By Andy May
Glacier length changes through time, they advance when the local climate around them is colder and retreat when it is warmer (Bray, 1968). Over century and greater time scales glacier length is considered a highly reliable indicator of both regional and worldwide warming trends according to Olga Solomina, Johannes Oerlemans, and the IPCC (Solomina et al., 2008), (Oerlemans, 2005) & (IPCC, 2001, pp. 127-130). While studying glacier lengths can illuminate long-term warming or cooling trends in glaciated areas is true, the idea that they can reveal hemisphere-wide or global climatic trends is somewhat speculative.
Advancing and retreating glaciers leave evidence of their fluctuations in length in glacial till deposits called moraines. Glacier moraines are easily identified and are distinct from other sediments and sedimentary rocks because they contain angular boulders, and they are unsorted and unstratified. Olga Solomina and colleagues in a 2015 review article, note:
“Studies of Holocene glacial geomorphic and sedimentological records provide the most direct means of determining the extent and timing of glacier oscillations. Until recently it has been difficult to define the ages of moraines in many regions because of the lack of appropriate dating techniques. Radiocarbon has been the most widely used and in some cases optically stimulated luminescence (OSL) dating has been implemented, but in most cases these can only be utilized to provide maximum and/or minimum ages on moraines by dating organic-rich deposits that are buried beneath moraines/tills, beyond the glacial limit (maximum ages), on top of moraines, or within the glacial limit (minimum ages). The development of terrestrial cosmogenic nuclide (TCN) dating, however, has provided a direct method of dating moraines and has led to a plethora of studies that are shedding new light on the nature of Holocene glacier fluctuations.” (Solomina et al., 2015)
Dating Glacial Advances
The TCN (terrestrial cosmogenic nuclide) dating technique (Larsen et al., 2021) is uniquely suited to dating the maximum extent of glacial advance, prior to a retreat. It is a geochronological method used to determine the exposure age of materials on Earth’s surface, such as rocks, sediments, or landforms. It works by measuring the concentration of rare isotopes (or more accurately nuclides, including isotopes of beryllium, chlorine and carbon) produced by interactions with cosmic rays. The nuclides accumulate over time and provide a “clock” for how long the material has been exposed to cosmic radiation. The technique is particularly valuable for dating Quaternary events from a few hundred years to several million years before present, depending on the nuclide and site conditions.
Target materials for TCN dating are large quartz rich boulders that have been ripped off bedrock by the glacier and lie exposed on a moraine crest. These would be very angular boulders that were not previously exposed until deposited in or on the glacial till. The TCN derived age identifies when the boulder was deposited and became stabilized on the top of the till. Factors that can interfere with accurate dating are significant erosion or long-term burial under ice and snow. Moraines are not a stable geological feature once deposited, especially if they are cored with ice. Boulders may shift with time and may contain nuclides from a previous exposure. Careful sampling and proper analysis of multiple boulders per site can usually detect, and sometimes correct, for these problems (Larsen et al., 2021).
Glacier advances and retreats are very long-term climate indicators. They are quite sensitive to small local changes in average temperature and can be dated accurately. They are most useful in detecting when a glacier changes from a long-term advance to a long-term retreat leaving a “terminal moraine.” A maximum retreat is harder to see, since subsequent advances often disrupt the terminal moraine of a retreat and boulders may contain nuclides accumulated during previous exposures (Larsen et al., 2021).
An Anthropogenic Warming Indicator?
Solomina, et al. believe that the current rate of glacier retreat is unusual and an indicator of anthropogenic warming. This is quite speculative due to the very short period of possible anthropogenic warming, roughly the past 70 years according to the IPCC (IPCC, 2021, p. 117). Since the world cooled from 1950 to ~1975, the period of warming is actually shorter, more like 50 years, and in the middle of this period, from 1998 to roughly 2013, there was another period of cooling (or at least a “pause” in warming) which casts further doubt on the hypothesis that humans have significantly affected climate with their greenhouse gas emissions. For a summary of a discussion of the so-called “hiatus in warming” by some prominent climate scientists see here.
Solomina et al. and the IPCC (IPCC, 2007b, p. 436) believe that the recent warming and the associated nearly global glacial retreat cannot be attributed to the same orbital causes as those present during the Holocene Climatic Optimum (or “HCO”, see here, figure 4), so they must be due to human greenhouse emissions. It is true that Earth’s orbital condition is different than during the HCO, but the choice of causes is not binary. The twentieth century contained the Modern Solar Maximum, the longest solar grand maximum in 2,000 (SN-S series) to 8,800 years (SN-L series) according to Usoskin et al. (Usoskin et al., 2007, Tables 2&3). Just because the orbital position has changed since the HCO does not mean that modern warming is due to human activities.
What is climate?
Climate is generally defined as the average or prevailing weather of an area over a long period of time, the minimum period to define climate is normally taken as 30 years, the “area” described by the term is undefined. Thus, to measure a change in climate one must have two non-overlapping periods of greater than 30 years each to compare. Even 30 years may be too short since the very influential AMO weather cycle is 60-70 years long. Other significant long-term weather oscillations are discussed here. Glacier length records are good long-term climate indicators if the length changes are a small fraction of the total average glacier length. Glacier length changes are useful on century to multi-century times scales (Oerlemans, 2012). There are some rare glacial records that are accurate at decadal time scales, but these are usually short records, span only the last one or two millennia, and are concentrated in the Alps and Scandinavia. In other cases, claims of decadal resolution are belied by neighboring inconsistent glacier decadal records (Oerlemans, 2012). Another complication is that glaciers are rarely in equilibrium with their environment and the response time to changes in local climate can be hundreds of years for larger glaciers on gentle slopes (IPCC, 2021, p. 1278) & (Oerlemans, 2005).
How large an area is needed to define a “climate.” This is a tough question, figure 1 suggests that climate changes are not uniform over the whole planet. The middle latitudes of the Northern Hemisphere (NH) march to their own drummer relative to the rest of the world and the same can be said of Antarctica and the Southern Hemispheric mid-latitudes (SH). I have often shown plots of the Rosenthal Makassar Strait and Vinther Greenland Holocene temperature reconstructions and believe that they represent climate changes in their immediate areas. But I doubt that plots of gridded or average hemisphere-wide or global temperature proxies mean very much, the term “climate” just isn’t well defined over such large areas.
Holocene Glacial Advances
Most glaciers have been retreating since the middle 19th century in the Northern Hemisphere and in some parts of the Southern Hemisphere but are still larger today than they were in the early and middle Holocene. Most glaciers reached their minimum Holocene extent between 8 kyrs and 6 kyrs (that is between 8,000 and 6,000 years ago). Subsequently glaciers expanded and reached their maximum Holocene extent between about 1500AD to 1850AD or so (IPCC, 2021, p. 345) & (Solomina et al., 2015). Importantly, most glaciers all over the world reached their maximum Holocene extent in the Little Ice Age, this includes all over the Northern and Southern Hemisphere and in the tropics. In figure 1 the maximum glacier advances peak between 1000AD and 2000AD for all regions. In Alaska, Greenland, Iceland, Scandinavia, Central Europe, Russia, the tropics, and Antarctica glaciers were smaller than today during the Roman Warm Period, roughly 250BC to 400AD (Solomina et al., 2015, Fig. 2).
Short-term and recent glacial retreats often yield poor results with wide age scatter, so accurately measuring retreat rates from the major Little Ice Age (LIA) glacier advances is problematic and limited to the instrumental era (Oerlemans, 2005) & (Oerlemans, 2012). Glacier retreats are rarely clean; they are characterized by frequent re-advances that contaminate young fresh boulders with disturbed boulders from earlier retreats or advances yielding a wide scatter of dates. Thus, we probably will not know how the current rate of glacial retreat compares to past retreats for several hundred years, if at all.
Comparing Glacier Advances and Retreats to other temperature records
The elements of global and Northern Hemispheric temperature changes during the Holocene are generally agreed by most scientists. There was a very rapid rise in temperature after the Younger Dryas cold period around 9,700BC at the beginning of the Holocene (Walker et al., 2009), the warming peaked during the Holocene Climatic Optimum (HCO) sometime before 3,500BC in the tropics and the Northern and Southern Hemisphere mid-latitudes (see here). It ended earlier in the Arctic and Antarctic, perhaps due to changes in obliquity that decreased insolation at the poles and increased it in the tropics (see here for a discussion).
After the end of the HCO, in the latitudes outside the polar regions around 4000BC, the Mid-Holocene Transition (MHT) period began. This was when the Sahara began to turn into a desert and temperatures declined (except in Antarctica) in a period called the Neoglacial into the Little Ice Age (LIA), the coldest period in the Holocene. Temperatures did not turn around and begin to warm until 1700 to 1850AD. The warming period after 1700AD is usually called the Modern Warm Period. The elements of the Holocene are identified in figure 1, the beginning and end of each period are approximate, since the transitions are gradual and do not occur synchronously across the globe.
Figure 1 plots latitude bounded temperature reconstructions using selected Holocene proxies from Marcott’s (Marcott et al., 2013) global collection. The details of how each reconstruction was made are explained in a series of posts here. I’m not fond of reconstructions like these because they can be misleading. The curves in figure 1 are probably directionally correct, but they are very low resolution and not very accurate, so the temperature anomalies must not be taken literally. They will not show climatic events that are shorter than about 150 years and the temperature accuracy is no better than ±0.5°C. Variability in temperature is higher than shown, thus these proxies cannot be compared to modern instrumental measured temperatures, although they often are, see here for more details.
As discussed in my last post and here it is better to discuss climate in a local context than regionally (as in figure 1) or globally. In the last post I plotted Vinther’s Greenland reconstruction and Rosenthal’s Makassar Strait reconstruction, each represents a relatively small area, is reasonably accurate, and each has a temporal resolution of between 20 and 50 years, much better than the average Holocene temperature proxy resolution of 164 years (Kaufman et al., 2020b). The best way to compare today to the past is within local climate regimes. However, to study global climate changes, one must make large area reconstructions like those plotted in figure 1 and remember that their temporal resolution and accuracy are poor.
As figure 1 makes clear, climate changes, at least as defined by average temperature, differ a lot by latitude. The middle northern latitudes (“NH”, 30N to 60N, black thick line in figure 1) stand out. NH, Antarctica, the Arctic, and the tropics warm faster in the early Holocene and the Southern Hemisphere (SH) warms later. Peak warming occurs late in the NH and SH and early in the Arctic and Antarctic. Temperatures drop early in the Antarctic and recover in the mid-Holocene Transition. During the Neoglacial period, prior to the Little Ice Age, most of the world oscillates around a fairly constant temperature or slightly declines as the NH temperature falls rapidly. After 1000AD temperatures fall in the Arctic, SH, and tropics, but rise in Antarctica. The tropics and the Arctic have two peak temperatures, one early in the Holocene and one during the mid-Holocene transition.
Glacial advances tell the same story. In figure 1, the three rows of numbers between -1.5 and -2 degrees are, top to bottom, the Northern Hemisphere, tropical, and Southern Hemisphere glacial advances as tabulated in Solomina, et al., 2015 in their table 2. I added the advances for each millennium. In Solomina et al.’s table 2 the values summed are the first values only, I ignored the possible duplicates that follow the plus signs.
Scanning the glacial advance totals, we can see that before 7,000BC they are more numerous. Between 7,000BC and 2,000BC there are fewer advances. After 2,000BC, as the Bronze Age collapses into the Greek Dark Age, the number of advances increases until it peaks after 1,000AD. By far, the Little Ice Age (LIA) sees the most glacial advances in the Holocene Epoch.
Discussion and Conclusions
The poor resolution and inaccurate (but directionally correct) latitude slice temperature reconstructions plotted in figure 1 are supported in a qualitative way by Solomina et al.’s glacial advance summary. The Holocene ITCZ shift that marks the beginning of the desertification of the Sahara falls at the second peak of the Antarctic, tropical, and Arctic records, as well as at the Southern Hemisphere peak Holocene temperature. Antarctica does not have a Little Ice Age anomaly, but all the other slices do, although they are not synchronous. The Northern Hemisphere Little Ice Age anomaly dwarfs those seen in the other slices. We read a lot about “Arctic amplification” but it is the Northern Hemisphere mid-latitude temperature record that stands out at this scale.
The Little Ice Age glacial advances from 1,000 to 2,000AD are the maximum seen in all three regions (NH, T, and SH) in the entire Holocene. Given the time frame of glacial advance and retreat moraine preservation and detection, glacial advances cannot be used to support or disprove anthropogenic warming for at least another one-hundred years and probably longer. Figure 1 also suggests that the idea of “global warming,” that is a uniform rise in temperature due to changes in greenhouse gases over the whole globe synchronously, is not supported over the Holocene. Figure 2 shows that “global warming” isn’t even a good description of what is happening today.
Figure 2 is from AR6 (IPCC, 2021, p. 316) and shows the warming globally from 1900-1980 (top map) and 1981-2020 (bottom map). Redish colors indicate warming and blue colors cooling. The x’s indicate grid cells with an insignificant trend. White areas are areas with insufficient data. The bottom line is that the aerial coverage, especially in the Southern Hemisphere is poor and that many areas have cooled over the past century, not warmed. It cannot be said that glacier fluctuations support the idea of recent anthropogenic warming, and there is considerable doubt in the instrumental data as well.
Works Cited
Bray, J. R. (1968). Glaciation and Solar Activity since the Fifth Century BC and the solar cycle. Nature, 220. Retrieved from https://www.nature.com/articles/220672a0
IPCC. (2001). Climate Change 2001: The Scientific Basis [TAR]. New York: University Press. Retrieved from https://www.ipcc.ch/site/assets/uploads/2018/03/WGI_TAR_full_report.pdf
IPCC. (2007b). WG1: Climate Change 2007: The Physical Science Basis (AR4). Cambridge University Press. Retrieved from https://www.ipcc.ch/site/assets/uploads/2018/05/ar4_wg1_full_report-1.pdf
IPCC. (2021). Climate Change 2021: The Physical Science Basis. In V. Masson-Delmotte, P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, . . . B. Zhou (Ed.)., WG1. Retrieved from https://www.ipcc.ch/report/ar6/wg1/
Kaufman, D., McKay, N., Routson, C., Erb, M., & Dätwyler, C. (2020b). A Global Database of Holocene Paleotemperature Records. Scientific Data, 7(201). https://doi.org/10.1038/s41597-020-0530-7
Larsen, N. K., Søndergaard, A. S., Levy, L. B., Laursen, C. H., Bjørk, A. A., Kjeldsen, K. K., . . . Kjær, K. H. (2021). Cosmogenic nuclide inheritance in Little Ice Age moraines – A case study from Greenland. Quaternary Geochronology, 65. https://doi.org/10.1016/j.quageo.2021.101200
Marcott, S. A., Shakun, J. D., Clark, P. U., & Mix, A. C. (2013, March 8). A Reconstruction of Regional and Global Temperature for the Past 11,300 Years. Science, 1198-1201. Retrieved from https://science.sciencemag.org/CONTENT/339/6124/1198.abstract
Oerlemans, J. (2005). Extracting a Climate Signal from 169 Glacier Records. Science, 308. https://doi.org/10.1126/science.1107046
Oerlemans, J. (2012). Linear Modelling Of Glacier Length Fluctuations. Geografiska Annaler: Series A, Physical Geography. https://doi.org/10.1111/j.1468-0459.2012.00469.x
Solomina, O. N., Bradley, R. S., Hodgson, D. A., Ivy-Ochs, S., Jomelli, V., Mackintosh, A. N., . . . Young, N. E. (2015). Holocene glacier fluctuations. Quaternary Science Reviews, 111. https://doi.org/10.1016/j.quascirev.2014.11.018
Solomina, O., Haeberli, W., Kull, C., & Wiles, G. (2008). Historical and Holocene glacier–climate variations: General concepts and overview. Global and Planetary Change, 60. https://doi.org/10.1016/j.gloplacha.2007.02.001
Tomkins, M. D., Dortch, J. M., Hughes, P. D., Huck, J. J., Pallàs, R., Rodés, Á., . . . Rodríguez-Rodríguez, L. (2021). Moraine crest or slope: An analysis of the effects of boulder position on cosmogenic exposure age. Earth and Planetary Science Letters, 570. https://doi.org/10.1016/j.epsl.2021.117092
Usoskin, I. G., Solanki, S. K., & Kovaltsov, G. A. (2007). Grand minima and maxima of solar activity: new observational constraints. Astronomy & Astrophysics, 471(1), 301-309. https://doi.org/10.1051/0004-6361:20077704
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
Fascinating post, Andy! The scientific evidence for CAGW seems to be retreating back into its burrow like Punxsutawney Phil. From there the Warmunists will forecast numerous tipping points only six generations hence, and call for strangling the baby before they throw out the bath water!
Climastrology, like every other form of Marxism, always seems to end up giving power to sociopaths, eventuating a fall from civil society into nihilism and despair! Only fools willingly vote for it.
Sorry, NYC!
The fanatics/extremist, just like sh.t, always flow to the top.
Figure 2 1981-2020 surface data compared with the measured lower troposphere same 40 year trend shows that, particularly in the Arctic and especially Greenland.
Thanks for the great map! I downloaded it and have attached it. There is some overall warming since 1978, but not much and it isn’t global.
“There is some overall warming since 1978, but not much and it isn’t global.”
Can you please tell me why you would have expected it to be global? (if you do)
It’s not me, the idea that it is global is from the alarmists or the “consensus.” Their hypothesis is that CO2 is a well-mixed gas that increases uniformly around the world, supposedly “trapping” heat so temperatures rise globally. This is as opposed to natural orbital forces which work by latitude. They ignore solar variability claiming it is insignificant. See here:
https://andymaypetrophysicist.com/2023/07/06/understanding-the-role-of-the-sun-in-climate-change/
They take this idea a little further by claiming that weather and weather cycles (think ENSO and AMO) just move heat about and don’t really change the global trend or energy balance. Thus, more heat is “trapped.”
A corollary of their idea is that as the world warms, the radiation out, versus radiation in (which is supposedly constant since the sun does not vary in their scheme) doesn’t change. But, of course as the world warms energy out is actually increasing, oops!
Their idea is laughably wrong, but it is what it is. My point is that since parts of the world are cooling, as the world overall is warming, the “CO2 did it all” hypothesis is incorrect and most of the causes of modern warming are natural. Additional CO2 probably has some effect, but we cannot measure it, probably because it is so small.
“ But, of course as the world warms energy out is actually increasing, oops!”
And the energy out goes up by T^x, where “x” would be “4” if the earth were a true black body, as opposed to temperature which goes up by T^1.
“Additional CO2 probably has some effect, but we cannot measure it, probably because it is so small.”
Since the measurement uncertainty of a “global temperature” is in at least the units digit, and more likely in the tens digit, there isn’t any way to actually know what the effect of CO2 really is.
If there were global warming due to additional CO2 and a successful model were constructed to explain natural climate change, and there were no unknown forces at work, then a CO2 effect could be computed. This is what the IPCC has been trying to do for over 30 years. But their models don’t work, so they cannot do the computation. Too bad.
Its been done. The IPCC alarmist group claim it must be manmade CO2 because models can’t match without it and we don’t know what else it can be. Its a Clouds and oceans model, but not a forecast model – simply one that can explain the past warming without engaging positive feedback loop implification mechanisms or high CO2 ECS factors. The author openly wants anyone to find errors/faults.
https://open.substack.com/pub/paulburgess3/p/explaining-every-temperature-change?utm_source=share&utm_medium=android&r=17bedn
If higher CO2 concentrations in the atmosphere make the planet greener, then that must have an impact on extreme ,up and down, temperatures . In Europe, we also see much more forest cover than 100 years ago, when it was still a vital resource.
Well, aside from a patch around Antarctica, that’s pretty much global. But I agree it’s very modest. Nothing worth destroying the economy over.
Much of the Southern Ocean and the South Pacific show no warming as well. Plus, the overall satellite measured LT temperature change is not very much. Nothing like the surface temperature graphs.
You do realise that the map shows the trend in degrees per decade and not the actual temperature change?
I do, most of the map is around .1 deg or so per decade or 1 deg per century. Not much. It’s a little higher in the Arctic, but they need it there.
True, all proxy reconstructions can so is that whatever the net anthropogenic temperature effect it is not historically abnormal let alone alarming.
From the article: “Since the world cooled from 1950 to ~1975, the period of warming is actually shorter, more like 50 years, and in the middle of this period, from 1998 to roughly 2013, there was another period of cooling (or at least a “pause” in warming) which casts further doubt on the hypothesis that humans have significantly affected climate with their greenhouse gas emissions.”
Well, NASA and NOAA didn’t like the fact that cooling set in after 1998, because that would not look good for people claiming more CO2 means more heat, so to preserve their “hotter and hotter and hotter” Climate Alarm Narrative, they both bastardized the temperature records, and during this period of cooling, NASA and NOAA declared that 10 years of the period from 1998 to 2015 were unprecedentedly hot, claiming 10 of these years were hotter than 1998, and even going so far as to make subsequent years hotter than the previous year (by one one-thousandths of a degree) to enable them to declare each year was the “hottest year evah!”
NASA Climate and NOAA are a bunch of liars who should be investigated for scientific fraud. These people are activists not scientists.
That figure 1 may tell us a lot. For a start the Little Ice Age stands out. I wonder if future researchers would view it as similar to a Dryas Event. Also it is quite obvious that the descent into the next glaciation began some 7000 years ago and that the Northern Hemisphere has been cooling steadily at 0.5C per thousand years.
We know the LIA was a seriously tough time with widespread famine due to crop failures. So a temperature at minus 2.5 is bad news. Perhaps atmosphere fertilising with CO2 will help a bit but I think we can expect serious trouble at -2C. Extrapolating the decreasing temperature profile from -5000 to +1000 tells me that will happen in 500 to 700 years. The next glaciation may be nearer than we think.
“Northern Hemisphere has been cooling steadily at 0.5C per thousand years.”
And it is currently warming at a rate of 0.14 degrees per decade. Which is roughly
100 times faster than the previous decline but apparently that is nothing unprecedented.
GISP shows many periods of warming and cooling that are at least as fast, and much more protracted than the tiny warming since 1900
Yep, and this modern warming is likely only temporary based on solar data with the coming solar minima in SC26-27 cooling can be expected to continue over the next two years.
Note how the goalposts are being moved: the danger is no longer the warming, but instead the rate of change. Climatistas are real weasels.
Great essay posted by Andy. I would add that the “health” of a glacier is also affected by the amount of snow accumulation in the uptake zone.
That is true and I thought about bringing in the precipitation part, but that requires a lot of explanation, and the post was already getting too long. Summer temperatures are important and so is the amount of rainfall in glacier retreats. In the Himalayas increases in rainfall have been linked to ice losses. Winter snowfall is very important in glacier growth. In the Patagonia, increased snowfall is helping to attenuate glacier retreat. Low snowfall in dry areas of Antarctica slow growth, even though temperatures are very low. Recently there has been more rain and less snow in glaciated areas, causing more rapid retreats.
In Karakoram and in nearby areas, north of Pakistan, snowfall has increased, causing rapid glacier growth. One of the few places where glaciers are growing. The east Antarctica ice sheet is growing, although slowly. There is also growth in Recherchebreen in the Arctic, north of Norway.
Another interesting phenomenon is the post glacial high stand around 6000 BC, clearly visible in the young coastal plain (jonge kustvlakte) in Suriname
And recall, researchers have found that the current level of solar activity is the highest in thousands of years.
https://www.mpg.de/research/sun-activity-high
True, from the post:
The three strong glacier advance periods between 3000 and 500 AD in Fig 1 are interesting, none of them were during the grand solar minima episodes. From 2225 BC and from 2000 BC were a pair of longer duration grand solar minima, and another pair back to back from 1364 BC and from 1250 BC. Otherwise known as the 4.2kyr and 3.2kyr aridity events. The Early Antique Little Ice grand solar minimum from 350 AD also shows retreat rather than advance.
I assume you mean 3,000BC
The attached graph has Usoskin’s solar grand minima (SGM) plotted after 2,000BC. There are several in your period, including one just before the end of the Bronze Age when many glaciers advanced, for example the Aletsch Glacier and other European alpine glaciers.
Not shown in the plot is an SGM centered on 2,860BC, which quickly followed one at 3,335BC, both were very significant. These occur right at the beginning of the Neoglacial Period, and the latter is part of a 3 SGM cluster from 3,625 to 3,335BC.
Ah my bad, I was looking at the blue line which is Antarctic temperatures.
With my planetary correlations I have plotted the start date and duration of each centennial solar minimum from 4700 BC, which is as far as my astronomy program goes back. The shortest centennial minima are 2 solar cycles long, and the longest are 5 solar cycles long. For the periods you have noted, these are my start dates and lengths:
from
3615 BC, 2 cycles
3505 BC, 3 cycles
3390 BC, 2 cycles
3295 BC, 3 cycles
3195 BC, 3 cycles
3085 BC, 4 cycles
2960 BC, 3 cycles
2860 BC, 4 cycles.
For comparison, the Maunder Minimum plots out at being 3 cycles long, from the late 1660’s to around 1705, which is when the cold weather actually happened. Most of the 1650’s to mid 1660’s were warm to hot in western Europe. The Sporer Minimum plots out as being 5 cycles long, from around 1425 and ending in the 1480’s. There is also an unknown centennial minimum from 1550. Most of the longer GSM are 4 cycles long, there are very few at 5, a notable example is 1250-1195 BC of the Late Bronze Age collapse.
Sorry there is a typo there, Maunder was 4 solar cycles long.
I had a comment here?
There is nothing in pending and nothing in spam with your name. I don’t know what happened to it.
Hi Andy. I just wanted to say thank you for your report! And if you would mind if I make a shortened version for our South African and Dutch websites. As it happened, I also recently made a shortened version of the report by Bourgois 2024 and how the story of the sword of Damocles that was used by him in the title fits in. Read the post script.
https://www.climategate.nl/2026/02/het-zwaard-van-damocles-achter-het-gordijn-van-de-opwarming-van-de-aarde-een-overzicht/
It is in Dutch but you can use the translate button in the left hand corner.
Fine with me, please go ahead.
Great post—clear, evidence-based, and well-argued. You effectively highlight how Holocene glacier advances peaked during the Little Ice Age across hemispheres and tropics, supported by Solomina et al.’s data. The discussion on TCN dating limitations, glacier response times, and the challenges in using recent retreats as an anthropogenic signal is spot-on. I have a couple glacial erratics in the river at my Alaska home, I would love to date.
Nice job tying in the Modern Solar Maximum and questioning uniform “global” warming. This heterogeneity is why “global warming” metrics (like the ~1.1–1.2°C rise since pre-industrial) mask big local meaningful variations.
Seems that modern warming shows less effect on glaciers than in the past. For example: Alpine glacier record during the Holocene:
Part of the problem is the response time as I say in the post, it can be hundreds of years. The glacier signal may not appear for a while.
climate is normally taken as 30 years, the “area” described by the term is undefined. Thus, to measure a change in climate one must have two non-overlapping periods of greater than 30 years
Why don’t we breakdown all the areas of the world in to something like 5 main zones and further subdivide these into a total of 30 to 35 Subsections. Then on a map, interpolate onto a 0.5° longitude × 0.5° latitude grid.
Then after 25 or 30 years see where this ‘Climate Change’ is happening and how bad it is. We base the changes as ‘GOOD’ for areas that have More Life and ‘BAD’ for for areas that have Less Life. Let’s Call it a Köppen Classification Map, because that is just what Wladimir Köppen did starting in 1884.
Here
In graph form for the changes. A & C have more life, i.e. Good – B Dry (includes cold dry) is still better than D (Snow) and E (Polar) i.e. Bad.
So Good Areas, less than 1/2 percent and Very Bad Polar down 3.5% vs Just Bad Dry up 3% & Snow down 1.5%. Don’t see much Catastrophic going on.
The Köppen Classification System is invaluable; it is basically how Chris Scotese gets his equator to pole gradients. Thanks for the great comment. If one were to define areas in climate, it is the place to start. Scotese has a good discussion of them here:
https://www.sciencedirect.com/science/article/abs/pii/S0012825221000027
This is also where I got the idea to make the latitude slices I use in figure 1.
DD More, there was an important study using the Köppen categories to evaluate how climates (plural) have changed in recent history. The paper is Chen, D. and H. W. Chen, 2013: Using the Köppen classification to quantify climate variation and change: An example for 1901–2010. Available at their website here:
https://hanschen.org/koppen/#home
My synopsis is :
https://rclutz.com/2016/05/17/data-vs-models-4-climates-changing/
This map alone punctures the entire CAGW narrative definitively. It should be more widely known.