Geophysical consequences of celestial mechanics

by Vincent Courtillot, Jean-Louis Le Mouel and Fernando Lopes

Sources of variability of some terrestrial and solar phenomena.

As former members of the geomagnetism department at IPGP (Institut de Physique du Globe de Paris), we have always retained an interest in solar-terrestrial relationships. Being in charge of geophysical observatories, we have always paid the foremost attention to long series of observations and as a consequence to methods of time series analysis. As of some five years ago, we have undertaken a systematic study of several long series of observations recorded around the globe (“long” means from several decades up to three centuries).

The research program has been quite productive, with the publication of some 24 articles in the past five years (all freely available online; references at the end of this note). The papers have been published in a very diverse set of journals, mostly in geophysics and astrophysics (in a broad sense). Because we came from the solid Earth geophysics community, it was not always easy at first to be recognized. Thus, we published in those journals where our French IPCC colleagues published, such as Cryosphere or Earth and Planetary Science Letters, MDPI or Frontiers. As a result, readers may have found it uneasy to grasp the wider picture. This short note is intended to try and draw this wider picture, to stress some of its consequences in the spirit of the paper’s title, and to give full references to the papers published in the frame of the program.

We have first determined the spectral content of many long series of observations, using either the Wavelet Method (WM) or Singular Spectrum Analysis (SSA). These series include global mean temperature and pressure of the lower atmosphere, a number of climate-related indices, solar activity through sunspots, length of the day, geomagnetic indices, extent of high latitude sea-ice, and more…
SSA allows one to decompose (in a way that a posteriori makes sense) a time series into a smooth trend and a series of components characterized by specific periodicities or pseudo-periods, based on which the series can be filtered and reconstructed.

We first applied the method to the series of sunspot numbers. The series could be satisfactorily reconstructed from simply a (rather flat) trend and two components with periods 11 years (Schwabe cycle) and 90 years (Gleissberg cycle). More interestingly, these components allow one to construct a precise and robust model of solar activity and to predict (so far rather accurately) the ongoing sunspot cycle and beyond [ref 1, 2, 3].

We have next determined the SSA components of the length of day (or Earth’s rotation velocity) and motions of our planet’s pole of rotation. To the Schwabe and Gleissberg cycles could thus be added the Hale (~22 years) and Jose (~160 years) cycles [ref 4, 5, 6]. We also analyzed tide gauges and sea-level change [ref 7, 8]. In all these series we could recognize the signatures of the four Jovian planets (Jupiter, Saturn, Uranus and Neptune): i.e. their periods of rotation and many of their “commensurable” periods. This argues for a mechanism involving exchanges of angular momentum between the Sun, Earth and planets. Variations in the inclination of the rotation axis due to this coupling in turn affect insolation, much in the way exemplified by Milankovic cycles at much longer periods (from tens of thousands to millions of years). We propose to extend the concept of Milankovic cycles to the much shorter periods we have analyzed [ref 9, 10].

The main components mentioned above are common (in whole or in part) to all the series we have analyzed [ref 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]. The fact that these series of components are found in the rotational mechanics of the planets and in many Earth-bound phenomena argues for a causal (forcing) relationship that can only work one way. The components one finds in sea level, pressure, temperature… must arise from a causal chain going (1) from Jovian planets to the Sun
(or directly to Earth), then (2) to inclination changes in Earth’s rotation axis, with (3) consequences on insolation changes (therefore climate), sea level and tides [ref 8, 10, 17].

We note that trends could actually correspond to still other pseudo-periodic components with much longer pseudo-periods (longer than the data interval). As a result, we argue that a very large part of the geophysical and atmospheric variations covered by the series we have analyzed appear to have an external origin (astronomical or gravitational). The perturbing effects of the giant planets correspond to a remarkable set of frequencies [ref 5, 19] that modulate (force) solar activity, variations in inclination of the Earth’s rotation, many terrestrial parameters among which sea level, oceanographic indices, sea – ice and finally temperature. These components have in general not yet been modeled.These works shed light and are in turn illuminated by the works of giants, the Legendre, Laplace, Lagrange and Poisson, who revolutionized geophysics [ref 25, 26, 27, 28]. The core of their elegant physics explains well the careful observations gathered in the past 200 years.

The first results of our research program have been discussed in an informal seminar at the Paris Academy of Sciences last May. Some 20 academy members attended and a lively open discussion followed. We hope this open, truly scientific attitude prevails.

About the authors. Vincent Courtillot ( and Jean-Louis Le Mouël are both emeriti professors of Geophysics at University of Paris, members of the Paris Academy of Sciences and former directors of Institut de Physique du Globe de Paris. Fernand Lopes (, also formerly at IPGP, now at Museum National d’Histoire Naturelle, is a Research Engineer with a PhD in geophysics and a specialty in computing, inverse problems and time series analysis.

JC note:  This is an important body of work, addressing many “known unknowns” in the climate system.  I encourage you to pick a paper, read it, and comment on it.

Papers published in the frame of this research :
• [ref 1] Le Mouël, J. L., Lopes, F., Courtillot, V. (2017). Identification of Gleissberg cycles and a rising trend in a 315-year-long series of sunspot numbers. Solar Physics, 292(3), 43.
• [ref 2] Le Mouël, J. L., Lopes, F., Courtillot, V. (2020). Solar turbulence from sunspot records. Monthly Notices of the Royal Astronomical Society, 492(1), 1416-1420.
• [ref 3] Courtillot, V., Lopes, F., Le Mouël, J. L. (2021). On the prediction of solar cycles. Solar Physics, 296, 1-23.
• [ref 4] Le Mouël, J. L., Lopes, F., Courtillot, V., Gibert, D. (2019). On forcings of length of day changes: From 9-day to 18.6-year oscillations. Physics of the Earth and Planetary Interiors, 292, 1-11.
• [ref 5] Lopes, F., Le Mouël, J. L., Courtillot, V., Gibert, D. (2021). On the shoulders of Laplace. Physics of the Earth and Planetary Interiors, 316, 106693.
• [ref 6] Lopes, F., Courtillot, V., Gibert, D., Mouël, J. L. L. (2022). On two formulations of polar motion and identification of its sources. Geosciences, 12(11), 398.
• [ref 7] Le Mouël, J. L., Lopes, F., Courtillot, V. (2021). Sea-Level Change at the Brest (France) Tide Gauge and the Markowitz Component of Earth’s Rotation. Journal of Coastal Research, 37(4), 683-690.
• [ref 8] Courtillot, V., Le Mouël, J. L., Lopes, F., Gibert, D. (2022). On sea-level change in coastal areas. Journal of Marine Science and Engineering, 10(12), 1871.
• [ref 9] Lopes, F., Courtillot, V., Gibert, D., Le Mouël, J. L. (2022). Extending the range of milankovic cycles and resulting global temperature variations to shorter periods (1–100 year range). Geosciences, 12(12), 448.

• [ref 10] Courtillot, V., Lopes, F., Gibert, D., Boulé, J. B., Le Mouël, J. L. (2023). On variations of global mean surface temperature: When Laplace meets Milankovi\’c. arXiv preprint arXiv:2306.03442. (in sub)
• [ref 11] Courtillot, V., Le Mouël, J. L., Kossobokov, V., Gibert, D., Lopes, F. (2013). Multi- decadal trends of global surface temperature: A broken line with alternating~ 30 yr linear segments?. Atmospheric and Climate Sciences, 3, 364-371.

• [ref 12] Le Mouël, J. L., Lopes, F., Courtillot, V. (2019). A solar signature in many climate indices. Journal of Geophysical Research: Atmospheres, 124(5), 2600-2619.
• [ref 13] Le Mouël, J. L., Lopes, F., Courtillot, V. (2019). Singular spectral analysis of the aa and Dst geomagnetic indices. Journal of Geophysical Research: Space Physics, 124(8), 6403-6417.
• [ref 14] Le Mouël, J. L., Lopes, F., & Courtillot, V. (2020). Characteristic time scales of decadal to centennial changes in global surface temperatures over the past 150 years. Earth and Space Science, 7(4), e2019EA000671.
• [ref 15] Dumont, S., Le Mouël, J. L., Courtillot, V., Lopes, F., Sigmundsson, F., Coppola, D., … Bean, C. J. (2020). The dynamics of a long-lasting effusive eruption modulated by Earth tides. Earth and Planetary Science Letters, 536, 116145.
• [ref 16] Le Mouël, J. L., Lopes, F., Courtillot, V. (2021). A strong link between variations in sea-ice extent and global atmospheric pressure?. The Cryosphere Discussions, 1-28.
• [ref 17] Lopes, F., Zuddas, P., Courtillot, V., Le Mouël, J. L., Boulé, J. B., Maineult, A., Gèze, M. (2021). Milankovic Pseudo-cycles Recorded in Sediments and Ice Cores Extracted by Singular Spectrum Analysis. Climate of the Past Discussions, 1-17.
• [ref 18] Lopes, F., Courtillot, V., & Le Mouël, J. L. (2022). Triskeles and Symmetries of Mean Global Sea-Level Pressure. Atmosphere, 13(9), 1354.
• [ref 19] Lopes, F., Courtillot, V., Gibert, D., Le Mouël, J. L., Boulé, J.B (2022). On pseudo- periodic perturbations of planetary orbits, and oscillations of Earth’s rotation and revolution: Lagrange’s formulation. arXiv preprint arXiv:2209.07213.
• [ref 20] Courtillot, V., Le Mouël, J. L., Lopes, F., Gibert, D. (2022). On the nature and origin of atmospheric annual and semi-annual oscillations. Atmosphere, 13(11), 1907.
• [ref 21] Lopes, F., Courtillot, V., Gibert, D., Mouël, J. L. L. (2023). On the annual and semi-annual components of variations in extent of Arctic and Antarctic sea-ice. Geosciences, 13(1), 21.
• [ref 22] Le Mouël, J. L., Gibert, D., Courtillot, V., Dumont, S., Ars, J., Petrosino, S., … Geze, M. (2023). On the external forcing of global eruptive activity in the past 300 years. arXiv preprint arXiv:2304.09564. (just accepted in Frontiers in Geosciences)
• [ref 23] Courtillot, V., Boulé, J. B., Le Mouël, J. L., Gibert, D., Zuddas, P., Maineult, A., … & Lopes, F. (2023). A living forest of Tibetan Juniper trees as a new kind of astronomical and geophysical observatory. arXiv e-prints, arXiv-2306. (in sub)
• [ref 24] Le Mouël, J. L., Lopes, F., Courtillot, V., Gibert, D., & Boulé, J. B. (2023). Is the earth’s magnetic field a constant? a legacy of Poisson. Geosciences, 13(7), 202.

104 responses to “Geophysical consequences of celestial mechanics

  1. Refreshing. Encouraging focus on stuff not “understood”.

    • Joe - the non climate scientist

      Yes very interesting to learn / acknowledge the unknowns. I am currently reading book on the WWII pacific island campaigns and inability to correctly predict the tides due to gravitational factors of the moon, sun and other planets. While not directly on point with the post, it does touch on the extreme amount of unknown factors.

  2. Nature has cycles on decadal, centennial and millennial time scales. Add to that the role of the moon and big planets, Jupiter and Saturn, and the effects on the geomagnetic field and galactic cosmic radiation and little is needed — indeed little room is left — for postulating a human causation as an additional factor let alone a rational explanation for all or even most of observed climate change.

  3. ref 3. On the prediction of solar cycles.

    Firstly, the Gleissberg cycle is variable from 80 to 130 years, and is another name for the cycle of centennial solar minima.
    This cycle is a product of the integrated synodic cycles of Venus, Earth, Jupiter, and Uranus, at 110.5 years, and the length of the centennial minima vary over a 863 year cycle. Sunspot cycle maximums occur at syzygies and quadratures within elliptical orbit paths, if the orbits were circular there would far less variation in the Gleissberg cycle length.

    The timing of each sunspot cycle maximum through the centennial cycle, is initially when Earth-Venus inferior conjunctions are in closer alignment with Uranus. Even numbered cycles have Jupiter near inferior or near superior conjunction with Uranus, and odd numbered cycles have Jupiter near either quadrature with Uranus. With a solar cycle length of three quarters of a Jupiter-Uranus synodic period, at ~10.4 years, and a typical rise time from minimum to maximum of one quarter of a Jupiter-Uranus synodic period, at ~3.5 years.

    After 5-8 and occasionally 10 sunspot cycles, the Earth-Venus inferior conjunctions begin to reach in line with Uranus far before Jupiter can reach a syzygy or quadrature with Uranus, at which point Earth, Venus, and Jupiter next perform similar quadrupole alignments with Neptune at each sunspot cycle maximum for 2-5 cycles as a surrogate for Uranus, until they can physically regain quadrupole alignments with Uranus again. This typically leads to longer sunspot cycles leading into and out of each centennial solar minimum, but with the very shortest cycles occurring in the middle of longer centennial solar minima, as the Earth-Venus-Jupiter quadrupole alignments return faster to Neptune than to Uranus as its orbit is slower. The Neptune based cycles define each centennial solar minimum, and reveal an additional and as yet unnamed centennial solar minimum from 1550, between the Sporer and Maunder minimums.

    The Lyons Cycle:

    • I would like people to study these correlations with each solar cycle maximum. The tool required is an astronomy program with a heliocentric mode, such as TheSky or Alcyone. Start at 8th May 1606, and step ahead in intervals of 291.96096 days, noting when the inferior conjunctions of Earth and Venus are in closer alignment with Uranus, and noting the position of Jupiter in relation to Uranus. Which gives 1606, 1617, 1627, 1638, 1647 (Dec), 1659. The next E-V conjunction closer in line with Uranus fails to produce a cycle maximum as Jupiter is now lagging around 2 years behind reaching a quadrature with Uranus. This cycle has its maximum in (4th Feb) 1675, with the E-V inferior conjunction now opposite Neptune, and with Jupiter square to Neptune. This is the first true centennial minimum cycle of the Maunder Minimum, and it is when the negative NAO regime and cold weather in Europe began. The 1650’s to mid 1660’s were mostly very warm to hot in Europe. The following two cycle maximums have the E-V inferior conjunction in line with Neptune again, in (Sept) 1684 and (June) 1693, agreeing with the sunspot cycle record.
      The first cycle to mark the end of Maunder had its maximum in (26th Jan) 1707 (+/- 1yr), with the E-V inferior conjunction back in line with Uranus again, until Dalton.
      The current centennial minimum is over after solar cycle 25, but the following one from the 2090’s maps out as being majorly long, and going by the 863 year cycle, it should be the start of the next grand solar minimum series.

  4. ref 9.
    That’s the AMO, every other warm phase is during a centennial solar minimum, so its long term mean frequency must be 54 years. The last two AMO envelopes at 60 and then 70 years is because the previous centennial solar minimum began 130 years before the present one began. The colder AMO anomalies correlate with a longer day length, stronger solar wind states, and positive Northern Annular Mode regimes.

  5. ref 11.
    Multi-Decadal Trends of Global Surface Temperature: A Broken Line with Alternating ~30 yr Linear Segments?

    The AMO had warming phases from 1925 and from 1995, that’s 70 years, and the cold phases are shorter than the warm phases. I would expect a cold blob around solar cycle 25 maximum like in 2013-15, but I don’t expect a 1965 style proper cooling until the 2030’s.

  6. ref 12.
    The solar wind does not follow sunspot cycles, there were major lows at cycle maximums in 1969 and 1979-80, then from the 1990’s the major lows shifted to just past cycle minimum.

    UK temperatures versus solar cycles, note phase shifts:

    And the reverse with the AMO, it is colder when the solar wind is stronger, in the mid 1970’s, mid 1980’s, and early 1990’s.

  7. ‘Winter weather is making a comeback. After a warm winter anomaly last year, traditional cool temperatures and snowy weather conditions will return to the contiguous United States.’ ~Farmer’s Almanac, Winter 2024

  8. This is all about a static climate responses to external factors.
    The climate has a lot of water that changes state, the climate has internal responses that sometimes resonate in phase with some external factors and sometimes does not resonate in phase with external factors.
    No one is actually studying the internal natural responses.
    Ice ages are times with much ice spread on a lot of land.
    Warm times are times when the ice is not spread on a lot of land.
    Sometimes the changes from warm to cold or cold to warm do fall in phase with a change in the external forcing, but many similar changes in the external forcing do not correlate with internal change.

    • Ireneusz Palmowski

      Over the next decades, warm oceans in the northern hemisphere will increase winter snowfall. This will allow ice to accumulate in Greenland and gradually.

  9. Ireneusz Palmowski

    Yearly mean and monthly smoothed sunspot number
    Yearly mean sunspot number (black) up to 1749 and monthly 13-month smoothed sunspot number (blue) from 1749 up to the present.

  10. Ireneusz Palmowski

    It is important to remember that the Sun is constantly evolving. The Earth is completely dependent on its Star.

  11. Ireneusz Palmowski

    The strength of the solar polar field as of 2023.07.14.

  12. A very interesting – and welcome subject.

    There are some points of particular interest, on which I have a couple of comments.

    “solid Earth geophysics community”. The word ‘solid’ looked very out of place. From a somewhat layman/engineer perspective, the earth is not a solid. Leads to the following:

    Having worked with rotating masses for a living, one rotating beast which was supposed to be solid was in fact making abrupt changes to its form and changing abruptly its characteristic vibration signature. In dynamics there is also the step function where what was before does no longer apply for what came later. The earth is also subject to such changes.
    Which agrees with “a causal (forcing) relationship that can only work one way. The components one finds in sea level, pressure, temperature… must arise from a causal chain going (1) from Jovian planets to the Sun
    (or directly to Earth), then (2) to inclination changes in Earth’s rotation axis, with (3) consequences on insolation changes-”

    The ancient ‘giants’ also wrote of such; Berossos and others. Plato was very clear, with a ‘declination of the heavens’. And others more recent such as R R Newton.

  13. Interesting article.

    See also: Yndestad H. 2022. Jovian Planets and Lunar Nodal Cycles in the Earth’s Climate Variability Frontiers in Astronomy and Space Sciences. May 10. 2022. — ————————————————————————————— “This study suggests that Earth’s global temperature variabilities starting in 1850 and Greenland temperature variabilities starting in 2000 B.C. have solar-lunar-forced stationary temperature cycles up to 4450 years.

    The primary causes of the identified multidecadal temperature variation is the stationary orbital cycles from the Jovian planets (Jupiter, Saturn, Uranus, Neptune) and the 18.6-year lunar nodal cycle from the Earth’s axis nutation.”

    And the Suns SIM movements- bringing it closer to earth in Spring equinox:

    “…This extra-deposition of solar radiation can account for the most terrestrial heating of the Earth in the past few decades…”

    “The current phase of Hallstatt’s cycle reveals it started from 1600 and will last until 2600. In this millennium the Sun is getting closer to the Earth (and other planets) orbit at the spring equinox leading to a significant (up to 20-25 W/m^2) extra-deposition of solar radiation to the Earth.”

    “… This type of periodic variations of solar irradiance and the terrestrial temperature caused by SIM has significant amplitudes of the additional solar forcing and, therefore, should be accounted for in the medium-term climate variation predictions.”

    “Therefore, the inclusion of solar and planetary influences in regional models is recommended.The Earth’s climate is a complex system that is affected by many factors that influence each other.”

  14. “In all these series we could recognize the signatures of the four Jovian plan ets (Jupiter, Saturn, Uranus and Neptune): i.e. their periods of rotation and many of their “commensurable” periods. This argues for a mechanism involving exchanges of angular momentum between the Sun, Earth and planets.”

    I found major mid latitude heat and cold waves occurring at syzygies and quadratures of Jupiter, Saturn, Uranus and Neptune. Cold events when Jupiter is opposite Neptune, warm events when Jupiter is square to Neptune. Hot events when Saturn is opposite Neptune, cold events when Saturn is square to Neptune. And the hottest events when Saturn is opposite Neptune with Jupiter roughly square to them both. Like in 1540, 1757, 1936, and 2006. This argues for a mechanism involving magnetic linkages, especially as the bodies exhibit distinct polarities.

  15. Robert David Clark



    The internet says a very large section of the Brunt Ice Shelf broke off 7 months ago. Maybe the effects of that melting from the bottom up is what will overcome the fast heat removal from the atmosphere and the record high temperatures around the earth will settle down soon.
    It has been almost 12 months since the sun began warming!!!!!

  16. How can the “Maunder Minimum” be explained where for about 60 years there were virtually no sunspots observed by astronomer E. Walter Maunder? This phenomenon resulted in the “little ice age” on Earth from 1645 to 1715. Could it happen again?

  17. Ireneusz Palmowski

    Even on Neptune the weather depends on the solar wind.

  18. No one has mentioned the US CRN data which show rural temps being flat since 2005. Why is this so under publicized even here?

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  21. Ireneusz Palmowski

    The amount of heat under the equatorial Pacific is falling fast.

    • Most interesting. The Niño appears to be pettering out. I hope we don’t have an abortion. I forecasted a normal Niño, but this is being a very weird year, climatically speaking.

  22. The work by Courtillot’s group is extremely important. I’ve read many of the papers in that list and I cite a couple in my book.

    The movements of the Earth are extremely important for climate. The fact, demonstrated many times in the past 50 years, that the Earth’s rate of rotation is affected by the solar cycle is enough to dismiss the silly idea that the variable Sun has an insignificant effect on Earth’s climate.

    I think Vincent is correct when he points to the conservation of the angular momentum as an essential factor in celestial mechanics whose effect on climate is completely neglected.

    The atmosphere rules the climate. The changes in the distribution of angular momentum between the atmosphere and the solid Earth reported by the changes in Earth’s rate of rotation, measured as changes in the length of day, indicate changes in atmospheric circulation responsible for the effects of the changes in climate that are taking place. I know, I’ve used the word “changes” five times in the same phrase. I don’t usually do that, but I just got out of bed and there’s no cofee in my veins yet.

    I find Courtillot’s group work insightful and important, and recommend reading their papers. Climate scientists are so self-centered that they are ignoring the important contributions coming from other scientific disciplines, geophysics in this case, but also ecologists with their studies on climate regimes, that led to the discovery of the 1976 climate shift in the Pacific, and are being since then ignored because they don’t fit the popular CO2 hypothesis.

    • Javier

      More than once I’ve wondered how many lost hours of research and lost opportunities to actually work on new ideas because of the group think that’s so pervasive in climate science. The establishment hasn’t aced the exam but they are so confident they have that there’s no initiative to seek out alternative explanations.

      Maybe future generations will be forced to do just that.

      Have another cup of coffee.

    • The 1976-1977 climate shift in the Pacific is associated with a shift from positive to negative Arctic Oscillation regimes, while the all popular climate circulation models predict increasingly positive Northern Annular Mode conditions with rising CO2 forcing. The sharp drop in the solar wind temperature from late 1976 makes the most sense.

  23. Ireneusz Palmowski

    The position of the four major planets affects changes in the position of the center of rotation of the entire solar system and the angular momentum of the Sun.
    I’m curious if the magnetic connections of the giant planets can cause gravitational interference. The solar wind shows that gravity and magnetism have a lot in common.

    • “The solar wind shows that gravity and magnetism have a lot in common.”

      You seem to be working toward a unified theory of forces. There’s a Nobel Prize at the end of that.

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  25. Just as our ancestors sought to understand the motions of the heavens in order to maximise their survival mechanics so it passes that if we look deeper into the patterns of what we do know and understand we will reach out and uncover the secrets to making the right choices at the right times.

    And this from knowing the right things we need to know, not because some ego tell us so, but because our individual free thinking intelligences tell us so.

    This article is so much more a rewarding read than the specious drivel that infests most every climate alartmist paper published in the past several decades.

    • From UK-Weather Lass > first paragraph. Very apt and nicely said.

      a) collectively experienced events with tragic consequences make myths via a mechanism of symptomatic relief,
      b) the historical character of the myth demands a cryptographic detection many generations after the initial event,
      c) perhaps both the myth-teller and myth-hearer want the truth to remain concealed,
      d) this concealment may reinforce symptomatic relief from the dreadful event and
      e) the duration of pain after the event (for many generations ahead) interrelates with the therapeutic mechanism.

      b) and c) need to be carefully ruminated on.

      My own interest in the subject matter has confirmed to me that Dr Laoupi is very correct (except for comet/meteor read nearby planets). We can look deeper because we inherit a host of mathematical tools that allow to decrypt the hidden knowledge. Newton’s law of gravitation makes clear which planets are troublesome.

  26. Also hoping a scientific attitude prevails but we must be willing to accept simple facts. For example, Tesla’s 98 Bay supercharger facility.

  27. Ireneusz Palmowski

    After a temporary increase in geomagnetic activity, the solar wind speed will drop sharply. This will result in the inhibition of zonal circulation at high latitudes.

  28. I don’t know if this study was cited, but I would appreciate Judith’s comments about the weight that should be given to it.

    • Satellite measurements don’t suffer from urban effects. UAH reports 0.14C/decade in the lower stratosphere. It cannot be much more than that at the surface, particularly since models say the atmosphere should warm more than the surface due to the change in the lapse rate (lapse rate feedback).

      • Typically land based measurements are showing more warming than the satellites – RSS or UAH, and I think the implication is that the difference can be accounted for by UHI.

  29. I have used both Singular Spectrum Analysis (SSA) and Complete Ensemble Empirical Mode with Adaptive Noise (CEEMDAN) to decompose temperature times series with frequently near same results.

    All decomposition methods have limitations. While SSA requires no a priori parameters, it does assume, at least, weak stationarity and requires selecting a value L for the number of require principal components. CEEMDAN is an empirical method that does not assume stationarity nor linearity. CEEMDAN has been one of a sequence of several improved versions of the original Empirical Mode Decomposition (EMD) method with versions of improvement beyond it.

    Lately hybrid decompositions are more commonly used that, for example, might combine CEEMDAN, SSA and a neural network method. All of the above leads to a question for the authors of this thread: Have you investigated other decomposition methods, if only to look for similar results or one the gives better predictive values?

  30. I find the correlations between climate parameters and small changes in the earth’s rotation parameters quite interesting. But is there an important new primary cause of climate change here, as some would like to believe? I don’t think so.

    That there should be correlations between millisecond variations in the length of a day and, for example, sea level rise is not surprising when you think about it. Rising seas, taller forests fertilized by extra CO2, even more water vapor in the upper atmosphere all raise the earth’s moment of inertia. More of the mass is at larger radii. Just as a spinning skater slows down by extending her arms, the earth’s rotation slows down every time a skyscraper is built. A quick calculation shows that indeed a sea level rise around 10 cm would increase the length of a day by a few ms, in order to conserve angular momentum.

    The authors recognize that redistribution of mass is the standard explanation for the correlation, but then challenge that argument. I have not read all the papers, but Ref 7 discusses it a bit. The SSA analysis apparently shows a lag between shifts of the pole and sea level rise, leading to the odd conclusion that a rotation axis shift from astronomical causes caused the seas to rise. I cannot critique the math of that result specifically, being unversed in SSA. But I am quite familiar with bad analyses about temperature rise in the industrial age preceding CO2 rise and therefore causing CO2 rise by ocean outgassing. (The oceans, of course, have been net sinks of CO2 throughout the industrial age.) I think we have another case here of misattributed causality.

    In pondering whether climate change causes rotation shifts, or rotation shifts cause climate change, I would ask the authors two questions:
    1. How do ms changes in lod warm the earth? You say by effecting solar input. But a graph in an earlier Curry post showed satellite measured solar input to be dead flat.
    2 How could mass redistribution by, say, sea level rise fail to effect the rotation kinematics by angular momentum conservation?

    The causal connection is clear and not what these papers claim. While they are an interesting set of papers, I cannot agree with Dr. Curry that they are important.

    • I am not one of the authors, but I can add some comments to what you say:

      “is there an important new primary cause of climate change here, as some would like to believe? I don’t think so.”

      Science is not about beliefs. Throughout history, people have believed that their knowledge was sufficient, while past knowledge was not. But the passage of time shows that knowledge is always inadequate. We are missing a major cause of climate change and we know it. There was a major forcing at work during the LIA – just 300 years ago – that we don’t know about, and there’s no reason to think it’s not at work today.

      Donohoe, A., et al. “The relationship between ITCZ location and cross-equatorial atmospheric heat transport: From the seasonal cycle to the Last Glacial Maximum.” Journal of Climate 26.11 (2013): 3597-3618.

      “the southward ITCZ shift on the order of 5° during the Little Ice Age suggested by Sachs et al. (2009) implies an AHTEQ change of approximately 1.7 PW; presently, there is no known climate forcing or feedback during that time period that could account for such a large energy perturbation at the hemispheric scale.”

      So, an important new primary cause of climate change is missing.

      “1. How do ms changes in lod warm the earth? You say by effecting solar input.”

      You assume that it is the change in the Earth’s rotation that should be responsible for the warming. ms changes in LOD report a shift in the exchange of angular momentum between the atmosphere and the Earth. It indicates a global change in the atmospheric circulation. This circulation regulates how much heat goes from the ocean to the atmosphere and how much is transported to the polar regions, where energy is lost more efficiently due to a very weak greenhouse effect.

      The 1976 climate shift that started global warming (it was cooling before) involved an abrupt change in atmospheric angular momentum and wind torques, not in atmospheric CO2, which was increasing very slowly by today’s standards.

      Marcus, S.L., et al., 2011. Abrupt atmospheric torque changes and their role in the 1976–1977 climate regime shift. Journal of Geophysical Research: Atmospheres, 116(D3).

      This and much more in my forthcoming book.

      • “ This and much more in my forthcoming book.”

        A tease. If it’s anything like your previous book, it will be a great read. Looking forward to its release.

      • Javier:

        “The 1976 climate shift that started global warming (it was cooling before) involved an abrupt change in atmospheric angular momentum and wind torques”

        NO! The climate shift was due to global Clean Air efforts (which began in the mid-1970’s) to decrease dimming industrial SO2 aerosol emissions because of Acid Rain and Health concerns.

        “Gridded” Industrial SO2 aerosol emissions (and others) are tracked by the Community Emissions Data System of the University of Maryland (CEDS), and are available from 1770 to 2019, and clearly show increasing temperatures as SO2 levels decrease.

        They peaked at 136 Million tons in 1979, and fell to 72 million by 2019, undoubtedly lower by now.

      • Javier

        Much higher up the discussion section there’s an entry by Burl Henry:

        ‘The Maunder Minimum had NOTHING to do with the Little Ice Age

        See: “The Definitive Cause of Little Ice Age Temperatures”

        He suggests that volcanic emissions of sulphur dioxide was the prime cause of decreased temperatures in the LIA.

        So I guess someone could ask the question: ‘can Volcanic eruptions of certain types cause a shift in the ITCZ?’

        I’m not supporting or opposing any argument, I just saw a potential connection and raised it for those with greater knowledge than me to consider.

      • rtj,

        Volcanic eruptions don’t have a significant effect on climate, they just affect the weather for 5-6 years. We have abundant data and proxies for the 1815 Tambora eruption, the most powerful in a thousand years, and that is what they show.

        The volcanic hypothesis of the LIA has no supporting evidence, Looking at volcanic sulfate in the GISP2 ice core it becomes very clear that the LIA had very low volcanic activity by Holocene standards.

        The period 1350-1760 had only two strong eruptions in 1452 & 1458. The 20th century had more volcanic activity than these 400 years of the LIA.

        The strongest cluster of volcanic eruptions during the LIA was the one made by the eruptions of 1809, 1815 (Mt. Tambora), 1822, 1835, and 1843, one of the largest groups of strong eruptions in 2000 years. It was followed by warming from the late 1840s onward, just a few years later, causing the end of the LIA.

      • Javier:

        You say that there is no supporting evidence for the LIA being caused by volcanic activity.

        There is irrefutable evidence that it was caused by volcanic activity!

        Every LIA temperature decrease noted in the Central England Instrumental Temperatures Data set (1635-present) coincided with a known volcanic eruption somewhere around the world, except for 2 or 3 probably sea-bed eruptions.

        The majority of the temperature decreases were due to VEI4 eruptions, whereas your reference wrongly considered only VEI5 or larger eruptions.


      • Javier: Add Krakatoa 1883

        The LIA (peak ~1680ce) coincides with the root of the Eddy cycle (Nature unbound IX fig 122). The detrimental effect of the roots of this cycle can be historically traced back to 6200bce. Including the abrupt turnarounds of the temperature anomaly; polar and equatorial.

        And at the root of it all is celestial mechanics.

        Another point about LOD. The monthly changes in lod can be traced back to the moon. The change in the trend reverses always on the new moon or the full moon. It is abrupt. The tidal effect of the moon (the moon’s orbital position; in conjunction) on the earth’s crust affects the moment of inertia of the earth around the Z axis; the axis of rotation. The atmosphere is of same effective thickness as crust but much lighter – so likely of no effect in lod (IMHO again: use newton’s formula of gravitation; on the atmosphere component and the crust component. There is however a gravitational effect on atmospheric water vapour; a thermo effect )

      • “Every LIA temperature decrease … coincided with a known volcanic eruption somewhere”

        Coincidence is not evidence.

        Besides there are always several eruptions every year somewhere.

      • Before you infer a transport of angular momentum from the solid earth to the atmosphere from a longer lod, be sure to take into consideration calculable increases in the moment of inertia of the earth from known mass redistributions.

      • Javier,
        The Marcus et al 2011 paper you reference ends with the following statement:

        “It should be noted, however, that the globally averaged heat fluxes associated with these oscillations are quite small compared to the planetary radiative imbalances arising from global warming [e.g., Hansen et al., 2005]; thus the observed decadal variations in GMST rate, which may temporarily reinforce or cancel longer-term trends, should not be interpreted as altering the underlying reality of anthropogenic climate change.”

        In other words, Marcus recognizes that he is trying to understand the “noise” in the GMST record, not the overall positive trend. My impression is that you wish to characterize the “small wiggles” as the dominant trend. Can you please tell us whether that is the case?

      • From David Andrews “Before you infer a transport of angular momentum from the solid earth to the atmosphere from a longer lod”

        This is an important point and reflects also on other comments. First, the earth is not a solid. The outer crust rests on a non-solid mantle and on liquid core. It is also very fractured. The gravitational effect of the moon has a distorting effect on the earth’s geoid. One is the lod change during full or new moon. (Caution here: it may not be due to momentum, but also due to earth gyro response. Ie induced tilt and precession change)

        However that is not all. When stresses build at fractured sites due to distortion stress release may occur and result in earthquakes. Geoid distortion cause also stress release via volcanic eruptions. Both event types are a response to an external driver. Such an instance was anticipated for the full moon of February – a test case-. Earth saddled by full moon on one side and rest of solar system on other. Anatolia faced the moon as it transited the conjunction line. Anatolia is a fractured piece of earth surface with a very ugly history from prehistoric times (around 2345bce; a fourth Eddy root from the LIA. What then resulted in the 4k2 event period with all that came with it).

        As to evidence – for the 4k2 event- see here:
        and supported by here:

        The atmosphere in comparison has negligible weight, especially the small part where it happens to face the moon.

      • “Before you infer a transport of angular momentum from the solid earth to the atmosphere from a longer lod, be sure to take into consideration calculable increases in the moment of inertia of the earth from known mass redistributions.”

        That is the work of experts. There’s ample bibliography on the effect of atmospheric angular momentum changes on Earth’s rotation rate.

      • “It should be noted, however, that the globally averaged heat fluxes associated with these oscillations are quite small compared to the planetary radiative imbalances arising from global warming [e.g., Hansen et al., 2005]; thus the observed decadal variations in GMST rate, which may temporarily reinforce or cancel longer-term trends, should not be interpreted as altering the underlying reality of anthropogenic climate change.”

        Marcus et al. don’t know the global climatic implications that the global changes in atmospheric momentum they are studying have, so this is just their opinion.

        They are unaware of the abundant evidence coming from many studies outside their specialty that indicate the outstanding importance of these type of abrupt shifts in global atmospheric circulation that happen every few decades. It is too long to detail in a comment. It is in my forthcoming book to be published in a couple of months.

        The undemonstrated idea that internal variability does not affect long-term climatic trends should not be assumed and is not universally accepted by scientists.

        For example, Chylek, P., et al., 2014. Geophys. Res. Lett. 41 (5), 1689–1697, say:

        “The anthropogenic effects account for about two thirds of the post-1975 global warming with one third being due to the positive phase of the AMO.”

      • melitamegalithic said

        “The LIA (peak ~1680ce) coincides with the root of the Eddy cycle (Nature unbound IX fig 122). The detrimental effect of the roots of this cycle can be historically traced back to 6200bce.”

        Around 6200 BC was a high solar period, with strong trade winds, implying positive NAO/AO regimes, and saw great expansions in human settlements from the Indus through to England. 3453 (4×863) years later during the next coldest period in Greenland from around 2750 BC saw city building take off worldwide. Another 3453 years later during the next coldest period in Greenland in the 700’s AD, were the warmest northern European summer temperature of the MWP (Esper 2014).
        Eddy is too long, the real solar cycle is 863 years, for the high solar periods, and for the grand solar minima series. Every fourth high solar period at 3453 years was evidently stronger through the Holocene. Go back in 863yr steps from the LIA start at 1215, and at 4 steps back you’ll see the 4.2kyr event.

      • Ulric Lyons:

        Eddy cycle is variously given as 980 years or 975+\-50 years. Neither appears right because the cycle appears to be frequency modulated and triggered. It varies some. However four cycle lengths from LIA at 1680ce to 2346bce (this is a precise date) gives on average a cycle length of 1005 years. For 8 cycles from 1680ce to 6200bce it is 985 years.

        Some dates from my own research material:
        Eddy events and dates linked to known civilisations:
        Ascendance: Akkad/Sumer 2700 BCE
        Aegean 1700 BCE
        Phoenician/Greek 800 BCE
        Roman Warm Period 180 CE
        Mediaeval WP 1160CE

        Collapse: Akkad/Sumer 2200 BCE (4k2 event)
        Aegean 1300 BCE (Sea People)
        Phoenician/Greek 300 BCE (earthquakes Helike)
        At an earlier era, from this writer’s research and some confirmation from archaeology, there is indication of the times of collapse of an earlier civilisation that thrived in the Maltese islands.
        Earlier era: Maltese Temple period ~3200 BCE (first clear destruction – tectonic rotation)
        Maltese Temple period ~2300 BCE (final)
        An earlier possible destruction date is 5200bce (tectonic rotation).
        Many times change begins to bite near/within a century after the event. Also it is not a solar cycle but planetary influences.

      • melitamegalithic,
        Measuring from 2346 BC or 6200 BC to 1680 are both red herrings as neither are during centennial solar minima like 1680 is.
        The 863 year cycle is real, and varies by +/- 20 years, and because it is possible to discretely map each centennial solar minimum from 4700 BC to 10,000 AD, that variability can be modeled and predicted. It can also correct solar proxies which lack the grand solar minimum from 350 AD (The Early Antique Little Ice Age).

        The Eddy cycle has no theoretical or empirical origin, and it is far too long, it’s wrong.

      • Ulric Lyons

        As I told you, it is planetary not solar.

        It appears you came up with an interesting date, 350AD. On a hunch i did some trawling. Look up that number here:
        Look up the number 350AD in the text; a ‘change point’.
        That year provides some very interesting planetary alignments/orientations (in fact similar to 173CE and 2346bce). Change is abrupt -very-, but cannot yet narrow the precise date to near the day from the info provided.

      • U Lyons

        Additional: compare also lake sedimentation as in my above link. repeated here

        Note the date 350ce, with a peak in sedimentation rate at a different location (Spitsbergen). We do not have a historical measurement of earth tilt between 178ce and 450ce, however the ‘ant trail’ indicates there is an inflection point in between. The next inflection point is at 600ce, an Eddy root. Times around these periods in the cycle have always been dire. Peaks have been times when humanity had had it good.

      • melitamegalithic
        Planetary is solar, Jovian configurations are associated with either warmer or colder events, at seasonal to inter-annual scales. There is a good heliocentric analogue for 173 AD in 1762, and for 352 AD in 1940. They have absolutely nothing to do with the grand solar minimum series from 350 AD.

      • Ulric Lyons:
        Not quite. Take a look at the obliquity curve in my link. Year 173ce was an identifiable disturbance. The last disturbance was a very minor one about 1670ce, preceding the LIA. There is nothing after that.
        Planetary alignment do effect the weather and there have been ample evidence of that in the past year. They also have a geological effect, equally demonstrated (see the alignments today). However they are not the bigger turnaround points.

        The last major one was in 2346bce. However measurements of obliquity only started in 1100bce, and the next in 350bce, so difficult to glean anything till then.
        These indicate the system is generally unstable and moves from one state to the other in jerks (abrupt). The last four glacial cycles demonstrate that. This one, so far, is no different.

      • If whatever happened in 173 failed to happen in 1762 at the same Jovian configuration, then it’s a spurious correlation and not evidence.

      • Do not miss the fact that obliquity in year 173ce was actually measured. (It is in reviewing the info that the outlier readings were in fact an event caught in the act; and subsequently confirmed by lake sedimentation research.)

        However you make an interesting point. Looking up planetary alignments for the two dates showed a similarity. But not quite. For year 173ce the conjunction of Venus and Jupiter is much closer. In year 1762 they do not match. And neither with new or full moon. The moon is essential.

        Your observation does sharpen the perspective of when and what is essential to trigger major events. Compare October 24 173 and the range Oct-Nov 1762 on a daily instance.

      • “For year 173ce the conjunction of Venus and Jupiter is much closer. In year 1762 they do not match.”

        No one can tell what you mean by that, or know whether it matters.

        “And neither with new or full moon. The moon is essential.”

        It isn’t essential for the ordering of solar activity, but if you are thinking along gravitational lines, the 17th Oct 1762 has Earth and a new Moon in line with the three inner gas giants, as on 24th Oct 173.

      • It is gravitation. The abrupt change in glacier ablation and lake sedimentation (year 173ce) did not arise from abrupt changes in solar activity. It is a disturbance of the earth’s orientation in space, as evidence in the readings of obliquity in that year.

      • Maybe, but there is no point in trying to associate 173 AD with the grand solar minimum from 350 AD.

      • 350AD is not being directly associated with 173AD, but you uncovered an interesting piece (from the POV of planetary alignments).

        The linked paper say ” a significant change-point of the occurrence pattern around 350 CE, switching from the overlay of two mechanisms of event recurrences of 5 and 50 years before to 2 and 17 years after this change-point.”

        In this new link: see fig4, no grand minima at 350ce. ??? (not an area I explored; it may be questionable how they are derived and what it all means.).

      • “350AD is not being directly associated with 173AD, but you uncovered an interesting piece (from the POV of planetary alignments).”

        You said 173 was similar to 350, 352 is closer. But the Jovian configurations alone are not responsible for the GSM from 350 AD. And yes as I said, it is missing from the solar proxies.

      • Yes year 352ce, late Nov, 1-3rd Dec is much closer (it is another killer orientation). The paper referring to year 350ce did say around, apparently arrived at from sediment cores. So there would be some error spread in that figure.
        From paper “2.2. Sedimentary flood record data
        For our analysis we use flood frequency data from sediment records that had been recovered from Lake Mondsee sediments
        [19–22]: Multiple cores had been retrieved during three coring campaigns (2005, 2007, 2010) “. If it was so evident at that point in the cores, then something abnormal did happen.

  31. ‘…anthropogenic and “natural and anthropogenic” fits failed to capture the mid-19th-century or mid-20th-century warm periods, while the solar and “natural only” fits failed to capture the mid-19th-century warm period and the most recent part of the current warm period. Therefore, if the “rural-only” series is correct, additional climatic drivers to those considered by this analysis and the IPCC’s equivalent attribution analyses have yet to be included.’

  32. ref 3, again.

    Common errors made in this type of study.

    1) Deciding on a mechanism without direct evidence, which can render making observations of critical correlations impossible.
    2) Invoking a fixed length Gleissberg cycle of centennial solar minima, when the record show that the intervals vary between 7 and 12 solar cycles. The AMO varies between 40 and 70 years because of that. A 59.58yr Jupiter-Saturn trigon may look pretty but it explains nothing.
    3) Assuming that the physics involves various frequencies modulating each other, rather than a series of discrete heliocentric angular events which define the absolute variability of solar cycles and centennial cycles.

  33. Ireneusz Palmowski

    Why do we have heat waves in North America and Europe? When the solar wind weakens, the speed of the jet stream current at high latitudes also weakens. The jet stream descends in the eastern Pacific and Atlantic, forming meanders. The curves over North America and Europe form stable highs with warm air from the south. Water vapor in these highs remains gaseous and reduces the vertical temperature gradient. The surface warms up so much that the temperature drop is not strong at night.
    It is the jet stream in the tropopause that creates the major highs and lows.

    • Weak solar wind episodes associated with negative North Atlantic Oscillation conditions can promote Spanish and Saharan plumes. These are very brief at around 2-5 days, but often have the highest daily maximum temperatures, and very low daily minimum temperatures, due to low humidity.
      Stronger solar wind states and the associated positive NAO conditions are required for the longer duration major heatwaves.

  34. Ireneusz Palmowski

    In the current solar cycle, the solar wind is rippling. A brief increase in speed is followed by a sharp decrease.

  35. Speaking of Celestial Mechanics, the eclipse next month may tank the Texas grid.

    Texas quickly spiraled into a power emergency on Wednesday night when record September demand and a drop in supply prompted appeals to consumers to conserve electricity to avoid blackouts. Hot, humid weather put the squeeze on the grid, but another challenge looms next month: a solar eclipse that could slash output and create an unprecedented test for the embattled grid.

    The Electric Reliability Council of Texas, or Ercot as the state grid operator is known, suddenly declared a Level 2 emergency because reserve capacity had fallen to less than 1,750 megawatts. The heartbeat of the grid — measured in hertz — also fell perilously low, according to the grid operator. These conditions and the quick escalation of the grid emergency shocked generators, consumers and power experts alike.

  36. Dr. Courtillot, you say:

    We first applied the method to the series of sunspot numbers. The series could be satisfactorily reconstructed from simply a (rather flat) trend and two components with periods 11 years (Schwabe cycle) and 90 years (Gleissberg cycle). More interestingly, these components allow one to construct a precise and robust model of solar activity and to predict (so far rather accurately) the ongoing sunspot cycle and beyond [ref 1, 2, 3].

    Intrigued by this claim, I looked at your ref 1, wherein I found your prediction for the current sunspot cycle, viz:

    We conclude with a prediction of Solar Cycle 25 that can be compared to a dozen predictions by other authors: the maximum would occur in 2026.2 (± 1 yr) and reach an amplitude of 97.6 (± 7.8), similar to that of Solar Cycle 24, therefore sketching a new “Modern minimum”, following the Dalton and Gleissberg minima.

    So I graphed up your prediction against the current sunspot record. Here’s that result:

    As you can see, at this point it’s quite clear that your prediction was not only wrong, it was wildly wrong … so I’m curious why you haven’t dealt with that failure before claiming success for your method.

    Best regards,


    • Willis

      Excellent analysis. Thanks

    • I’m still waiting for Dr. Courtillot’s reply, but while we twiddle our thumbs, does anyone else have an explanation of his claiming success for an obvious failure?

      I hate climate “scientists” who are unwilling to debate and defend their own work.

      And yes, Dr. Courtillot, that means you … how about you stand up and defend your claims?


  37. Javier,
    Responding to your Sept 7, 7:56 am post:
    Your reference Chylek et al (2014) indeed concludes that Global Mean Surface Temperature (GMST) increases since 1970 are about 1/3 due to the Atlantic Multidecadal Oscillation (AMO), and 2/3 due to anthropogenic influences (greenhouse gas increases plus aerosol reductions). I will accept that. But I argue below that you should NOT consider the AMO to be a primary source of global warming, only a relatively short-term influencer of GMST rise.
    I don’t think I need to document in detail that most of the excess heat from the global radiative imbalance in the industrial age has gone into the oceans: 91% according to a NOAA estimate. (I will find some primary sources if you want to contest that.) This accumulated and growing energy inventory is in many ways a better measure of current global warming than “GMST”. Exactly how it influences measurements of GMST in any particular year must be complicated. Surely that depends among other things on ocean and atmospheric circulation patterns, that may or may not be cyclic. But heat released (or absorbed less efficiently) by the oceans, more in some years than others, should not be thought of as a new primary cause of global warming. Since we are currently in a positive AMO phase, we can consider that the radiative imbalance of a couple of decades past is just now being detected through GMST algorithms.
    I was wrong in an earlier post to suggest that studies of changing circulation patterns are unimportant. It is very important to understand the wiggles in GMST growth which, if they endure for decades and are ignored, distort our understanding of the rate of global warming. But I will repeat my earlier comment that nothing I have read so far convinces me that planetary mechanics has anything to do with decadal circulation changes. The certain changes in the earth’s moment of inertia from known consequences of global warming (e.g., sea level rise) account for the interesting correlation between lod and climate.

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