Ice Ages

A collection of posts regarding glacial cycles.

  1. Phenomenology of Ice Ages
  2. Does the Moon trigger interglacials?
  3. Ice Ages – still a mystery
  4. The straw that broke the camel’s back
  5. The Moon’s eccentric orbit
  6. Lunar madness
  7. Tidal variations
  8. A challenge for climate models
  9. What causes interglacials? Part 1.
  10. Part 2: The real cause of Ice Ages ? – Resonant dust clouds ?
  11. Ice Ages revisited
  12. Evidence of variations in solar irradiance with Earth’s orbit
  13. Changes to Climate
  14. Does the moon trigger interglacials?
  15. Lunar Madness
  16. Tidal effects in Polar regions

4 Responses to Ice Ages

  1. John Reid says:

    I am a physicist with a background in statistics and spectral analysis. I have long been interested in climate “cycles” and I have come to the conclusion that, for the most part, we are actually dealing with red or pink noise. This is particularly true of the 100,000 year eccentricity eccentricity “cycle”. I believe the ice age “cycles” are band-limited red noise with small coherent signals at the obliquity and precession frequencies.

    See my blog http://blackjay.net and the pages “Pause for Thought” and “Bounded Random Walk”.

  2. John Reid says:

    See my latest post at http://http://blackjay.net/?page_id=93

    Beryllium 10 is produced in the stratosphere by collision of cosmic rays with atmospheric particles. Its production rate is therefore controlled by the primary cosmic ray intensity, by solar modulation and by geomagnetic modulation, all of which processes lie outside of the climate system. Comparison of the GISP2 10Be flux with GISP2 temperature variations suggest that different mechanisms underlie Dansgaard-Oeschger events, the Younger Dryas and Termination I. A model of ice age climate variations is proposed whereby the climate alternates between two metastable states.

    • Clive Best says:

      John,

      You write: “The random walk hypothesis of Hasselmann [1976] still applies but instead of a Gaussian white noise process due to weather, terminations appear to be forced by discrete impulses which occurred about 80 or 120 kyr apart, after each of which the climate relaxed exponentially back to its prior, ice age state. ”

      But we know that the 40 year cycle is the change in obliquity of the earth’s axis. When Obliquity is a maximum the arctic circle expands southwards. During summer both the northern and southern polar regions get more insolation. The 43,000 year cycle of obliquity is the only constant clock running over the last 3 million years.

      Until 900,000 years ago all glaciations ran on a 41,000 year clock. Since then they have been running first on a 2 step (80,000 year) and then on a 3 step 120,000y cycle. There may be a random component as well but it is not the main driver.

      You also show that Be10 coincides with D-O events implying that a change in cosmic rays coincided with these and that their origin is astronomic. But then you don’t follow that through and conclude finally that they are unexplained . Why ?

      So-called Bond events also seem to be related to D-O events.

      I am still looking for a causal relationship for Ice Ages.

  3. Steven Blue says:

    Aloha Clive:
    A causal relationship for ice ages exists. Unfortunately, the most probable cause is also the simplest, so it is too simple for academia and intellectuals. A Micronsian tree-trimmer can understand the highest probable cause of an ice age better than any ivory-tower PhDs.
    If you are interested and are capable of setting aside your pre-conceptions, then I will share the cause with you – a cause that I see everyday here in the tropics, and a cause that I can and do counteract, any time I want to do so. I have seen the action needed to counteract an ice age produce notable results in as little as 8 – 10 days. Simplicity intensifies!

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