match the most pristine Antarctic temperature reconstruction support that they were global events.
The point is we have data that contradicts the fastest ever warming lie. That definitive declaration is not supported by any definitive data.
“Again you are the cherry-picker in choosing the data that you like”
No, I’m pointing out the data the cherry pickers are ignoring. Your straw man fabrications of what I think are without substance. I’m fully aware of the complexity of the climate system. CO2=bad is as deep as alarmists are capable of understanding.
Are you claiming that it is just coincidence that the Arctic was cold while the rest of the globe was warm?
Is this graph a prediction of insolation 100,000+ years into the future?
Didn’t most of the ice in Glacier Bay melt before 1950 when CO2 was still at a ‘safe’ level ?
“Didn’t most of the ice in Glacier Bay melt before 1950 when CO2 was still at a ‘safe’ level ?
Many temperature records are still from the 30’s & 40’s. CO2 probably has a negligible impact on global temperatures compared to natural variability.
“The first assertion in Lecavalier et al.’s paper is that the Arctic is now warmer than at any time in the past 6,800-7,800 years. The warmest time in the Holocene (12,000 years ago to the present) is generally accepted to be the Holocene Climatic Optimum or the Holocene Thermal Maximum, both names are used. Two of my favorite Northern Hemisphere Holocene temperature proxies suggest that today is only warmer than the past 1,000-2,000 years as shown in figure 1.”
Lecavalier’s reconstruction also explicitly shows that the Holocene Thermal Maximum remains warmer than present (defined as 2009)
“Figures 2 & 3 show that both recent Greenland area sediment and ice core proxies decline after ~1940, but the tree ring proxies mostly stay high. “
I refer to my comment from February 3, 2026 1:11 PM, where I pointed out that the depiction shown by your sediment + ice core + no tree ring composite from the Kaufmann et al. database is inconsistent with the observed temperature record.
The 1990s temperatures in the Arctic rival those of the 1930s and come close to those of the 1940s. The 1970s and 1980s were also warmer than preindustrial levels, which doesn’t align with what your panels show.
Then, you yourself (on February 3, 2026 2:15 PM) seemed to agree with my comment. Please feel free to correct me if I’m mistaken.
“There is also a lot of evidence that the rate of temperature increase in 9,700BC was much faster than the increase we observe today.”
Once again, using this event for present comparisons is like comparing apples and oranges as it marks the onset of deglaciation. It’s not particularly relevant to the boundary conditions of the Holocene.
“The earlier blue line is the Alley reconstruction (Alley, 2000) spliced to it. The HadCRUT5 Greenland temperature average from 2000-2020 is plotted as a red box for comparison to the proxy temperature. The modern temperature in Greenland is roughly the same as the MWP temperature.”
I also previously pointed out that Greenland doesn’t track the pan-Arctic temperature evolution very well. The pan-Arctic surface temperature anomaly for 2000 was -0.42°C, and for 2024 it was 1.2°C, a difference of 1.62°C. Greenland, however, hasn’t seen much warming since 2000.
Source: https://arctic.noaa.gov/arctic-indicators/
This difference is most likely due to North Atlantic and AMOC influence and this behavior is not unique to the modern period. During the Little Ice Age, Greenland, Iceland, and Europe experienced especially severe cooling, consistent with those factors.
The key point is that Greenland is not a reliable stand in for the High Arctic as a whole.
Lecavalier’s estimate is compelling precisely because it comes from the High Arctic, where temperature evolution is more directly influenced by radiative forcing and sea ice feedbacks and less filtered through North Atlantic circulation variability.
The hockey stick lives.
Whew! Long comment, well here goes:
True, and that is my point. We need to realize that proxies are not accurate, they are poorly dated, and they are not consistent with one another, even at the same location. This is one of the flaws in the hockey stick and in all reconstructions. It is also why I stick to assessing proxies one at a time and do not (any longer) combine them into a “reconstruction.” Reconstructions are all flawed.
FYI: I discuss all of Marcott’s proxies in my global reconstruction series, see here:
https://andymaypetrophysicist.com/2017/06/09/a-holocene-temperature-reconstruction-part-4-the-global-reconstruction/
Where in Lecavalier does he qualify his statement that modern warming is unprecedented like you have? If he or you, for that matter, admit that orbital forces are stronger than man-made greenhouse gases, by a considerable margin, you would have more support from me. AR6 seems very confused, in some parts they say modern temperatures are unprecedented in 2000 years (p. 41, still not true), in other places they say modern temperatures are unprecedented in 125,000 years (page 61 & 74, completely false and by a wide margin!). Bottom line, our temperatures today are still cooler than normal for the planet.
I agree that Greenland doesn’t track pan-Arctic temperature very well where we have instrumental data, but that is a problem for people making global and hemispheric reconstructions, not for me. These days I only look at individual proxies as you can see in figure 1.
I disagree with this statement, Lecavalier’s estimate is an outlier at best, and fairly useless since he is combining proxies he should not be combining due to elevation history differences that he has not adequately corrected for. His model is likely flawed (see Martin, 2024) and in any case is very likely inaccurate in the corrections made for elevation. I’m not impressed by Lecavalier’s study or his conclusions. Nice try, but not believable.
“True, and that is my point. We need to realize that proxies are not accurate, they are poorly dated, and they are not consistent with one another, even at the same location. This is one of the flaws in the hockey stick and in all reconstructions. It is also why I stick to assessing proxies one at a time and do not (any longer) combine them into a “reconstruction.” Reconstructions are all flawed.”
That doesn’t mean that all proxies are therefore equally unreliable or that consistency with observations should be ignored. A basic precondition for confidence is whether a proxy is 1) is physically interpretable 2) internally consistent, and 3) agrees with the instrumental record over the overlap period.
Some proxies clearly fail that test. Others pass it. When a proxy does reproduce the observed surface temperature evolution where overlap exists, that increases (and not decreases) confidence in its signal.
Lecavalier’s Agassiz record meets that precondition. The Kaufman composite you show does not.
“Where in Lecavalier does he qualify his statement that modern warming is unprecedented like you have? If he or you, for that matter, admit that orbital forces are stronger than man-made greenhouse gases, by a considerable margin, you would have more support from me. AR6 seems very confused, in some parts they say modern temperatures are unprecedented in 2000 years (p. 41, still not true), in other places they say modern temperatures are unprecedented in 125,000 years (page 61 & 74, completely false and by a wide margin!). Bottom line, our temperatures today are still cooler than normal for the planet.”
He does so explicitly in the 1st paragraph of the Significance section:
“ Here, we report on an Arctic climate record from the Agassiz ice cap. Our results show that early Holocene air temperatures exceed present values by a few degrees Celsius, and that industrial era rates of temperature change are unprecedented over the Holocene period (∼12,000 y).”
Orbital forcing dominates glacial interglacial timescales, but that is not the relevant comparison here. Over the last several millenia, orbital forcing trends are weak and gradual, whereas the modern warming rate is rapid and scary.
“These days I only look at individual proxies as you can see in figure 1.”
And we now know that the hockey stick is directly observed in individual proxy records. This is significant because it directly contradicts the skeptics’ repeated claim that the hockey stick arises only from statistical manipulation, an overreliance on tree rings, or the splicing of instrumental data.
“I disagree with this statement, Lecavalier’s estimate is an outlier at best, and fairly useless since he is combining proxies he should not be combining due to elevation history differences that he has not adequately corrected for. His model is likely flawed (see Martin, 2024) and in any case is very likely inaccurate in the corrections made for elevation. I’m not impressed by Lecavalier’s study or his conclusions. Nice try, but not believable.”
Lecavalier combines Agassiz cores drilled at the same ice cap to extend the record forward. This is not an apples to oranges merge of unrelated archives. It is apples to apples.
And their elevation corrections primarily affect early Holocene temperatures, not the modern blade. If you reject Lecavalier’s elevation model instead adopt Vinther style corrections, the implication is that modern temperatures are easily the warmest of the entire interglacial, which is an even stronger conclusion.
He doesn’t say anything about 6,800-7,800 years ago, well in the Holocene Climatic Optimum. You are confusing two things here.
Orbital forcing is only part of the story. The last few millennia have had a number of solar grand minima and solar maxima. We are just coming out a grand solar maximum. See here for a list of Usoskin’s SGMs:
https://andymaypetrophysicist.com/2024/12/02/climate-change-over-the-past-4000-years/
It is observed in very few proxies. The other good proxies were excluded by Mann’s highly modified PC model. This is well documented in multiple papers and reports. Andrew Montford’s book The Hockey Stick Illusion and my book Politics and Climate Change: A History exhaustively go through all the evidence. Too much for here.
As for Lecavalier, I will stick with what I’ve already said.
O18 from GRIP does not show any peak…
Treen rings do not show any recent increase in O18
“He doesn’t say anything about 6,800-7,800 years ago, well in the Holocene Climatic Optimum. You are confusing two things here.”
Not confusing them.
Lecavalier explicitly separates absolute Holocene temperature levels from rates of change. He does not claim that modern temperatures exceed the Holocene Climate Optimum. In fact, he states the opposite (from the abstract):
“Our results show that early Holocene air temperatures exceed present values by a few degrees Celsius…”
What is unprecedented is the modern blade.
“Orbital forcing is only part of the story. The last few millennia have had a number of solar grand minima and solar maxima. We are just coming out a grand solar maximum. See here for a list of Usoskin’s SGMs:”
Agreed that solar variability is important. But it can’t be responsible for contemporary surface warming:
“It is observed in very few proxies. The other good proxies were excluded by Mann’s highly modified PC model. This is well documented in multiple papers and reports. Andrew Montford’s book The Hockey Stick Illusion and my book Politics and Climate Change: A History exhaustively go through all the evidence. Too much for here.”
Disagreements with Mann’s early reconstructions, Montford’s critique, or later methodological debates do not invalidate the existence of hockey stick behavior in single proxy records developed decades later using entirely different methods. Those are separate issues.
You are using FAKE surface temperatures, totally corrupted by urban warming, bad sites , expanding airports and agenda data mal-manipulations.
Show us where the surface temperature was measured before 1940..
… and were the oceans were measured before 2005.
The red line is TOTALLY BOGUS. !
As shown elsewhere, the bogus blade on your initial graph does not exist in other Greenland O18 proxies…
As shown elsewhere, the bogus blade on your initial graph does not exist in other Greenland O18 proxies…”
And as said before, Greenland cannot be considered a reliable stand in for the High Arctic as a whole. A point Andy May agrees to as well.
Yet you are relying on bogus Mannian contrived data from Greenland…
… so funny !!
Wrong. Figure 1, panel A shows the site is located north of 80° N. This is High Arctic Canada, not Greenland.
What is confusing about “6,800-7,800”? You keep saying HCO, we are not talking about the HCO.
In your February 5, 2026 12:20 PM comment, you asked:
“Where in Lecavalier does he qualify his statement that modern warming is unprecedented like you have?”
I answered that directly by quoting the first paragraph of the Significance section.
You then replied with:
“He doesn’t say anything about 6,800-7,800 years ago, well in the Holocene Climatic Optimum. You are confusing two things here.”
So, at that point, you introduced the 6.8–7.8 ka interval, not me.
I responded by pointing out that Lecavalier’s reconstruction shows early Holocene warmth exceeding present day temperatures, including that interval, and that this is fully consistent with his statement, because his claim of “unprecedented” refers to the modern blade, not absolute temperature levels.
That directly addresses your original question, or so I thought.
I didn’t introduce it, Lecavalier introduces it, below is the quote from the top of the post. The whole point of the post was that we are not “at the warmest in the past 6,800-7,800 y” as Lecavalier states. All the evidence says it was warmer than today before ~2,000 years ago, at least both in the Greenland Arctic, in Europe, and over the North Pacific.
“air temperatures in the [Arctic or globally] are now at their warmest in the past 6,800–7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene.” (Lecavalier et al., 2017)
The debate has nothing to do with the idea that the HCO (8,000 to 4200BC) was warmer than today, I think nearly everyone agrees it was, that is not an issue.
As Solomina, et al. note, “during the first millennium CE glaciers were smaller than between the advances in 13th to early 20th centuries CE.” Glaciers are very sensitive climate indicators since they take so long to build and so long to melt. Glaciers are still very advanced relative to the first millennium.
https://www.sciencedirect.com/science/article/abs/pii/S0277379114004788
Take a look at the areas covered by Solomina in her figure 1.
“ All the evidence says it was warmer than today before ~2,000 years ago, at least both in the Greenland Arctic, in Europe, and over the North Pacific.”
Those regions are not independent of large scale circulation effects, particularly Greenland and Europe (AMOC, AMO, etc.). I’m less certain which mechanisms dominate the North Pacific, but in any case, extrapolating from these three regions to critique a High Arctic ice cap reconstruction certainly requires caution.
The High Arctic is one of the most sensitive regions to global mean warming, a fact directly observed in the instrumental record. High Arctic temperature records exhibit the same large scale temporal structure seen in the global mean (early 20th century warming, mid century cooling, and late century warming) but with substantially larger amplitude.
“As Solomina, et al. note, “during the first millennium CE glaciers were smaller than between the advances in 13th to early 20th centuries CE.” Glaciers are very sensitive climate indicators since they take so long to build and so long to melt. Glaciers are still very advanced relative to the first millennium.”
Solomina et al. also explicitly say in their abstract:
“The rate and the global character of glacier retreat in the 20th through early 21st centuries appears unusual in the context of Holocene glaciation, though the retreating glaciers in most parts of the Northern Hemisphere are still larger today than they were in the early and/or mid-Holocene. The current retreat, however, is occurring during an interval of orbital forcing that is favorable for glacier growth and is therefore caused by a combination of factors other than orbital forcing, primarily strong anthropogenic effects. Glacier retreat will continue into future decades due to the delayed response of glaciers to climate change.”
What you write in your comment is true, but irrelevant to the point of my comment. I repeat:
Thus, Lecavalier et al. 2017’s “6,800 to 7,800” BS is wrong.
That logic only works if those regions are valid stand-ins for the High Arctic conditions Lecavalier is addressing. You are making an apples-to-oranges comparison.
As I have said many times, and in this post, combining proxies into a reconstruction is useless, all reconstructions are wrong, even mine.
Deal with proxies one at a time.
February 2, 2026 4:06 PM
“…the data themselves remain ice proxy measurements throughout.”
GISS (red line) is nothing but a proxy of sparce and non-existent sites, urban warming, airport sites, horrendously bad unfit-for-purpose surface sites, totally fabricated sea temperatures, and massive data manipulation.
It has absolutely nothing to do with real temperatures.
Recent remote sensing satellites demonstrate that surface temperatures can and do change abruptly laterally, and carry the imprint of anthropogenic land use changes. That level of detail was unavailable prior to satellites.
“Agreed that solar variability is important. But it can’t be responsible for contemporary surface warming:”
The grand solar maximum was the highest output in thousands of years according to several papers. You fell for propaganda that said the sun can’t be responsible because TSI was declining. The average lows in TSI were above previous highs for 60 + years. More energy was coming in than normal for the entire period amplified by the reduction in clouds during the modern warm period. The increase in solar radiation reaching the surface in the 21st century due to that far exceeds the human forcing during the period.
I might add that TSI is not the only factor in solar variability that affects climate. See Joanna Haigh’s excellent report on the sun and climate:
https://www.naturalsciencesection.org/wp-content/uploads/2019/08/Solar-influences-on-Climate-Haigh-1.pdf
Cloud fraction has way more impact than TSI on how much solar radiation reaches the surface. The reduction in clouds during the modern warm period a prime example!
Will read the report when I have time. Thanks!
True
She makes a lot of false conclusions- “the warming in the latter part of the 20th century is almost entirely due to the increasing concentrations of greenhouse gases from human activity. ”
The well documented reduction in clouds during the modern warm invalidates that conclusion. 1/3 of modern warming is the most that could be attributed to human emissions based on the W/m^2 increase in solar radiation reaching the surface. 3 peer reviewed papers concluded that all of modern warming can be explained by the cloud reduction.
I agree with you, but if we ignore all her work just because some of her conclusions are wrong, we will miss a lot. I can’t tell you how many otherwise good scientists have made stupid conclusions about man-made climate change. You need to skip over the BS and concentrate on the good stuff and especially the good data.
Yes, there was a lot of good information and analysis in the paper. The attributions that modern warming is more from human emissions than the solar forcing is wrong. Hard for me to respect invalid conclusions.
Deception often works by saying a bunch of things that are true so people let their guard down then they slip a lie in that sticks because of that.
Same data. Longer integration to account for, among other things, for ocean integration.
Robert, can you explain the physical basis for using an 88 year smoothing window on the solar data, and for applying a 20 year temporal offset? What mechanisms justify those choices?
Infinity times infinity.
It’s not just a smoothing window. Besides modeling ocean integration, it also decodes solar activity. The correct length is 98-99 years — an integer multiple of 11 — when properly applied to unmolested sunspot data. The length is tightly constrained by the orbits of the Jovian planets.
The offset using a 99-year moving average was empirically found to be ~13 years. The 20-year offset should be closer to 24 years with the shorter filter, but the TSI data is modeled (Satire-T) whereas the sunspot data is observed.
The Jovian planets are also linked to the 3560-year repetition in climate. Here, three different ice-core reconstructions are shifted by 3560 years and compared. This doesn’t work very well with reconstructions that are combinations of data from multiple r locations (e.g. Vinther).
Maybe not, but the fact that adding CO2 to air does not make thermometers hotter does.
Hockey sticks are for hockey players.
You can find a proxy that matches any scenario you can dream up, see figure 2 in the post for an example. For many more problematic proxies see this series on Marcott’s proxies:
https://andymaypetrophysicist.com/2017/06/09/a-holocene-temperature-reconstruction-part-4-the-global-reconstruction/
There are always a few that any fool can latch onto to “prove” anything.
This is far from an idealized or selective scenario. The reconstruction is internally consistent, and its modern extension is independently corroborated by the instrumental surface temperature record from the High Arctic. And beyond this, it exhibits the expected Holocene evolution: post deglacial warming, an early Holocene thermal maximum, and subsequent orbitally driven cooling.
The fact is that the Earth is hotter than its environment, and hence must cool. No “heating and cooling” cycles. That’s just deranged “climate” pseudoscience.
Your appeals to the authority of ignorant and gullible pseudoscientists don’t turn fiction into fact.
Nature can’t be fooled. The journal “nature” can, of course. Even by pathetic frauds, as “Mike’s nature trick” demonstrates.
GRIP O18 derivations do not show any spike.
image….. Greenland O18 from 6 sites.
Notice how Mr. Nice turned a very noisy signal into a wiggly line.
Here’s what it should look like:
https://www.researchgate.net/figure/Greenland-temperature-and-stacked-d-18-O-ice-records-over-the-past-4000-yr-Error-bands_fig1_307841256
Perhaps one day he’ll cite Kobashi et al. (2011)?
The hockey stick is FAKE. Must be from a Mannian disciple.
018 derivation from 6 sites shows no such thing
Op. Cit.
Looks pretty reasonable to me and vastly less noisy than Mann’s hockey stick plot.
One reconstructs of eight data points, Graeme, the other a whole hemisphere.
I hope you can distinguish the size of both, even cats do.
And O18 for GRIP Greenland since 1400 shows no such spike
The reason Mr. Nice is galloping is quite simple:
https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change/
To deny the obvious takes dedication.
The spike at the end is from ~2000 or so, whereas the resolution of the proxies is > 20 years. Thus, to be a correct comparison scientifically, it should be shown as a single point average. That period ~1998 to today, once properly averaged is about the same temperature as the peaks around 400AD, 750AD, and 800AD, within the margin of error of the Greenland proxies, which is ~+-0.3 deg. C for a 20-year point. Thus, the graph really says the opposite of what you want it to say.
The rest of your comment is speculation about the future and has no substance.
To have a single point you’d have a gap, Andy, which isn’t in line with the rest of the graph.
Not a trader, are you?
A gap is better, it shows you are comparing apples and oranges.
The graph shows which are apples, Andy, and which are orangutans. It’s explained right above it, and under the title.
But it’s nice that you realize there are uncertainties out of a sudden, which means your “remotely possible” in your essay amounts to a forceless jab.
Tree rings from Greenland so no such thing.
In one subthread, Mr. Nice suggests that contemporary tree rings are meaningless.In another, Mr. Nice uses them.
Here’s something more serious. I’ll let readers find back this source. It’s from Andy’s. He kinda forgot to post that graph.
?? I have no idea what you are getting at, you will need to explain what your point is.
Which part of “In one subthread, Mr. Nice suggests that contemporary tree rings are meaningless.In another, Mr. Nice uses them” you do not get, Andy?
Perhaps you should stick to ignoring me.
Good idea, but contemporary tree rings are meaningless as shown by Briffa, 1998 – and fully demonstrated by Mann with his useless hockey stick.
Yet Mr. Nice just used tree rings from Greenland, Andy, and of course “Briffa, 1998” hasn’t shown what you claim it showed.
Besides, you should know by now that contrarians’ favorite Mike has more than one hockey stick.
Willard,
There are dozens and dozens of reconstructions of the past 2000 to 12000 years, and they are almost infinite in their variety. Showing, in my opinion, they are useless. Go through the individual proxies and find the ones you believe have the best temporal resolution and accuracy and are optimally located, then we have something to discuss. But regional and global reconstructions are worse than useless because they are misleading.
And, Briffa, 1998 shows exactly what I said. More details on Briffa’s work:
Briffa, et al. focus on maximum latewood density (MXD), which is typically a strong proxy for summer temperatures, as it reflects late-season wood formation influenced by warmth.
The key finding is they identify a “divergence” in the 20th century—starting around the mid-20th century (post-1950s), where the decadal-scale trends in MXD increasingly fail to track the upward trend in instrumental summer temperature records. Prior to this period, from the late 19th century through the mid-20th, the MXD series show strong coherence with temperature data when averaged over large regions (e.g., northern Eurasia and North America) and hemispherically. This coherence validates MXD as a reliable proxy for reconstructing past temperatures on broad scales. However, in recent decades, MXD has progressively declined even as temperatures have risen, indicating a reduced sensitivity of tree growth to temperature forcing.
The authors emphasize that this divergence is not uniform across all sites but is evident in aggregated, large-scale datasets. They note that ignoring this issue in paleoclimate reconstructions could lead to overestimating past temperatures, as the proxy would underrepresent modern warmth if calibrated solely on earlier periods of strong correlation.
The paper states that the reason for this reduced sensitivity is unknown but speculates on several possibilities, explicitly including anthropogenic factors proportional to rising atmospheric CO2 levels. These include CO2 fertilization effects (which could enhance growth independently of temperature) or improved water-use efficiency in trees under elevated CO2, decoupling growth from temperature controls. Other hypothesized factors mentioned are temperature-induced moisture stress, changes in winter snowfall patterns, or damage from increased UV-B radiation due to ozone depletion. The paper does not pinpoint a single cause but highlights that the phenomenon appears widespread.
The paper clearly documents the divergence between tree-ring density proxies and instrumental temperatures in the 20th century and lists additional CO2 as one plausible contributing factor among others. This “divergence problem” has since been explored in depth in subsequent research (e.g., D’Arrigo et al., 2008, Global and Planetary Change, doi: 10.1016/j.gloplacha.2007.03.004).
In short no one knows exactly why tree rings do not work well over at least half the instrumental record, but it is real divergence. It is probably related to additional CO2, and as figure 2 points out, tree rings are not helpful in reconstructions because you never know when they are accurate and when they are inaccurate.
“Showing, in my opinion, they are useless.”
That’s better than to say that Briffa proved what appears to be your sole opinion, Andy. Or worse that data themselves prove anything. They don’t: people prove things. A proof is a construction, and like other kinds of demonstrations they rely on people to be recognized as such.
And no, Briffa & al, 1998 doesn’t prove what you say. That’s not what the authors do at all. They in fact address the problem *you* consider fatal.
And beware that there’s more than one “Briffa & al, 1998”, e.g.:
https://www.nature.com/articles/35596
In that paper too the problem is being addressed!
Besides, what’s your argument here: because tree rings suck, reconstructions bad? As Spock would say: that’s, like, illogical.
None of that really seems to matter to you. You just say “Briffa”, the name of your favorite Mike (as if they saw eye to eye), and your frens became overexcited like it’s shark bait.
If you think it’s “data science”, you’re deluding yourself. It’s just very rudimentary Climateball. Pure theater to reinforce your and other contrarians’ prejudices.
Tree rings are very poor proxies, that is well established by Briffa, D’Arrigo, and others. If used one must be very careful.
But they are not the reason reconstructions are bad. They are bad because combining proxies reduces their resolution, both the temporal and temperature resolution. Combining them eliminates short-term spikes. What is short term? Depends on the reconstruction, but for common reconstructions (like the Kaufman reconstruction used in AR6 for the Holocene) that would be any warming or cooling event that was less than around 330 years (164 years x 2) (Kaufman, 2020, Holocene global mean surface temperature, a multi-method reconstruction approach, Nature, doi: 10.1038/s41597-020-0530-7).
For something like PAGES 2K, resolution is a bit better, but still it would wipe out any warming or cooling event with a duration of less than 40 or 50 years.
As usual a long, poorly written, insulting, and barely coherent comment that says almost nothing and has no substance. Are you drunk commenting? Exactly what is your problem?
Briffa did not “prove” anything. He simply showed the divergence between tree ring proxies and instrumental temperatures post 1950. This problem is well known and not controversial.
And yes, Briffa and team did publish another paper in 1998, but it is on volcanos and not divergence. Anyway, my bibliography for this post identifies the paper I was referring to precisely, sorry if you were confused, but it seems you often are.
“They are bad because combining proxies reduces their resolution, both the temporal and temperature resolution.”
In your own writing you emphasize the value of high-resolution Greenland ice cores:
“We often hear that the planet is warming faster than ever before, or at the fastest rate since the beginning of the industrial era! Is it true? We haven’t had thermometers for very long. How do thermometer readings compare to temperature proxies like ice cores and tree rings? Greenland is a good place to start, we see the high resolution Greenland ice core temperatures all the time. How accurate are they? How do Greenland temperatures compare to temperatures elsewhere?”
https://andymaypetrophysicist.com/2021/05/01/a-review-of-temperature-reconstructions/
That’s why I find it confusing that a high resolution High-Arctic ice core record like Lecavalier is dismissed rather than evaluated on the same basis.
I don’t dispute the accuracy of the ice cores, they do a decent job at the location they were taken with an accurate elevation history. The problem with Lecavalier’s analysis is not the ice core data, it is that his Huy3 model doesn’t work. I’ve made this clear before, let’s not go over old ground again. See Strunk(2018) and Martin(2024).
The Innuitian elevation correction only materially affects the early Holocene. It has no almost bearing on the late Holocene portion of the Agassiz record.
In the mid to late Holocene (the last 7–8 kyr) the reconstructions are nearly identical. That means the claim that modern temperatures are the warmest in the past 6,800–7,800 years is drawn from a part of the record where the two reconstructions agree, and is not undermined by the early Holocene adjustment:
They do not agree for the past 7-8kyr, only for the last 2kyr. The difference in the proxies at 6ky is at least 2-3 deg. Compare to my figure 1 in the post.
I think we are talking past each other. My comment refers specifically to Lecavalier Fig. 1B, which compares Agassiz ice core reconstructions Vinther (blue) vs Lecavalier (red).
After ~7.5 ka they track each other closely, with differences generally well below 1 °C and within uncertainty. I don’t see a persistent 2–3 °C offset at ~6 ka in that figure
Your Fig. 1 introduces Rosenthal Strait, which is a different proxy and not part of that comparison.
I suppose, if you take Agassiz as ground truth, which I would argue with.
There are many Greenland proxies, and they are difficult to reconcile. Lecavalier tried and kudos to him for trying, but his model is flawed.
Attached is a plot of three of them and their average in blue for the past 4,000 years. Ignore the European Dark Age from 600AD to 800AD, that was climatic chaos. The rest of it compares fairly well to about 0AD, then it is a mess. Before 2000BC it is even worse, really ugly.
So, I will grant you to 0AD the comparison is acceptable, except for the European Dark Age, but not before 0AD.
“I suppose, if you take Agassiz as ground truth, which I would argue with.”
For Lecavalier’s analysis, it is the most directly relevant site.
Agassiz is located in the High Canadian Arctic and is strongly influenced by Arctic Ocean and sea ice conditions, whereas central Greenland proxies (your graph) reflect a different climatic regime.
This is a bit ironic to point out. Elsewhere (February 6, 2026 10:26 AM), you noted a preference for examining multiple proxies from a single location together, presumably to ensure internal consistency:
“Still true, but he is referring to a collection of proxies from Greenland ice cores. I like examining individual proxies from one location all together, see here:”
You write:
See attached figure 1 from Vinther, 2009. Remember “Agassiz” is not that one core, it is a combination of Agassiz and Renland clear across the island, they have similar histories and well-defined elevation histories which is why Vinther chose them. When I say “Vinther reconstruction” I mean just that, it is a reconstruction based on both proxies.
The six ice cores Vinther used are shown in the middle graph, these are all carefully synchronized in the time dimension, yet their profiles are very different. Only Agassiz and Renland are similar.
Thus, Vinther is still the best Greenland reconstruction for air temperature, but it is not just one proxy. It does not tell us about the whole Arctic, but it is good for Greenland. Lecavalier tried to take what Vinther did farther by using his model, it just didn’t work.
You didn’t really ask a question, but these are my comments. I still like comparing proxies from the same location, which is what Vinther does, and does well. I’m also happy comparing his reconstruction to Rosenthal’s, which is also based on comparing a lot of proxies in the Makassar Strait. I hope that clarifies my position somewhat. I just think working locally on relatively small regions is best. By small regions I mean the size of Greenland and the Makassar Strait. I’m not happy with any reconstruction of the whole Arctic or any hemisphere-wide reconstructions. I’m certainly not happy with any global reconstructions, my own included.
I’m still unclear on one point. You explicitly state that Vinther is a Greenland reconstruction and not representative of the broader Arctic.
Given that, I don’t understand why Vinther and Rosenthal are being used in this blog post to argue against the Lecavalier High Arctic result.
If we’re committed to a local perspective, then a High Arctic record should carry more weight for a High Arctic question than either a Greenland interior reconstruction or tropical marine proxies.
I think you have forgotten the whole point of the post was to argue that Lecavalier’s assertion that today is warmer than any period in the last 6,800 years in the Arctic was extremely unlikely and that his model doesn’t prove anything of the sort.
The reason I displayed Vinther and Rosenthal’s local reconstructions is that they establish that a strong Holocene Climatic Optimum exists until 6,000 ky BP in the Northern Hemisphere middle and high latitudes. These proxies are well located and very high resolution, which is why I like them.
The Arctic is a climatic mess, especially in winter, the proxy records (note all are reconstructions, but these are very local reconstructions which means they are OK with me) in the Arctic cover a span of +-2 deg in recent years and >+-3 deg in the early Holocene, as you can see here:
https://andymaypetrophysicist.com/2017/06/08/a-holocene-temperature-reconstruction-part-3-the-nh-and-arctic/
“High Arctic” is a misnomer for Lecavalier’s work, “Greenland area” is better. And remember Vinther looked at all the Greenland proxies and chose two, one of which is not even in Greenland to use for his Greenland area reconstruction. Neither have any proxies from Alaska or Siberia which have very different climates.
Vinther’s Greenland reconstruction has stood the test of time and is very robust. Lecavalier’s is weak, mainly because of his model, but even if Lecavalier were correct, it is not an Arctic reconstruction, but a Greenland area reconstruction just like Vinther’s, but it needs a lot of work.
Make sense? I want to craft better language, just using the words proxy and reconstruction doesn’t cut it. They are all reconstructions, but I am recommending local reconstructions and dislike global or hemispheric reconstructions. Averaging local proxy records in one climatic regime region (eg. Greenland) makes some sense, when you cross into multiple regimes (eg. Arctic) it makes much less sense. Climate is a regional thing.
For the Arctic proxies you show in your post, I don’t see fundamental disagreement in the large scale Holocene pattern.
Aside from differences in the timing and amplitude of early deglaciation warming, they broadly show a Holocene Climatic Optimum followed by long term cooling consistent with orbital forcing (which is also what Lecavalier shows).
In that sense, I’m not convinced that proxy spread alone is a strong argument against Lecavalier’s conclusion, since much of that spread reflects the expected locality of the records, as you note.
Where Vinther and these proxies differ materially from Lecavalier is mainly in the early Holocene (∼12–7.5 ka BP) and in the modern blade.
The early-Holocene difference has little bearing on Lecavalier’s claim that recent temperatures are the warmest in 6,800–7,800 years, because that interval lies almost entirely after the period where the records diverge. As for the modern blade, Lecavalier explicitly constrains it using nearby instrumental observations.
I also disagree with the characterization of Lecavalier as essentially a “Greenland area” reconstruction.
Instrumental data show that Greenland and the High Arctic have behaved very differently in recent decades.
Greenland interior temperatures have shown relatively no warming since ~2000, whereas the High Arctic has warmed rapidly. See my comment dated February 3, 2026 6:22 AM.
Using instrumental data from Ellesmere Island (the location of the Agassiz Ice Cap), I calculate a warming rate of roughly 0.62°C/ decade from 2000–2025, which is more consistent with High Arctic amplification than with Greenland interior behavior.
That observational context supports interpreting Lecavalier as a High Arctic record, not merely a Greenland area one.
True, as long as by late Holocene you mean after 0AD. And don’t confuse reconstructions using multiple ice cores, and individual proxies with well-known elevation histories like Vinther’s.
Lecavalier handles his ice cores separately, which is laudable. He tries to correct them for elevation changes through time and determine a history for the whole island. This is useful; however his model is suspect, thus the temperature history is also suspect.
I like his ideas, but his conclusions do not draw from his work, and they are falsified by other data and research. Not uncommon in climate science.
“True, as long as by late Holocene you mean after 0AD.”
That claim is patently false.
The Innuitian Ice Sheet was largely gone by ~8–7 ka BP, so by 0 AD it had been absent for several millennia.
Redefining “late Holocene” as “after 0 AD” is nonstandard and chronologically wrong. In Quaternary terminology the late Holocene begins several thousand years before 0 AD.
Normally the late Holocene is taken as the SubAtlantic chronozone (2.5ka BP to the present). But there is no formal definition of “late Holocene” that I’m aware of, thus I was specific. “Several thousand years” before 0 AD is the Mid-Holocene transition from the Holocene Climatic Optimum to the Neoglacial.
“In July 2018, the International Union of Geological Sciences split the Holocene Epoch into three distinct ages based on the climate, Greenlandian (11,700 years ago to 8,200 years ago), Northgrippian (8,200 years ago to 4,200 years ago) and Meghalayan (4,200 years ago to the present), as proposed by the International Commission on Stratigraphy.[7] The oldest age, the Greenlandian, was characterized by a warming following the preceding ice age. The Northgrippian Age is known for vast cooling due to a disruption in ocean circulations that was caused by the melting of glaciers. The most recent age of the Holocene is the present Meghalayan, which began with extreme drought that lasted around 200 years.[7]”
https://en.wikipedia.org/wiki/Holocene#:~:text=In%20July%202018%2C%20the%20International,by%20the%20melting%20of%20glaciers.
And this was the main point, by the way:
The Innuitian Ice Sheet was largely gone by ~8–7 ka BP, so by 0 AD it had been absent for several millennia.
What is the significance of that, I don’t get it.
The significance is straightforward. The Innuitian Ice Sheet was largely gone by ~8–7 ka BP, so any elevation correction issue tied to its thinning is confined to the early Holocene. By the time you get to the last 6,800–7,800 years, that mechanism no longer exists.
So invoking the Innuitian elevation correction to cast doubt on Lecavalier’s late Holocene / modern High Arctic temperature conclusion is simply irrelevant.
Whatever one thinks about early Holocene adjustments, they have no bearing on the conclusion that recent High Arctic temperatures are the warmest of the past ~6.8–7.8 kyr.
That’s the point.
I see what you mean, do you have a map of the Innuitian Ice Sheet? I don’t want to go back to ground zero, this is ground already covered by Vinther but just doing due diligence.
“I see what you mean, do you have a map of the Innuitian Ice Sheet?”
I’m not sure why the precise geometry of the Innuitian Ice Sheet is central here.
Your claim seems to be that the elevation correction model used by Lecavalier invalidates the paper’s conclusions, but I don’t see that as a strong argument.
Examining the chronology, Vinther and Lecavalier diverge only in the early Holocene, which coincides with the presence and thinning of the Innuitian Ice Sheet. Once that ice sheet is gone, the reconstructions converge.
That is exactly what you expect if the elevation correction is doing what it’s supposed to do, and only when it’s supposed to do it.
All Lecavalier presents is a graph (his figure 4), I wanted to see a map because Vinther relies on Agassiz and Renland for his reconstruction of Greenland temperatures, they are very similar. Lecavalier is very vague about the data portrayed in the graph, but I think he is only talking about the NW Greenland near Agassiz. Renland, with a similar history is in eastern Greenland in a separate basin. See attached map from Lauritzen, et al., 2025, Cryosphere.
https://tc.copernicus.org/articles/19/3599/2025/tc-19-3599-2025.pdf
I don’t think your hypothesis holds up, see the attached reconstruction of bedrock deformation in Greenland. The Innuitian Ice Sheet seems unrelated to either Agassiz or Renland. This a complex area during the Holocene and we are getting pretty far into the weeds. Bottom line: Lecavalier has been challenged by two subsequent papers (Martin and Strunk). Vinther provides a different interpretation that is well accepted, I think we should go with Vinther.
Doesn’t matter much anyway, nearly all the data for the Greenland area and the North Pacific region points to the temperatures prior to 0AD being higher than today anyway. Glacier advance data says that nearly the whole globe was warmer than today prior to 0AD. Lacavalier has a long way to go to prove his point.
“The Innuitian Ice Sheet seems unrelated to either Agassiz or Renland.”
The Innuitian Ice Sheet unquestionably covered Ellesmere Island in the early Holocene, which is why Agassiz experienced large early-Holocene elevation changes.
Renland, by contrast, was never influenced by Innuitian ice. That asymmetry is exactly why early Holocene differences between the records are expected, and why those differences (between Vinther and Lecavalier reconstructions) disappear once Innuitian ice is gone.
Good points. I don’t agree, but only time will tell. These issues are very hard to resolve, too much uncertainty.
From Lecavalier:
“Over the early Holocene, Innuitian ice thinned by ∼400 m along southeast Ellesmere and so dominates the altitude correction. In contrast, the mid to late Holocene correction is dominated by GIA of ∼100 m (Figs. S2 and S3).”
I remember that. I don’t know anyone who uses those terms, they make absolutely no sense from either a historical or geological perspective. The so-called “Meghalayan” is based on the 4.2kyr event, but it sits in the mid-Holocene transition, in the middle of the Bronze age, a thousand years before a very important climatic event, the end of the Bronze Age and the beginning of the Greek Dark Age. It makes no sense. We had best avoid using terms like the “Late Holocene.” Stick to dates.
Basically, the issue is this:
Fig. 4B shows the model failure is confined to the early Holocene.
But, if you don’t trust the model, then compare Lecavalier directly with Vinther (which is independent of the model) and note where the two reconstructions converge. Either way, the late-Holocene and modern parts of the record are unaffected.
“And yes, Briffa and team did publish another paper in 1998, but it is on volcanos and not divergence”
Andy, meet Andy:
Source: https://www.ncei.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/nhemtemp_data-noaa.txt
It’s the second time I read the first line of your own citation to you.
Please try not to make it an habit.
?? Again you make no sense. Are you incapable of writing clearly?
Here is the bibliography entry in this post:
Briffa, K., Schweingruber, F., Jones, P., Osborn, T., & Vaganov, E. (1998b). Reduced Sensitivity of recent tree-growth to temperature at high latitudes. Nature, 678-682. Retrieved from https://www.nature.com/articles/35596
Seems clear to me, maybe you have trouble reading?
I’m sorry I’m so unclear, Andy.
Here is the publication you alluded to –
Source: https://www.ncei.noaa.gov/access/paleo-search/study/6224
That’s one Briffa et al. 1998. Here is the publication I cited earlier –
Source: https://www.nature.com/articles/35596
That’s another Briffa et al, 1998. Does “beware that there’s more than one “Briffa & al, 1998” make more sense, now?
As for the divergence problem, we should also bear in mind that:
Source: https://www.st-andrews.ac.uk/~rjsw/papers/Buentgenetal2009.pdf
None of that matters for the point you try to dodge, i.e. the main reason you mention “Briffa” here is as chum for your Climateball audience.
Hence the long stream of consciousness that goes from Lecavalier to Rosenthal, Vinther, Kaufman, orbital cycles, Greenland, Briffa, your favorite Mike, CG I (there is II and contrarians tend to forget III), the divergence problem, Milankovitch cycles, back to your Climate History that is not really a reconstruction, it’s just two data series.
I mean, come now.
The only Briffa paper I “alluded to” is:
Briffa, K., Schweingruber, F., Jones, P., Osborn, T., & Vaganov, E. (1998b). Reduced Sensitivity of recent tree-growth to temperature at high latitudes. Nature, 678-682. Retrieved from https://www.nature.com/articles/35596
Straight from the bibliography for this post. If you think that there is no divergence problem, then you disagree with a lot of people, but you are allowed to do that. Your paper (Büntgen, et al.) is not very impressive and pretty inconsistent. They seem to say, well there is a divergence problem, but maybe we can find a way around it. Pretty weak stuff. They also present no data contradicting Briffa, 1998 or D’Arrigo et al.
Oh, Andy. Let me quote you, then:
This is one of the “Briffa & al, 1998”. The hint is in the very first line of that file: I read it twice to you already. This Briffa & al is not the one we have in your bibliography, but it is the one you mentioned to me. Either you still don’t realize it’s one of the Briffa & al, 1998, or you’re just playing the hard of hearing.
Speaking of weak sauce, I note your “they seem to say”. Again with the half-baked fluff! How can you evaluate a report with “they seem to say”? Read harder. Then report what they say!
Finally, the Briffa & al 1998 you cite in your bibliography doesn’t say what you make them say. They’re not saying that tree rings are useless. They’re saying there’s a problem, and discounting divergence can overestimate past temperatures. One way to sidestep it is just to cut the series when it diverges, which is why Mr. Nice’s insistence that we use contemporary tree rings is beyond silly.
Anyway, none of this is relevant to your point, which ought to be about Greenland. You just mentioned Briffa and your favorite Mike because of what we could call contrarian conditioning. When a contrarian hears “reconstruction”, expect “but tree rings”, “but MBH”, “But CG”. The usual rigmarole.
The irony in Andy invoking the Briffa divergence problem is that his Kaufman composite, which explicitly excludes tree rings, still fails to capture the variability of the last half century accurately.
It is not my Kaufman composite, I don’t even like it. I don’t make composites anymore.
Willard,
Now you are being weird.
Your quote from me is from a comment where I showed a link to Briffa’s reconstruction, followed by a link to some data he gathered to show that there is some Briffa data. It was in a response to your comment:
Where you claimed there was no Briffa data.
I was merely pointing out there was some Briffa data, both a reconstruction and some original data. How on Earth you now claim I cited the wrong Briffa, 1998 paper because of that, is beyond comprehension. Get in the game man! Be clear and cite exactly what you are referring to.
My Briffa paper is clearly cited correctly in the bibliography, get over it.
As for tree rings, they are useless after 1950, I think that is well established. They also cannot be calibrated to modern instrumental temperatures after 1950. As I’ve said before if they are used, they must be used very carefully, and individually, not combined. When used, the calibration must also be shown. I don’t think I’ve ever said anything different, unless I misspoke or it was in a different context.
Personally, I don’t use them at all, they are too unreliable. I prefer well located ocean and ice core proxies.
That’s the paper Andy cited in his post.
Exactly, Willard has a serious reading comprehension problem and doesn’t explain himself very well.
Andy,
You’re just being obtuse to evade a very simple point.
The “link to some data he gathered to show that there is some Briffa data” is yours. You introduced it here:
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4163099
That is not “some data”, that’s the file you yourself cited!
Check again the first line of that file:
Briffa et al. 1998 Northern Hemisphere Temperature Reconstructions
Notice anything?
The point you’re trying to evade by being obtuse is that you’re just throwing the word “Briffa” around as red meat for your coterie.
Tree rings have nothing to do in your post.
Please, do try to be obtuse again. Let’s see if you’ll succeed in making me forget to make my point.
Willard,
That, by far, is your weirdest comment ever. You wrote that there is no such thing as any “Briffa data” in response to bnice. I simply pointed you to two repositories of Briffa’s data, that’s it. One of my examples was a reconstruction he did and one was data he gathered, that was the whole point, no big deal.
You were clearly wrong that there is no Briffa data, why not just drop the subject. Here is a link to your erroneous comment that I was simply correcting:
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4162829
You said, erroneously:
Are you kidding me, Andy?
It is impossible that you still don’t realize what “et al” means! It means it’s a collective effort! You can’t pretend that it’s the first author’s product!
Besides, let’s put the two “Briffa et al. 1998” side to side:
(1) Northern Hemisphere Temperature Reconstructions
(2) Reduced Sensitivity of recent tree-growth to temperature at high latitudes.
(Again – notice the plural in (1): reconstructions. There are many!)
See? Two “Briffa, with all the others, 1998” that you should not conflate. Just like what I said!
Why did you write “1998b”, BTW – do you have a 1998a in your bibliography? Don’t tell me you don’t know when to add letters to a date!
Besides, here is the graph Mr. Nice posted:
Source: https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4162693
Do you have any idea how silly this “Briffa Tree data” is?
Go ahead, try to replicate that “reconstruction”! Don’t forget to publish your code and your data, with robust provenance. That is, everyone should be able to trace everything back to Briffa himself. Pretty please with sugar on it.
All this to say “Briffa” in a piece that doesn’t involve tree rings.
What a joke.
“The hockey stick is FAKE. Must be from a Mannian disciple.”
Translation: “This threatens my worldview, so I must discredit it at all costs.”
That much is obvious from reading bnice’s posts. If he cares about posting accurate information, why isn’t he consistent in his posts?:
I get why some people are desperate to discredit Lecavalier’s chart. It is alarming, and uncomfortable facts tend to provoke that reaction.
Under a slower, more natural warming episode, Arctic species probably would be able to adapt. But this warming is so steep it’s hard not to be concerned. What do their populations look like in 2150? : – 0
We don’t need to discredit Lecavalier’s chart, he and Martin are doing just fine.
In response, I refer to my February 3, 2026 9:08 am comment on the other thread.
My reply on Lecavalier, et al. (2017):
The paper makes some interesting points, especially their speculation on the migration of the warming across Greenland. But their Huy3 model is flawed, which invalidates their conclusions.
Sites like Agassiz, near the Greenland Ice Sheet margins, may overestimate HCO (Holocene Climatic Optimum) warmth due to elevation-driven cooling during ice buildup or warming during retreat. For instance, Kaden Martin et al.’s 2024 study on Greenland ice cores notes that marginal records can be “overprinted” by such effects, leading to discrepancies with central sites like GISP2 and NEEM.
Lecavalier’s corrections (using lapse rates of ~7°C/km) are applied, but later work suggests these may underestimate variability, implying the HTM temperature peak could be less extreme or differently timed regionally. Similarly, a 2018 (Strunk, 2018, doi: 10.3389/feart.2018.00129) study on North Greenland RSL argues that the Huy3 model (co-developed by Lecavalier) underestimates LGM ice thickness, suggesting the GrIS was thicker and more extensive, which could alter Holocene temperature interpretations.
Thus, while an interesting paper, Lecavalier’s conclusions are very suspect. Look closely at figure 9 in Strunk et al. The range of elevations from 12,000 yrs ago to 2,000 years ago is over 10,000 meters above mean sea level. With that much uncertainty in elevation, the temperature estimates are of no value.
Strunk’s point is that the ice melt in Greenland was extremely fast (geologically speaking) and hard to model.
Strunk et al.:
https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2018.00129/full
Lecavalier’s chart is DESTROYED by other data… get over it. !
Polar bear populations are growing, FAT and HEALTHY.
Holocene has been MUCH warmer, but there are still lots of polar bears.
Your Nostra-dumb-ass type prophecies are hilarious. 🙂
—
Before 1900, there was much lower CO2 levels..
Do you DENY that fact…
… or are you just totally unaware that trees need CO2 to grow properly.
“Before 1900, there was much lower CO2 levels..
Do you DENY that fact…
… or are you just totally unaware that trees need CO2 to grow properly.”
I’m pointing out that you rely on tree ring proxies when they support your position. That inconsistency is hard to ignore.
I only presented tree data after 1900, when there was enough CO2 to allow some tree growth.
You have basic comprehension issues, don’t you.
You also presented paleoclimate data that exclude tree ring proxies. Tree rings are problematic for capturing low frequency variability in proxy reconstructions both before and after 1900, due to factors besides CO2. As such, they appear to be treated as supportive when convenient.
Sorry, this response of mine is incoherent.
Let me resubmit a better reply:
“I only presented tree data after 1900, when there was enough CO2 to allow some tree growth.”
Tree rings are poor proxies for capturing low frequency variability, and this limitation applies to the post 1900 period as well.
At least in the region around Svalbard.
“Under a slower, more natural warming episode, Arctic species probably would be able to adapt. But this warming is so steep it’s hard not to be concerned.”
Please explain how polar bears survived temperatures 8C warmer than today during the Holocene Thermal Optimum? Did you allow your heart strings to be manipulated by a picture which replaced reason?
How a temperature anomaly develops is biologically important, not just its absolute magnitude.
Fauna and flora most likely can adapt more successfully to slow, gradual climate changes than to rapid shifts.
Given the speed of contemporary temperature change in the High Arctic, some level of concern for ecosystems there is entirely reasonable.
Arctic sea life is actually starting to return to the Arctic as it recovers from way too much sea ice in the LIA and around 1979.
Only temperature change in the Arctic this century is related to the 2016 and 2023/4/5 El Ninos
“Fauna and flora most likely can adapt more successfully to slow, gradual climate changes than to rapid shifts.”
All species are highly adapted to far greater extremes than the worst climate projections. You are not thinking reasonably or rationally.
If you are referring to regular seasonal and daily extremes, that is not in dispute.
But tolerance to cyclical variability isn’t the same thing as adapting to a rapid, directional shift in baseline conditions.
The ecological consequences of the latter seem less certain.
Polar bear populations may persist, but a substantial reduction in sea ice relative to today could significantly change their habitats, hunting patterns, etc.
Attention – goalposts in movement! Now, it’s the rate of change, not the actual temperature, which is the villain of the piece…
Your difficulty in following the discussion is noted.
The changes you speak of occur so slowly (~1 degree/century) I doubt any species will notice it.
According to your methodology (waiting for at least 100 years of data rather than extrapolating), the rate of temperature change in the High Arctic is approximately 2.5 °C/century.
Andy,
I think something that many people, including geologists, don’t appreciate is the role that orogeny plays in evolution by creating new ecosystem niches resulting from the lapse rate. Inversely, many of those ecosystems are closed off by erosion and peneplanation.
“But tolerance to cyclical variability isn’t the same thing as adapting to a rapid, directional shift in baseline conditions.”
There is no “rapid” shift in baseline conditions happening. Most latitudes above 35 degrees experience 100F+ swings annually. The gradual 2F increase since the little ice age is nothing compared to that.
“Polar bear populations may persist, but a substantial reduction in sea ice relative to today could significantly change their habitats, hunting patterns, etc.”
The data shows they do better with less ice.
“There is no “rapid” shift in baseline conditions happening. Most latitudes above 35 degrees experience 100F+ swings annually. The gradual 2F increase since the little ice age is nothing compared to that.”
Yes, according to Lecavalier there is. And see my comment directed to Andy May on February 6, 2026, at 7:10 AM.
“The data shows they do better with less ice.”
There’s a big difference between modest ice reduction and a rapid shift from perennial to seasonal sea ice.
“according to Lecavalier there is”
Do you have the ability to think for yourself? Annual variations are almost an order of magnitude larger than the gradual temperature increase the last 150 years. All species adapt to those extremes just fine.
You dodged the question about how polar bears survived temperatures 8C warmer than today? Seasonal Ice was all that was present then.
“Do you have the ability to think for yourself? Annual variations are almost an order of magnitude larger than the gradual temperature increase the last 150 years. All species adapt to those extremes just fine.”
It is not a gradual increase.
“You dodged the question about how polar bears survived temperatures 8C warmer than today? Seasonal Ice was all that was present then.”
I never disputed that polar bears survived when it was 8°C warmer. The issue is the rate at which we reach that temperature anomaly and seasonal sea ice threshold.
Do you expect the biosphere to be static over all time now that we have achieved the optimum? /s
True, seasonal and diurnal changes in climate far exceed anything we have seen over the past 170 years.
That statement is only true if one compares mean climate change directly to seasonal or diurnal variability, which isn’t the relevant comparison.
However, important points are being overlooked:
Seasonal and diurnal variability is predictable and cyclic. Organisms are adapted to these repeating patterns, not to persistent shifts in baseline conditions.
A change in the mean shifts the entire distribution. As average temperatures increase, the full temperature distribution moves, amplifying warm extremes and likely affecting ecosystems.
Diurnal and seasonal variation is the more important because it is freezing that kills plants and extreme temperatures that kill animals.
What you and gyan1 are missing is that seasonal and diurnal extremes are important, but they are also predictable.
That predictability is exactly why plants and animals survive them. Seasonal cues allow organisms to retreat or prepare in advance before lethal cold arrives.
A rise in the mean temperature changes something fundamentally different: it shifts the entire temperature distribution, which makes warm extremes more frequent.
This matters a lot during autumn freeze up in the Arctic. Warmer autumn extremes can delay sea ice consolidation, even if winter eventually becomes cold. For polar bears, delayed freeze up reduces access to seals and extends the fasting period (Jul – Nov).
https://polarbearsinternational.org/news-media/articles/polar-bear-eating-habits-fasting-periods
“you and gyan1 are missing is that seasonal and diurnal extremes are important, but they are also predictable.”
You are missing that climate change is a primary evolutionary driver of resilient species. They all are highly adapted to a much broader range of temperatures than the worst climate models project.
However,Important points are being overlooked:Pure speculation. Facts please.
All a pika or snow leopard has to do is migrate upwards about 30 meters per year to maintain a similar climate, or if the upward migration path is cut off, migrate to the north side of a mountain, which is the last refuge for alpine glaciers.
Eventually, even with no change in sea level climate, alpine-adapted plants and animals will become extinct if they don’t adapt to a warmer climate as erosion reduces the elevation of a mountain range.
in your fantasy, if nowhere else.
Unfortunately, adding CO2 to air does not make thermometers hotter, which makes Mann’s posturings the acts of a dingaling disconnected from reality.
Mann is a demonstrated faker, fraud, scofflaw and deadbeat. That says nothing about his scientific achievements, but he’s also ignorant and gullible, which does. It’s obvious why you choose him as your role model.
Andy, my comment is in moderation. Stay tuned.
“everything in moderation” is good practice 🙂
No, “everything” is being excessive. That should be ‘most’ things. 🙂
I freed it from jail, see above.
Several data graphs still refusing to show up.
I tried to free them up, they should show up now.
The Sahara was a grassland with lakes until about 5000 years ago. Is there a cause and effect between that and the end of the Holocene?
The Holocene is still ongoing. I assume you mean Holocene Climatic Optimum.
if so, the answer is yes, the Wet Sahara is attributed to the same causes as the HCO.
yes
True
Remains of forests being found under retreating glaciers.
Glaciers that probably didn’t even exist until the LIA… and are still there.
We are still very much at the COOLER end of the Holocene interglacial.
WE should all be very thankful for the slight warming we have had since the LIA.
So very much COOLER:
Source: https://www.rutgers.edu/news/important-climate-change-mystery-solved-scientists
How do you explain the existence of tree stumps in terrain which is now treeless tundra?
Yes, Tree Stump science refutes unprecedented warming claims for today’s temperatures.
We discover that trees could grow in places then, that they can’t grow in now, because it is too cold now. Therefore, it was warmer then than it is today.
Have you researched the question yourself, Graeme?
In the Arctic, current temperatures are likely still cooler than they were in the early Holocene. This is a different from the global average Holocene trend shown in Willard’s graph.
Correct. The illustration shown by Willard is from a very flawed paper by Samantha Bova and colleagues that has been heavily criticized by Laepple et al. and Zhang, et al. It has been heavily revised, but not retracted, at least not yet.
https://andymaypetrophysicist.com/2024/03/15/the-holocene-climatic-optimum-and-the-pre-industrial/
Here is an image of a fossil tree stump in permafrost on Ellesmere Island.
How convenient that there is no labeling for the vertical axis.
Bova’s 2021 paper was deeply flawed . I don’t think it was completely retracted, but it has been updated and flagged as incorrect. See “Matters arising.” More here:
https://andymaypetrophysicist.com/2024/03/15/the-holocene-climatic-optimum-and-the-pre-industrial/
This is a complex subject. The short answer is it is a function of obliquity and precession at its root. But the immediate cause of the change from savannah to desert was a movement of the average ITCZ latitude to the south around 5.9kyr BP.
See the ODP-658C proxy record shown in figures 9&11 in this post:
https://andymaypetrophysicist.com/2017/06/06/a-holocene-temperature-reconstruction-part-2-more-reconstructions/
A map of the core’s location is in figure 10 and a link to deMenocal’s paper on the core is below figure 10.
An illustration of the ITCZ movement, relative to the location of ODP-658C is shown in figure 12.
The timing of this move falls between the Holocene Climatic Optimum and the Neoglacial during a period called the Mid-Holocene transition.
Using GISP Greenland temperatures , there are multiple period of warming and cooling that are at least as steep and for much longer periods that the recent paltry warming tick.
“ that the recent paltry warming tick.”
Which extends beyond the 19th century whereas your graph ….
does not.
Mickey Mann’s hockey stick shows the base of the up tick is around 1900.
The end of the uptick is around 1940.. Greenland is no warmer now than in the 1940’s
“Junk science” is Mr. Nice middle name.
HadCrut1 was from the 90s. HadCrut2 was first published in 2003. Even HadCrut5, from 2020-21, is getting old:
https://www.metoffice.gov.uk/hadobs/hadcrut5/
Since I have been challenged to provide a graph:
Source: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JD032361
When there’s no uncertainty range, it’s junk science. Mr. Nice is allergic to uncertainty.
Mickey Mann’s Hockey stick shows the base of the small spike is 1900..
The peak is in 1940.
As shown elsewhere, the temperature is now similar or cooler than 1940.
You don’t reject data because it does not match your assumptions and hypothesis, it only works the other way around. You explain the data (observations) with your hypothesis and assumptions, or you reject them.
“Or” is symmetrical.
I find it very intriguing that the Makassar Strait water temperatures from Rosenthal, et al, show a warming spike around 700 AD that was warmer than the 1000 year spike. It matches the Kobashi proxy.
Cool, I never noticed that. I compare Kobashi with Vinther here:
https://andymaypetrophysicist.com/2021/05/01/a-review-of-temperature-reconstructions/
That period from 500 to 800AD must have been a mess in the Northern Hemisphere, the proxies are all over the place and there was a solar grand minimum (SGM) at ~670AD right in the middle of the European Dark Age. I suspect there was a very cold period in the middle 600s, then a warm spike around 700AD, followed by an extreme cold period ~780. This is when a third of the European population died. Then it got warmer in the 800s and the Vikings nearly took over the western world.
The Little Ice Age is like that, extreme cold followed by extreme warmth, with lots of extreme weather.
But this is a guess. See here for the details I was able to dig out about the period.
https://andymaypetrophysicist.com/2024/12/02/climate-change-over-the-past-4000-years/
Erasing the past is something the climate alarmists need to do in order manufacture alarm. The Holocene Optimum is not the only example.
Mann’s hockey stick handle erased both the MWP and the LIA. Unfortunately for Mann, there is abundant contrary archeological and historical evidence.
The Arctic ice alarm ignored the ~60 year quasi-cyclical observed ice extent fluctuations recorded by DMI from first whaling and then fishing vessels as discussed by Akasofu in his 2010 paper.
And on the shortest time frames, Lindzen observed about 2011 that the warming from ~1920-1945 is visually and statistically indistinguishable to that from ~1975-2000. Yet even IPCC AR4 SPM (figure 4) said the former could not be attributed to CO2. Yet the climate alarmists still claim natural variation is de minimus.
That the rate of warming of two distinct periods of atmospheric CO2 concentration is indistinguishable should be a big clue.
Definitive, I would say.
“And on the shortest time frames, Lindzen observed about 2011 that the warming from ~1920-1945 is visually and statistically indistinguishable to that from ~1975-2000. Yet even IPCC AR4 SPM (figure 4) said the former could not be attributed to CO2. Yet the climate alarmists still claim natural variation is de minimus.”
Incorrect, Rud.
https://tamino.wordpress.com/2019/01/23/hot-and-cold-curry/
Relying on Tamino is a mistake. I published years ago here in a single post the actual data, the Lindzen citations, and the AR4 SPM figure 4. Go look that up and get back after informing yourself of the actual facts.
Tamino is one of the VERY LAST place to go for anything to do with climate science.
A rabid and twisted AGW zealot. Perfect for baseless propaganda, though..
Tamino is a propagandist who took Curry out of context to defame her. It’s the slope of early 20th century warming that is almost identical to the slope of modern warming which has continued longer.
He uses pathetic emotionalism to dupe the easily manipulated. –
Open Mind“KIDS’ LIVES MATTER so let’s stop climate change”
From NASA GISS data:
https://data.giss.nasa.gov/gistemp/graphs_v4/
The rate of warming from 1920–1945 is 0.17 °C/ decade, while the rate from 1975–2000 is 0.16 °C/decade, so Rud is correct on that point.
However, if we move the window forward to 2000–2025, the warming rate increases to 0.26/C per decade.
“He uses pathetic emotionalism to dupe the easily manipulated. –”
And what about this?:
“The world’s most viewed site on global warming and climate change”
So you’re contesting the viewership monitoring of websites traffic that all advertising companies use in deciding where to place their clients’ digital presence?
Geez, what a multiple business disciplinarian you must be.
“However, if we move the window forward to 2000–2025, the warming rate increases to 0.26/C per decade.”
The current rate according to UAH is 0.16C per decade.
“The world’s most viewed site on global warming and climate change” comes from measured metrics.
“KIDS’ LIVES MATTER so let’s stop climate change” is pathetic emotional pleading that only the easily duped would fall for.
“The current rate according to UAH is 0.16C per decade.”
But that refers to the lower troposphere, which has no data prior to 1970 for comparison with early 20th century warming. For consistency, we therefore rely on surface temperature data.
Surface data from the Arctic
Iceland is under the Arctic circle, Mr. Nice.
We’ve already been over this:
https://andthentheresphysics.wordpress.com/2024/01/16/how-to-cavil-like-cranks/
Iceland was hotter in the 1930’s, than it is today.
Just like everywhere else on Earth.
2.. from around the Arctic
Source: https://arctic.noaa.gov/arctic-indicators/
GISS is manically adjusted and doesn’t look anything like any original data.
Ignore EVERYTHING from GISS.. they are one of the leaders of the AGW scam, and you will only remain grossly mal-informed.
Here’s one based on unadjusted raw data.
And from Jones (left) and Hansen (right
https://www.researchgate.net/publication/337767945_The_polar_regions_in_a_2C_warmer_world
“Temperature trends and variability for the Arctic and Antarctic regions. (A) Annual mean anomalies of the combined Land-Ocean Temperature Index (L-OTI) for the Arctic (64°N to 90°N), Antarctic (64°S to 90°S), and globe between 1880 and 2018 (zonal data bins defined by data acquired at https://data.giss.nasa.gov relative to the mean period 1951–1980). Temperature anomalies for the Arctic during each of the four IPYs, the first of which was based in the Arctic, are highlighted in purple. (B) Annual [January to December (J-D)] mean temperature change (°C) in the Northern (left) and Southern (right) hemispheres for 1986–2005 (upper) and 1986–2018 (lower) relative to the mean period of 1951–1980. Generated from the NASA/Goddard Institute for Space Studies (GISS) online plotting tool (2); the GISS analysis is based on updated Global Historical Climatology Network v3/SCAR (2, 3) and updates to Analysis (v3)”
Cue “faudulent”
and “no evidence” blah, blah (ie just the usual)
GISS.. roflmao.. based on the totally HORRIFIC surface sites that you so love in the UK.
Show us where land was measured before 1900, then up to 1940.
Show us where oceans were adequately measured before 2005.
Still waiting.
That’s called the Subarctic, Mr. Nice, and as Bender would say, “needles in the eyes”. Try this instead:
https://www.nature.com/articles/s41467-022-29677-8
GISS is based on junk surface sites. It is NOT REAL
And starting right in the depths of the LIA.. Hilarious.
You claimed the current trend was 0.26 per decade. That is not true. Changing the subject doesn’t make it so.
It is, when using surface data, which is what Rud Istvan was referencing:
“And on the shortest time frames, Lindzen observed about 2011 that the warming from ~1920-1945 is visually and statistically indistinguishable to that from ~1975-2000.”
James Hansen still publishes less than 0.2 deg C per decade for surface temperatures. It appears to me that the recent linear segment started about 1964. If you want to go back to 1880, the trend slope will be even lower.
https://www.columbia.edu/~mhs119/Temperature/
“comes from measured metrics.”
Does that change the fact that it’s a manipulative slogan? Why else would it be plastered at the top of the website?
“Does that change the fact that it’s a manipulative slogan?”
It is a measured fact. You are an example of the easily manipulated projecting.
No U.
Mr. Willard: Above, you aptly quote Tim’s bro, what was it again??
U are too dim to last very long here, what’s you’re next nom de plume?
You must be new here, Paul.
I’m not easily manipulated because I don’t believe anything I hear. I try to get as close to source data to fact check claims. Anthony’s viewership is a measured metric. Tamino’s emotional pleadings only work on the easily manipulated.
You sure are the master of and in your own mind, gyan!
Have you ever heard of self-hypnosis?
“It is a measured fact”
… strategically weaponized.
I understand that empirical facts are seen as weapons to those locked in ideological closed loops of perception. Normal people accept them as a basis for reality.
Correct. Thank you for volunteering as the example.
Phil Jones say there are three periods since the end of the Little Ice Age that warmed at the same magnitude. The period from 1850 to the 1880’s, and the period from the 1900’s to the 1930’s, and the period from the 1980’s to 1998, all warmed at the same magnitude,
There is no unprecedented warming today.
Not according to Andy May’s Figure 3 (“Reasonable Average”) from a separate blog post he links below:
What is unprecedented about the red star? It is exceeded in both the RWP and the Minoan in this reconstruction.
The plot above is from this post:
https://andymaypetrophysicist.com/2021/05/01/a-review-of-temperature-reconstructions/
It was about this time I stopped combining proxies.
I am using your figure because it contradicts claims by Tom Abbott and other commenters that the early 20th century was warmer than the present. The red star marking the present clearly exceeds the 1940 level.
Could be. The warming trend from 1910 to 1940 is very similar to the warming trend from 1980 to 2010 or so, but the latter period may be warmer. They are so close however, and the corrections applied to the various datasets are so large it is hard to be sure. I want to stay out of that fight. But I’m very sure the Roman Warm Period was as warm or warmer than today, the evidence is overwhelming in Europe, the Middle East, and in China.
Further the glacial data all over the world confirms it, Hannibal could not cross the Alps with elephants today.
“But I’m very sure the Roman Warm Period was as warm or warmer than today, the evidence is overwhelming in Europe, the Middle East, and in China.”
No, the planet is significantly warmer.
“Look at the spike at the end. The big, and most importantly the steep, scary spike at the end. That’s not an artifact of the way proxy ages were computed, or how the reconstruction was done, or the effect of proxy drop-out as records become more sparse in the later period. It’s what the thermometers say. Ignore them at your peril.
As scary as that is, what’s far more frightening is that it’s not going to stop.”
https://tamino.wordpress.com/2013/03/22/global-temperature-change-the-big-picture/
Your spike is less than 20 years which is the resolution of the proxies, you can’t possible say that, it is pure speculation. Wait until you have 40 years or 60 years of data, then you will know something.
Lecavalier et al. (2017) relies on ice-core records with far higher temporal resolution than mixed global proxy stacks, yet it still reproduces a hockey stick like warming.
This strongly indicates that the late Holocene warming signal is not contingent on proxy resolution limitations.
It is clear his model is flawed. Vinther shows the correct ice core record.
February 7, 2026 6:44 am
February 5, 2026 1:04 PM
“And their elevation corrections primarily affect early Holocene temperatures, not the modern blade…”
February 6, 2026 8:35 PM:
“The Innuitian elevation correction only materially affects the early Holocene. It has no almost bearing on the late Holocene portion of the Agassiz record.”
February 6, 2026 8:52 PM
“In the mid to late Holocene (the last 7–8 kyr) the reconstructions are nearly identical. That means the claim that modern temperatures are the warmest in the past 6,800–7,800 years is drawn from a part of the record where the two reconstructions agree, and is not undermined by the early Holocene adjustment…”
The entire difference between Vinther and Lecavalier is due to his Huy3 model, which is very suspect for the reasons I’ve already stated. If you believe his model, then you can accept his conclusions. I do not, so I don’t, at this point that is at the root of our disagreement. We cannot resolve it here.
“Huy3 model, which is very suspect for the reasons I’ve already stated. “
which is primarily an issue confined to the HCO.
The issue concerns the length of the HCO primarily. I don’t think the maximum temperature in the Arctic is very different, but Huy3 predicts that the HCO cools more quickly and earlier than historical events and glacial records indicate. The other good data show that the HCO extended to after 4,000 BP (after 2000BC).
Oh, good Lord! The Marcott spike (or Marcott tick”) has been thoroughly debunked, even by Marcott himself, who admitted it was due to one point in 1940 after all the other proxies had dropped out.
You can’t honestly believe that can you? Let me introduce you to the concept of proxy drop out and what it can do when you mix proxies with different temporal resolutions and differing end dates. See here for a discussion and references. I can’t believe you had the cojones to show that in a discussion with me of all people, hilarious.
https://andymaypetrophysicist.com/2017/05/31/a-holocene-temperature-reconstruction-part-1-the-antarctic/
Steve McIntyre @ur momisugly Climate Audit:
“The bias, introduced by ex post screening of a large network of proxies by correlation against increasing temperatures, has been noticed and commented on (more or less independently) by myself, David Stockwell, Jeff Id, Lucia and Lubos Motl. It is trivial to demonstrate through simulations, as each of us has done in our own slightly different ways.”
Apparently ex-post screening of samples is a common practice and a fundamental reasoning fallacy with proxy temperature reconstructions.
That’s the second time a link has gone haywire, sorry about that.
Either way your quote is appropriate, thanks. Bottom line, proxies are all over the place sometimes, so you can select a group of proxies to combine to form whatever reconstruction you want. Best to deal with the proxies one at a time and in light of historical records. Basically, all reconstructions, including my own, are crap.
Mickey’s hockey stick looks very different when you remove the CO2 constrained tree rings he chose.
And Briffa’s own tree ring data since 1900 looks very different from anything the climate hysterics want to see.
Yeah, Briffa figured out all the tree ring data was crap in the late 20th century a long time ago.
Certainly before then 1900’s they are highly dubious because there was a lower level of CO2, one of the things they absolutely MUST have for tree growth.
Mickey Mann’s graph could be better described as a CO2 graph.
And now more recent tree rings are more faithful, according to Mr. Nice.
That’s how we recognize Briffa scholars!
“Briffa’s own tree ring data”
There’s no such thing, and if you don’t know that, well, tough luck.
Willard,
Nonsense, Briffa’s reconstruction can be accessed here:
https://www.ncei.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/nhemtemp_data-noaa.txt
Briffa contributed data:
Pallasmaja (Finland), various North American sites (e.g., Mt. Angeles, Pike Peaks), and Russian sites.
For Yamal-related data (often linked to Briffa’s work): https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/noaa-tree-15339/html (ITRDB RUSS223, larch ring-width).
These are just examples. See his papers for further info.
First things first, Andy:
“Briffa et al, 1998″.
Then, second things second:
“Northern Hemisphere Temperature Reconstructions”
Summing up:
(1) not tree ring data, but reconstructions
(2) reconstructions-with-an-s
(3) only those of 1998
(4) not Briffa’s alone
(5) and the tree ring data are not his, which you now concede, albeit a tad too indirectly for an auditor.
Had you read the Auditor’s, you’d know it’s not Briffa’s series!
See the importance of citing one’s sources properly?
You do have a serious reading problem don’t you:
Briffa contributed data:
Pallasmaja (Finland), various North American sites (e.g., Mt. Angeles, Pike Peaks), and Russian sites.
That’s too bad, Andy. I suppose “Remember Yamal” won’t ring a bell to you. Perhaps you can answer this simple question: who sent the Auditor the data that the Auditor pretended for years not to have?
Also note that you said “Briffa’s data”. There’s shorthand, and then there’s creative license!
You really have a serious communication problem. Anyway, you seem stumped by academic citations, this article describing Briffa’s collective work might be more your speed:
https://en.wikipedia.org/wiki/Keith_Briffa
Note he collected tree ring data in Canada, Scandinavia, and Siberia among other sites. Obviously, he worked with a team and did not personally do all the work. The famous Yamal data is data he collected. All the data are available from NCEI and NOAA.
Playing dumb won’t work anymore, Andy.
Here are some breadcrumbs for you:
https://neverendingaudit.tumblr.com/tagged/RememberYamal
In one of these notes, you should be able to see who collected the Yamal series.
That web site is right up your alley!
What?
Ah, eff it, let’s go bowling.
Josh’s ‘Hockey Stick-O-Matic:
Mr. Hanley: Very good, but I would label the “waste” chute thus:
“non-conforming stuff that isn’t data after all, and cannot be shown to McIntyre or McKitrick or any other sob”
Maybe there’s a reason I’m not a cartoonist?
If you go back in history, using temperature proxies you will find there is a rise in temperature just before the sea level falls – just a blip for 1 to 2kyr. .
Snow is energy intensive. It takes around 1400kWh to get one tonne of water out of the ocean and deposit it on land. So NH oceans have to get a lot warmer yet before the snowfall overtakes the snow melt. I am still forecasting oceans starting their next fall in the J3000s. Permafrost could be advancing down slope and southward within 200 years. Greenland plateau already gaining altitude.
A lot more of the climate observations can be explained by looking at daily anomalies at sunlight across latitudes. For example, the north-south motion of the Sun relative to Earth has significant short term impact on solar intensity at the poles and elsewhere to a lesser degree. The Sun has strong northward trend since 1980. It will not move south of Earth’s elliptic again till 2037. There will be two temperature spikes in the 2030s.
Warming spike in the 1940s in Greenland totally NOT “unprecedented”.
Cooled since that 1940’s spike and is no warmer than that spike now.
Still well below MWP, RWP and Bronze age warm period
Here’s what happens when there’s no source and no cite:
https://www.theclimatebrink.com/p/climate-skeptics-have-new-favorite
Yet another idiotic paper comparing useless temperature and CO2 proxies for the whole Phanerozoic as if we knew how to date and age rocks accurately enough hundreds of millions of years ago. A quick review of the Holocene Temperature Conundrum shows how stupid that is:
https://andymaypetrophysicist.com/2023/02/24/the-holocene-temperature-conundrum/
“Yet another idiotic paper”
Insults.
“A quick review of the Holocene Temperature Conundrum shows how stupid that is”
Handwaving to more armwaving, grafted with more insults.
So Very Serious. Very much dignified.
As usual substance free insults. Compare the Holocene Temperature Conundrum to a Phanerozoic graph of a few CO2 and temperature proxies, what conclusions do you reach? For a little more context read this post:
https://andymaypetrophysicist.com/2021/08/18/the-paleocene-eocene-thermal-maximum-or-petm/
Using a Phanerozoic plot of CO2 and temperature proxies to show climate and temperature are somehow related is about as dumb as it gets, I’m afraid. They do it in AR6 also, see here:
https://andymaypetrophysicist.com/2023/02/04/the-ipcc-ar6-report-erases-the-holocene/
“As usual”
You can’t afford to make mistakes like that, Andy.
See here:
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4163137
Also here:
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4163110
Perhaps here too:
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4163129
Also search for “source:”. There are 8 so far. I can add a few dozens more, but Mr. Nice will have to ask nicely.
Let me offer you this very simple argument:
(A1) All reconstructions are wrong, including mine.
(A2) While it is remotely possible that current Arctic or global average temperature is higher than any seen in the past 6,800 years, it is very unlikely
You can’t claim both. So which one do you prefer?
You must be drunk commenting, that comment makes no sense at all. Explain when you sober up. I literally cannot make any sense of it all. You will need to explain what you mean.
Look, Andy.
You can’t reject reconstructions as bad in one comment, and then turn around and say that they’re good enough to make a likeliness claim.
If you say something about the very deep past, you need a reconstruction. If you reject reconstructions, then you can’t say anything about the very deep past. Including that anything is likely or unlikely.
There’s a difference between producing an estimate that rests on data and models, and expressing contrarian incredulity. Considering your meandering post, it’s unclear that you make the difference.
Is that clearer?
Not really, but I would like to drill down and see what you are saying, it still makes no sense to me.
Why is using a reconstruction to make a “remotely possible” likeliness claim inconsistent with reconstructions are wrong? I don’t think I used a reconstruction to make the claim at all, but even if I did it is not contradictory to do so. More explanation follows:
It really boils down to resolution as I’ve said many, many times. The more proxies, time, and area thrown into a reconstruction the worse it is for comparison to the present instrumental era. This is why I prefer to deal with one proxy at one location at a time.
I also prefer d18O ice core proxies because if the snow fall is rapid, they have high temporal resolution (~20 years to ~50 years) and they are reasonably accurate (+-0.3 deg. or so).
Many ocean and sediment proxies have even higher resolution, some are annual, and can be accurate.
Tree rings can be useful, but really only from around 1600AD to 1900AD, and even then, they are suspect since you can’t calibrate them with 20th century data.
Now the comment you claim is contradictory:
I did not make this judgement based on any reconstruction. I used individual proxies from several places. I cannot disprove that either the Arctic or global average temperature today is higher than any seen in the past 6,800 years because I don’t know of any accurate global or Arctic average temperature record back that far. But because all of the best located temperature proxies I have, that I think are accurate, show that today’s temperatures are lower than 6,800 years ago; I can say that it is likely today is colder than 6,800 years ago.
That should clearly explain the “apparent contradiction” you see. Read this carefully, you have a tendency to misread things.
“I did not make this judgement based on any reconstruction. I used individual proxies from several places.”
Is that a bit, Andy?
Unless and until these individual proxies from several places represent the area over which you are trying to opinionate, you have no business saying anything about that area.
Pray tell more about how you can read temperatures directly out of time series that are not temperatures, and why you assert that they are accurate.
No special pleading allowed, even for true Scotsmen!
“I did not make this judgement based on any reconstruction. I used individual proxies from several places. I cannot disprove that either the Arctic or global average temperature today is higher than any seen in the past 6,800 years because I don’t know of any accurate global or Arctic average temperature record back that far. But because all of the best located temperature proxies I have, that I think are accurate, show that today’s temperatures are lower than 6,800 years ago; I can say that it is likely today is colder than 6,800 years ago.”
In addition to what Willard just wrote, I’d like to emphasize again that you are privileging regions where strong regional masking is expected. Many proxies are dominated by local insolation, ocean circulation, or other regional factors that can obscure the response to radiative forcing.
If the goal is to assess the influence of greenhouse gases, the High Arctic is precisely where the signal should be strongest.
Global mean warming sets the baseline energy imbalance, and the Arctic responds more strongly through well understood amplification mechanisms.
That is also why Lecavalier’s result lends support to global Holocene reconstructions such as Kaufman and Marcott: the patterns are physically consistent with how excess radiative energy is partitioned and amplified within the climate system.
HadCrut2 for Greenland from 1870 ..
The shaded section is the little “up-tick”.. of the Mannian fabrications
It has cooled since that up-tick and in 2010 was still cooler than the peak
Try HadCrut3:
Source: https://cp.copernicus.org/articles/9/583/2013/cp-9-583-2013.pdf
After more adjustments you can have HadCrud 4 and 5 😉
I prefer more “original” data
Your preference for unsourced and fabricated graphs is duly noted, Mr. Nice:
https://crudata.uea.ac.uk/~timo/climgen/national/web/Greenland/obs.htm
Why did you pick December, because of Earth, Wind, and Fire?
Yeah, the original version is closer to reality than subsequent versions.
Look at the graph over Andy’s, Paul.
But let me help you first and point at the relevant bit.
Source: https://andymaypetrophysicist.com/2024/12/02/climate-change-over-the-past-4000-years/
The graph shown is inconsistent with both the official Greenland temperature record and Andy May’s Figure 3 (“Reasonable Average”) from a separate blog post he links below:
It is nice to see all the graphs in this thread. It tells me that there a number of independent researchers looking into weather and climate on this good earth, our home. I have not seen many graphs that completely destroy this information from the warmists that are usually here. When you have facts and data to support assertions, someone just saying “you are wrong” just doesn’t carry much weight.
Well said.
Balderdash.
Real data thugs cite their sources. They don’t misinterpret them. They don’t tweak their graphs. Also, they don’t gallop over cherries. They don’t confuse time scales or regions.
Mr. Nice has never played nice. It is a shame that you condone any of this, Andy.
Now all you have to do is cite factual rebuttal. 😉
You’re on.
Good enough for you?
Don’t forget outdated data archives (e.g., HadCRUT v2).
You mean one that was before the AGW scammer started adjusting everything ??
Good point!
That’s one reason I stick with the Hansen 1999 temperature chart. After that, Hansen, NASA and NOAA started bastardizing the temperature record big-time, to try to promote a CO2 Crisis, so 1999, is about as far as we get with accurate data. After that, the official temperature records are trash/Climate Alarmist propaganda, unfit for purpose.
When you have facts and data to support assertions, someone just saying “you are wrong” just doesn’t carry much weight.
Tell that to Mr. Nice, Jim:
[MR NICE] You mean one that was before the AGW scammer started adjusting everything ??
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4162817
Mr. Willard: So you identify as a “real data thug”, do you? First “real” thing you ever posted. CliSci is so well-staffed with data thugs, but you folks rarely admit it.
Better check in with your handlers on this.
No, Paul, I don’t. I identify as a ninja.
We definitely aren’t at the Auditor’s, where I started.
Mr. Willard: So ur handlers came up with ninja, even though you just described yourself above? Ur not very good at following ur own comment string, which I find so reassuring in a scientist.
Almost forgot- “ninja”???!! Hahaha (think Phyllis Diller).
Still here, Paul?
At least these readers are posting and examining observations and real data Willard, your problem is your comments are empty opinion and insults with no backup. Post some data, references, and analysis and we take you more seriously.
These “readers” actually don’t, dear Andy. They’re just posting and reposting the same memes all over again.
Your problem is that you’re stuck with Mr. Nice, who pretends to be a data thug whence he is one of the lousiest Climateball player one could find. And I’ve posted enough resources to show that your “empty” uppercut doesn’t land.
As for seriousness:
Sources:
https://andthentheresphysics.wordpress.com/2019/02/17/only-connect/#comment-143683
https://andthentheresphysics.wordpress.com/2019/02/17/only-connect/#comment-144298
Beware that in “data thug” there’s the word “thug”. If you act like one, I don’t mind responding in kind.
Many (not all) readers here do not post or engage with actual observations or real data objectively
Just look at the piece Paul Homewood published about a month ago:
https://wattsupwiththat.com/2026/01/02/met-office-blowing-hot-cold/
It’s obvious from years of reading his work that he has an agenda. The funny part is that he understands too little climate science to even be effective at deception.
“Just look at the piece Paul Homewood published about a month ago:
https://wattsupwiththat.com/2026/01/02/met-office-blowing-hot-cold/
It’s obvious from years of reading his work that he has an agenda. The funny part is that he understands too little climate science to even be effective at deception.”
Very true. I pounce on his bollocks, especially when he tries to rubbish the UKMO.
I am a retired meteorologist, having worked 32 years for them, and it is laughably easy to call him out.
Ah come on Eldrosion! Even you have to admit Paul Homewood’s post is funny.
I have no idea what that is all about. I have not been on Linkedin in years, so it cannot be recent. I was kicked out for being a climate heretic and never tried to go back. I cannot go back now, so your link is useless to me, and you have not identified the players, except for Javier, who actually does know about derivatives, as do I. You need to be less obscure to get more of a reply, sorry.
All your posts are very obscure and lack substance. As I said above, the lack of substance makes it very hard to take you seriously.
Mr. May: Yes, Willard’s every post, my sincere gratitude to you for deconstructing him so thoroughly.
“it cannot be recent”
Clicking on the links might help refresh your memory, Andy.
But if you only want a date, you can simply read them.
Feigning ignorance is not for you.
You have problems reading that is for sure. Like I said, I cannot log into Linkedin anymore, I was kicked out for being a climate heretic. Your link is useless to me. Anyway, it has been several years since I was on linkedin and I have no memory of what you quoted. Who was the colleague of mine that you refer to?
Yes, Andy. Everything goes so fast when we grow older.
Here is the link again:
https://andthentheresphysics.wordpress.com/2019/02/17/only-connect
Don’t click on the link for now! Just look at it. You should notice a date.
The post was written in 2019.
So yeah, it cannot be recent. So your “it cannot be recent” tells me that you haven’t paid much attention to what I wrote.
Now, clicking on the link above should lead you to a post. If you click on the links in it, you’ll see that it leads back here, at Tony’s. Then read the comments. You’ll see Nigel’s comments, at AT’s and at Tony’s.
For a guy who keeps posting links with no real explanation, you sure like to be taken by the hand!
OK, that link worked, then I did a search for my name and found it was a 2019 comment by Nigel Goodwin. I vaguely remember him, we worked together at SSI (Scientific Software-Intercomp) in the 1980s. He was quite young then, I think he may have just graduated. I quit SSI shortly after meeting him, the company then went bankrupt, and I don’t really know what happened to him after. As you say his comment was from 2019 and I have no recollection of a linkedin conversation with him before then, but I take him at his word, we must have had one.
What?? This makes no sense 2019 is not recent. And who knows how much longer before then the conversation he claims took place?
When have I ever posted a link with no explanation? Example please.
“When have I ever posted a link with no explanation?”
How many would you like until you concede that you’re a master handwaver, Andy?
I’ll only give you one of your most recent for free:
***
“that link worked, then I did a search for my name”
The first link worked too. And the second link too. And the third.
You just had to search of “Nigel”. The relevant part is “It led to me spending far too much of my time trying to explain derivatives, but Javier understand neither derivatives nor statistical significance.” And the relevant link is this one:
https://wattsupwiththat.com/2019/02/06/the-planet-is-no-longer-warming/#comment-2621983
Notice who edited that piece. No, not its author, that’s Javier. No, not the publisher either, that’s Anthony. I’m referring to the guy who has entered his friend Javier’s piece in WP.
You’ll never guess who that is!
Anywho. That was just in response to your silly jab about seriousness.
You should always be making plans for Nigel.
This is the full comment, how exactly is this posting a link with no explanation?
The rest of your comment is vacuous. Why would I care about Nigel? I haven’t spoken to him for 30 years. I wouldn’t know him if I saw him in the street. You seem obsessed with him for some reason. As for a seven-year-old post by Javier, who cares? Of course I edited it, I edited many posts for Javier back then. You’ve been drinking again.
You must be joking, Andy.
First of all, that full quote doesn’t explain anything. It’s throat clearing at its finest.
Second of all, nobody cares about your lack of care for Nigel. It’s utterly irrelevant to the point I was making, which is that you don’t have the formal chops to take yourself *that* seriously. Even if you did have the chops, you should not take yourself so seriously, for we only have one life.
Javier was wrong about a an elementary fact, you edited it, and you promoted it over an old, deprecated social. Par for your Climateball performance so far in this thread.
Did you at least get the “making plans for Nigel” reference?
OOOHH, Mr. thug, ur so menacing, save it for scary climate stories instead of puffing ur self-image.
Sorry, but it’s almost impossible to measure “air temperature”. At best, you are measuring the temperature of a thermometer in contact with air.
Not only that, but the temperature of the air tells you little about the temperature of the surface, or any heat sources keeping the “air” in gaseous form.
A rather pointless forum of measurebation, with the likelihood of a happy ending becoming more remote day by day.
Ice core proxies are proxies of air temperature, they are based on d18O.
https://pcc.uw.edu/wp-content/uploads/sites/15/2018/02/IceCore_Temp_UWinHS_12-14.pdf
“it is very unlikely”
Proving that assertion, instead of begging it, would have been great!
Mr. Willard: Didn’t read it, then?
Wanna bet, Paul?
Above, u quote Tim’s bro for the answer to ur “challenge”. U can still descend further into clownhood if u try.
However hard you try, Paul, you won’t be able to crowd out Mr. Nice’s cheerleading.
So what if it is warmer? Haven’t studies shown that human civilization flourished the most during warmer periods? Would we all be better off with the onset of another ice age? Regardless of what type of variation of weather or climate occurs, the alarmists will spring into action with their latest doomsday scenarios demanding the abandonment of fossil fuels so that renewables can rescue us from the apocalypse that keeps formulating only in their minds. So is it any wonder that climate action continues to rank at or near the bottom when national priorities are surveyed worldwide.
Kaufman, 2009 to my eye looks artificial/overprocessd.
Probably true.
Speculation without substance.
Andy, looking at the proxy data a thought comes to mind. Valid climate proxies should follow power-law distributions. If the data looks gaussian it has likely been incorrectly processed or is too short to deliver valid statistical results. This can be tested mathematically and could provide a standard test for climate proxies.
Maybe it should be, but is it? Proxies are modeled using linear fits to 20th century instrumental data. Thus, they assume linearity and a normal distribution. Sometimes this is true (d18O for example), but often it is not true as in tree rings and other biological proxies since they are affected by additional CO2 in addition to rising temperatures. Even d18O, one of the best proxies is questionable over time due to elevation changes.
One reason I like Rosenthal’s 500-m proxy in the Makassar Strait is it is deep, well located, and more unaffected by chaotic surface changes. Plus, it represents a large part of the North Pacific.
Our current beneficial, warm Holocene interglacial has been the enabler of mankind’s civilisation for the last 10,000 years. The congenial climate of the Holocene epoch spans from mankind’s earliest farming to the scientific and technological advances of the last 200 years.
However all the Northern Hemisphere Ice Core records from Greenland show:
When considering the scale of temperature changes that alarmists anticipate because of Man-made Global Warming and their view of the disastrous effects of additional Man-made Carbon Dioxide emissions in this century, it is useful to look at climate change from a longer term, century by century and even on a millennial perspective.
The much vaunted and much feared “fatal” tipping point of +2°C would only bring Global temperatures close to the level of the very congenial climate of “the Roman warm period”.
If it were possible to reach the “horrendous” level of +4°C postulated by Warmists, that extreme level of warming would still only bring temperatures to about the level of the previous Eemian maximum, a warm and abundant epoch, when hippopotami thrived in the Rhine delta.
storey tip
https://edmhdotme.wpcomstaging.com/the-holocene-context-for-man-made-global-warming/
Sorry to disappoint, but according to Andy May,
‘All reconstructions are wrong, including mine.’
Still true, but he is referring to a collection of proxies from Greenland ice cores. I like examining individual proxies from one location all together, see here:
https://andymaypetrophysicist.com/2021/05/01/a-review-of-temperature-reconstructions/
I came to my conclusion about reconstructions after years of examining individual proxies and hundreds of reconstructions.
From your blog post:
“. Most notably, Wyatt and Curry identified a low-frequency natural climate signal that they call a “stadium wave.” This model is based on a statistical analysis of observed events (especially the AMO) and not on the physical origins of these long-term climate cycles. But it does allow predictions to be made and the veracity and accuracy of the stadium wave hypothesis can and will be tested in the future”
We can already test the accuracy of the hypothesis based on the data we have collected since then.
From:
https://judithcurry.com/2013/10/10/the-stadium-wave/
“The stadium wave signal predicts that the current pause in global warming could extend into the 2030s,” Wyatt said, the paper’s lead author.
If the mid 2010s “pause” represented a transition into a colder cyclical period, extending the time window should reduce or reverse the warming trend.
Instead (using UAH) –
The warming rate from January 2014 to May 2021 (the month during which your blog post was published) is 0.20 °C/decade.
Extending the timeframe to January 2014 through December 2025, the warming rate increases to 0.36 °C/decade.
True, The stadium wave has not held up well recently.
“I like examining individual proxies from one location all together, see here:”
If individual proxies are the standard, then Lecavalier should be evaluated as one.
Again?? I must have written this response three times in this thread!
Lecavalier’s work with the individual ice core proxies is very valuable and helpful and I appreciate it. However, his Huy3 model is flawed and that invalidates his conclusions.
So, data analysis and concept -> good,
conclusions from his analysis -> wrong.
You don’t have to take my word for it, read Martin, et al., 2024, “Greenland Ice Cores Reveal a South‐To‐North Difference in Holocene Thermal Maximum Timings,” and Strunk, et al., 2018, “Relative Sea-Level Changes and Ice Sheet History in Finderup Land, North Greenland.”
February 5, 2026 1:04 PM
“And their elevation corrections primarily affect early Holocene temperatures, not the modern blade…”
February 6, 2026 8:35 PM:
“The Innuitian elevation correction only materially affects the early Holocene. It has no almost bearing on the late Holocene portion of the Agassiz record.”
I should be more precise and clarify that the elevation correction and Huy3 issues are manifestations of the same Holocene ice geometry problem (with meaningful consequences primarily during the early Holocene, when the Innuitian Ice Sheet still existed).
I suppose. The main problem is that his model pushes the end of the Holocene Climatic Optimum to an early date that is belied by nearly all the data I trust most, especially the historical data that says it was much later around or just before 1200BC (~3200 BP).
That claim is indefensible on physical grounds. At high northern latitudes, summer insolation peaked very early in the Holocene (roughly 11 – 9 kyr BP) due to orbital geometry. After that, it declines.
And another dataset you’ve said you trust (Vinther) actually converges with Lecavalier around ~8–7.5 kyr BP.
Sorry, 11-9kyr BP is too early, the peak temperatures were 8-6ky BP and Neoglacial cooling did not begin until after then when the Sahara turned into a desert. Further evidence is that the rate of sea level rise did not decrease to the present slow rate until after 7ky (maybe 6.6kyr) either.
See here:
https://andymaypetrophysicist.com/2015/11/26/climate-and-human-civilization-over-the-last-18000-years-updated/
Glacier evidence:
See Solomina, et al., 2015, Holocene glacier fluctuations. Especially note her compendium of global glacier advances and retreats in her figure 2. That cannot be reconciled with Huy3, especially not in Greenland.
Clearly the HCO did not end in Greenland, the Northern Hemisphere or globally until after 6ky BP.
For obvious reason glacier data trumps everything else, especially models.
My understanding is that the Holocene Optimum occurs in response to maximal summer solar insolation at 65 N latitude. Which is right smack in Greenland. Thus Greenland’s ice sheet retreats maximally somewhat after this time. And due to ice-albedo feedback, Arctic temperatures were expected to be, as we observe today, strongly amplified.
The rest of the world could not possibly have warmed as much as the Arctic or Greenland at the Holocene Optimum.
And other publications show that the Holocene Optimum globally “GMST was 0.7 °C (0.3, 1.8) warmer than the 19th Century”. I am skeptical of your one proxy in Indonesia as a good representative of the globe’s temperature.
Some misconceptions here. My one proxy in Indonesia is not meant to be a proxy for the globe, only the North Pacific sea surface temperature. Comparing historical events to a North Pacific proxy is not meant to imply it is a global proxy, it is just to show history and the proxy correspond, but they are separate things that reinforce one another. For more examples see Soon and Baliunas, 2003, doi: 10.3354/cr023089 and related papers. Also see the discussion here:
https://andymaypetrophysicist.com/2024/12/02/climate-change-over-the-past-4000-years/
The Holocene Optimum is related to insolation at 65 deg N latitude as shown clearly in figure 4 in the post.
You are correct, the rest of the world did not warm as much as the Arctic and Greenland.
“My one proxy in Indonesia is not meant to be a proxy for the globe, only the North Pacific sea surface temperature.”
Which is why you overlaid your graph with the remark that the series were 8,500 km away from one another. And also why you splice them on your overarching graph here:
https://andymaypetrophysicist.com/2024/12/02/climate-change-over-the-past-4000-years/
And it’s also why you speak of Climate Change over the past 4000 Years.
Either it’s just one proxy in Indonesia, one series in Greenland, and two pet reconstructions (not that they’re good, they’re all bad), or it’s something that is supposed to represent Climate Change over the past 4000 Years.
Which is it?
Wow! Perfect example of your serious reading comprehension problem. This is your question, I think.
The simple answer is both, but for a more nuanced and complete explanation read the first two paragraphs of the post you linked to below, after I repeat the link. And remember “climate change” does not equate to “global climate change.” Alarmists frequently use the phrase “climate change” very loosely, there should be an adjective in front of it.
https://andymaypetrophysicist.com/2024/12/02/climate-change-over-the-past-4000-years/
“I last wrote about Climate Change and Civilization for the past 4,000 Years in 2016. Since then, a lot has changed, and I’ve learned a lot more about the subject. First, we learned that various air and sea temperature proxies, such as ice core δ18O or tree rings, are all different. For a discussion of some temperature proxies used and the problems with them, see here. Proxies have different accuracies, they are often sensitive to the temperature of different seasons, and they have different temporal resolutions. Thus, as pointed out by Soon and Baliunas in 2003, they are all local and “cannot be combined into a hemispheric or global quantitative composite.”
The global average surface temperature (GAST) reconstruction relied upon in the IPCC AR6 report was by Kaufman, et al. The authors admit that the average spacing of each temperature (the temporal resolution) is 164 years. Thus, to compare the entire global instrumental temperature record to the proxies in a valid way, one must average all the daily readings since 1860 into one point. That is, the rate of warming since 1860 is irrelevant, the proxy record cannot see a 164-year increase. The problem of comparing daily modern instrumental temperature records to proxies is discussed by Renee Hannon here.”
That is sufficient to answer your question but read the rest for more context.
“The simple answer is both”
That won’t do, Andy. Temperature reconstructions are meant to reconstruct temperatures and represent climate change, whether they’re global or not.
Unless you think that Lecavalier & al did not reconstruct Greenland temperatures?
If you accept that proxies “cannot be combined into a hemispheric or global quantitative composite,” then you have no business saying anything about the likelihood of the global temperatures in past times. So here are a list of claims in your lead that you should delete:
“While it is remotely possible that current Arctic or global average temperature is higher than any seen in the past 6,800 years, it is very unlikely”
“It is almost certainly true that the rate of change in global or Arctic temperature observed recently is not unprecedented”
“This modern myth has been thoroughly debunked”
Thank you for bringing up Soon & Baliunas 2003. That shows the kind of argument you’re willing to pass as legitimate:
https://en.wikipedia.org/wiki/Soon_and_Baliunas_controversy
On this subject Wikipedia is a very unreliable source, note the infamous William Connolley was fired from Wikipedia for spreading nonsense on climate change. Here is a quick summary of the whole Willie Soon and Sallie Baliunas controversy:
The 2015 Attack
“… the height of the attacks on Willie Soon, by the New York Times (Gillis & Schwartz, 2015) was on February 21, 2015. They attacked Willie Soon personally. They relied upon false information from Kert Davies (Davies, 2020), the founder of the secretive Climate Investigations Center or CIC. Davies suggested that Willie Soon had a conflict of interest and lied in MSLB15 when he said he didn’t. Davies and the New York Times claimed that Soon had received undisclosed money from ExxonMobil and the Southern Company.
Most of the New York Times article is either wrong or misleading and in our new book, Politics and Climate Change: A History, we address each of their accusations. Here we will just cover a few of the most egregious lies. The basis for the attack was a Freedom of Information Act request (FOIA) to obtain internal documents from the Harvard-Smithsonian Center for Astrophysics, where Soon is employed as an astrophysicist. The FOIA was filed by Davies and Greenpeace.
More here:
https://andymaypetrophysicist.com/2020/11/14/the-paper-that-blew-it-up/
It is a very sad story, and it was the beginning of the end for the NY Times. They lost all credibility by getting in bed with Greenpeace.
You must be joking, Andy.
If your post is representative of your book, nobody should ever read it.
Representative – see what I did here?
Your intimation that you can represent climate change by directly accessing the inner depth of proxies without the need to reconstruct what you pontificate about provides an interesting variant of what I called for a long time the meteorological fallacy. In fact, after your persistent gaslighting, you leave me no other choice: time to write the post.
To give you an idea what it could look like:
https://andthentheresphysics.wordpress.com/2022/10/10/how-to-lord-comment-sections/
https://andthentheresphysics.wordpress.com/2024/01/16/how-to-cavil-like-cranks/
Say hi to Pat and to Our Lordship for me.
“In fact, after your persistent gaslighting, you leave me no other choice: time to write the post.”
Now that will be interesting. The main question is whether Andy will show up and defend himself. ATTP has a very technical audience, so he’ll be facing a challenge.
Mr. Willard: Which is it? Mr. May is here to edify; u are here to obscure. May is always clear and fully-disclosing his doubts about proxies, while working to extract useful information. U inflate ur ego by playing peanut gallery and doing nothing useful, trying to declare we must act based on proxies chosen by u. Ur long past ur use-by-date in these comments. Keep trying, I’m entertained by ur flopping like a fish outta water.
New phone. Who dis?
“U inflate ur ego”
What’s actually egotistical is dismissing an entire scientific field as a hoax while assuming one knows better. Of course, that characterization applies to many people here.
The only way to properly compare high-resolution instrumental data with lower-resolution proxy estimates is to use a box-filter, or convolution, to smooth the instrumental data to the best estimate for equivalent frequency response and probable effects of diffusion, sampling error, and less-than perfect correlation in the proxy parameter.
One way to accomplish that would be to trim the high-frequency components of a Fourier Transform (Convolution in the spatial domain is equivalent to multiplication in the frequency domain.) until the inverse-FT looks similar to the time-series proxy estimates. That can be fine-tuned by calculating the descriptive statistics to optimize the trimming results for regions of overlap. Instead of eliminating high-frequency components completely, one might consider adjusting the coefficients to weight the components differently, if one can make a case for the cause of the different effects related to the frequency.
One can expect that trimming the high-frequency components of the instrumental data will decrease the variance and range of the trimmed data to be a better comparison to the proxy data. Comparison of the adjusted (smoothed) instrumental data with the proxy data will give one a better idea of whether of not the claims being made are justified.
Interesting idea, but since the entire instrumental period is only 170 years and the normal (or average or median) temporal resolution of BEST’s proxies is 164 years (Kaufman, 2020, doi: 10.1038/s41597-020-0530-7) it is easier just to average the whole instrumental record to compare to reconstructions. Now some individual proxies (like those shown in figure 1) have 20-year resolution, so you can compare the modern era since 2000 to those by just averaging 20 or so years.
What I’m saying is we don’t really have enough data to make Fourier analysis work.
Andy, thanks for pointing out the resolution issues. When I wrote the comment I was looking at your Figure 1, assuming that the orange time-series was counting layers in the ice because it obviously has high-frequency components lacking in the black line.
I think that my suggestion is still valid for comparing time-series with different resolutions or sampling intervals. Anytime that one is dealing with time-series with different temporal resolutions, they should be low-pass filtered and/or resampled to match the lowest resolution data that are being compared. I don’t see that being done.
Good points, and yes it normally it is not done. Your technique would be good for the best proxies, those with high resolution.
The other problem that is more complicated is that most proxies are only sensitive to one season, often summer. And due to orbital precession and ocean cycles, changes in average temperature vary by season. But modern temperatures are typically averaged monthly and annually and cover the whole year, this makes instrumental records hard to compare to proxies longer-term. It is a very complex subject.
Sorry, this posted in the wrong place:
https://wattsupwiththat.com/2026/02/05/holocene-warming/#comment-4163948
Basically, the issue is this:
Fig. 4B shows the model failure is confined to the early Holocene.
But, if you don’t trust the model, then compare Lecavalier directly with Vinther (which is independent of the model) and note where the two reconstructions converge. Either way, the late-Holocene and modern parts of the record are unaffected.