100,000 yr cycle ..The MILANKOVITCH CYCLE

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Vostok ice record time series
The graph above shows 420,000 years of ice core data from Vostok, Antarctica research station
The sequence forms a sawtooth wave form

    Some background reading


Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volumeAyako Abe-Ouchi, Fuyuki Saito, Kenji Kawamura, Maureen E. Raymo,Jun’ichi Okuno, Kunio Takahashi & Heinz Blatter
August 2013

    Main points

-statistical tests have demonstrated that the glacial cycles are indeed linked to eccentricity, obliquity and precession cycles
– Yet insolation alone cannot explain the strong 100,000-year cycle, suggesting that internal climatic feedbacks may also be at work
-The responses of equilibrium states of ice sheets to summer insolation show hysteresis ….with the shape and position of the hysteresis loop playing a key part in determining the periodicities of glacial cycles

– C02 is not the driver of the 100,000 yr cycle

THe feedback process and loop is described in the abstract

    Article link
Thanks to this website for the notification of this research

Another article on this same topic but paywalled at SCIENCE
How to Make a Great Ice Age, Again and Again and Again
Richard A. Kerr

For more than 30 years, climate researchers have been trying to figure out how slight changes in Earth’s orbit could drive the great ice ages. Now the best computer model of the ice ages yet may have found the answer:
a rhythmic stretching of Earths egg-shaped orbit around the sun every 100,000 years amplifies the influence of a second orbital cycle.


9 comments on “100,000 yr cycle ..The MILANKOVITCH CYCLE

    and other fluctuations in Earth’s Orbit

    Nice explanations and diagrams here

    multiple cycles overaly milankovitch
    This web site is privately owned, totally independent, and not associated with any religious group or political organization

    the 71,000-year orbit precession causes a 41,000-year oscillation in the tilt of the earths axis, about plus or minus 1.3 degrees from its average value of 23.3 degrees. This number is not absolutely stable – it depends on the combined positions of all the planets through time.

    Periodic Fluctuations in Earth’s Orbit About the Sun

    The advance and retreat of ice sheets during times of icehouse climate appears to be strongly influenced by three periodic fluctuations in Earth’s orbit about the sun.

    The eccentricity (deviation from a circle) of Earth’s elliptical orbital path around the Sun varies in a cycle of approximately 100,000 years. A greater amount of eccentricity means that Earth-Sun distance varies substantially over the course of a year from perihelion (closest approach to the sun) to aphelion (orbital point farthest from the Sun).

    The Earth is currently tilted 23.45° from a perpendicular axis to Earth’s orbital plane about the Sun.
    The axis is tilted in the same direction throughout a year; however, as the Earth orbits the Sun, the hemisphere tilted away from the Sun will gradually come to be tilted towards the Sun, and vice versa. This effect is the main cause of the seasons. Whichever hemisphere is currently tilted toward the Sun experiences more hours of sunlight each day, and the sunlight at midday also strikes the ground at an angle nearer the vertical and thus delivers more heat.

    As Earth progresses in its orbit, this axial tilt creates the familiar seasonal variation (northern winter occurring when the north pole is tilted away from the Sun).

    The Earth’s axial tilt varies between 21.5° and 24.5° with a 41,000 year periodicity (currently decreasing: 24.049 in 3300 BC, 23.443 in 1973, 23.439 in 2000)

    The third and final cyclical change in Earth’s orbit (with a period of about 26,000 years)

    100,000 yrMilankavitch cycle

    large cycles

    Eccentricity – Orbital shape
    Over a 95,000 year cycle, the earth’s orbit around the sun changes from a thin ellipse (oval) to a circle and back again

    Obliquity – Axial Tilt
    On a 42,000 year cycle, the earth wobbles and the angle of the axis, with respect to the plane of revolution around the sun, varies between 22.1° and 24.5°

    Precession – Axial Orientation

    12,000 years from now the Northern Hemisphere will experience summer in December and winter in June because the axis of the earth will be pointing at the star Vega instead of it’s current alignment with the North Star or Polaris. This seasonal reversal won’t happen suddenly but the seasons will gradually shift over thousands of years.

  2. What I would like to see Weather Cycles is a study that would prove which cycles or cycle accounted for 100% of the abrupt temperature drop at the start of the Younger Dryas and what specific cycles or cycle accounted for the abrupt rise in temperature at the end of the Younger Dryas?

    I have yet to see a detailed explanation as to what cycles or cycles caused the abrupt beginning and ending of the Younger Dryas and why those cycles were unable to replicate this once this period came to a close?

    Why? Thanks

    Youngar dryas
    picture for those new to this

    This link SDP has a cycle graph showing the constructive and destructive alignments of 3 of the longer cycles.
    This is not an area l am well versed in but the point l make is that the cycle overlay is represented here

    they site the overlay and abrupt climate change is caused by 3 major cycles .
    100, 000 eccentricity cycle
    41,000 obliquity cycle
    23,000 procession of the equinoxes

    If you zoom into the period of rapid change to you can see the 3 cycles are constructively aligned in the downward phase.

    Actually since 1998 we have 4 smaller cycles coinciding in a downward phase
    the Schwabbe ~11 , Hale ~22 , AMO/~66yr , and the down half phase(103 yr) of the DeVries(206 yr)

    I did not mention previously that the longer (1,000-1500?) yr cycle l believe is on its way UP !.
    So this will temper any cooling below a Dalton / Maunder in the next 100 yrs


    Actually l have seen evidence of nesting in cycles
    1, 10,100, 1,000 , 10,000, 100,000

    If the phi theorem pervades the solar system these sequences might be infinite

  3. Folowing on from above post
    Thanks to Salvatore for this research abstract
    It is generally assumed that changes in ocean circulation forced the abrupt climate changes during the Late Pleistocene, including the Younger Dryas event. Recently, however, it was proposed that variations in solar irradiance could have played a much more prominent role in forcing Pleistocene climate changes. For climate fluctuations during the Holocene the role of solar variability as an important forcing factor becomes more accepted. Furthermore, two physical mechanisms were recently published that explain how relatively small changes in solar irradiance could have had a strong impact on the climate system. We discuss the possibility that an abrupt reduction in solar irradiance triggered the start of the Younger Dryas and we argue that this is indeed supported by three observations:
    (1) the abrupt and strong increase in residual 14C at the start of the Younger Dryas that seems to be too sharp to be caused by ocean circulation changes alone,

    the Younger Dryas being part of an ∼2500 year quasi-cycle — also found in the 14C record — that is supposedly of solar origin,

    (3) the registration of the Younger Dryas in geological records in the tropics and the mid-latitudes of the Southern Hemisphere.
    Moreover, the proposed two physical mechanisms could possibly explain how the North Atlantic thermohaline circulation was perturbed through an increase in precipitation together with iceberg influxes. In addition, the full magnitude of the Younger Dryas cooling as evidenced by terrestrial records in Europe could be explained. We conclude that a solar triggering of the Younger Dryas is a valid option that should be studied in detail with climate models.

  4. Discussion on ‘tallbloke’

    Your description of the apparent chaos in the earths climate history as per say (the spikes up and down on a long time series graph) is a pertinent point. However signal analysis clearly reveals a high magnitude of order in BOTH solar system dynamics and Time series graphs of elements/variables of the Earths climate

    Chaos is no doubt embedded within the cycle transitions

    I find the mechanisms and links of solar system dynamics to the earth climate are far more difficult to decipher and confirm

    We can describe the solar system cycles as a cohesive clockwork, geared phenomena which can be mapped precisely into the past , now and into the future.

    The challenge is to make conclusive physical links to the planetary motion, solar, plasmas, electromagnetic, gravity , solar wind etc to the earths climate.

    I agree thresholds seem to play a large part in this puzzle . The saw tooth wave form is too frequently evident in earths historical data and just intuitively speaks thresholds

    If you can mathematically signal analyse the long history of our isotope time series and produce wave forms of a significant order . I think by mathematical definition the proof is order not chaos.

    Anyway. Found this graph. Showing the various variables that may effect glaciation cycles

    milankovitch cycles

    Looking at each factor. If l was to pick the best fit. I would choose ECCENTRICITY as the main driver and the other factors may affect or modify the amplitude of each event



  5. TOM MANGO has some great research on these longer cycles
    Here is a link to his discussion on the link of ice ages to the the sun and the gas giant planets jupiter and saturn.
    I especially like his discussion on the role of magnetic fields in this process and his questioning and critique of our current theory of the cause of ice ages
    Tom mango says”In my estimation, Milankovic theory ‘is’ completely turned around

    The earth’s inner core is continually cranked by an
    accelerating sun and a large moon. It’s axis swings up and down
    every 41000 years while it precesses (25772 yrs) like a football
    and i’ts eccentric orbit expands and contracts (100000 yrs). These
    are just a few of the motions the earth has inherited from an
    accelerating sun. They all have something in common, they cause
    the earth to produce an incredibly strong magnetic field.

    The most plausible explanation for re-occurring ice age cycles is:
    the substantial loss of magnetic field. Current Milankovic theory
    does not address the magnetic field. How light changes with a
    weaker field. How the chemistry of the atmosphere changes with
    different light. ( for more on this visit Reality348)
    Read all his posts on this topic here

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