Milutin Milankovitch

30-04-2021

Milutin Milankovitch

The Serbian astrophysicist Milutin Milankovitch is best known for developing one of the most significant theories relating Earth motions and long-term climate change. He dedicated his career to. Milutin Milankovitch, Serbian mathematician and geophysicist, best known for his work that linked long-term changes in climate to astronomical factors affecting the amount of solar energy received.

Milutin Milankovitch & Revised Julian Calendar
Milutin Milankovitch Biography

A letter to the editor in Nature Geoscience notes that this year marks the 100-year anniversary of Milutin Milankovitch’s (Milanković’s) book explaining how slow changes in Earth’s orbital and astronomical motions could affect its climate.¹ This book, entitled Mathematical Theory of Heat Phenomena Produced by Solar Radiation, laid the mathematical groundwork for what would become “one of the most influential scientific theories in climate science,”¹ known as the “Milankovitch,” or “astronomical,” theory of climate change.
This theory holds that slow changes in the tilt of Earth’s rotational axis and in the shape of its orbit cause changes in the seasonal and latitudinal distribution of sunlight, and that these changes in sunlight control the timing of ice ages. Ice ages are said to occur when summer sunlight striking the northern high latitudes becomes weaker, allowing ice sheets to grow. Warmer periods (or interglacials) are said to occur when this high-latitude, northern, summer sunlight is more intense. As noted in the Nature Geoscience letter, confirmation for this theory was a long time in coming: “The long-awaited confirmation [of the theory] arrived with James Hays and collaborators⁷ in 1976, who finally demonstrated that climate fingerprints in ocean sediment records contain the same temporal cycles as Milanković’s theory predicted [first footnote in original].”¹
The Milankovitch theory has many problems, the most obvious of which is the apparent difficulty of major climate changes being driven by small variations in the way sunlight strikes the Earth. Moreover, original ICR research demonstrated a serious flaw in an iconic paper titled “Pacemaker of the Ice Ages,” which purported to show evidence for the theory.^2-5 Summaries of this research are available on our website.^6-8
This apparent confirmation of the Milankovitch theory was critically dependent upon an assumed age of 700,000 years for the most recent flip—or reversal—of the Earth’s magnetic field.^2,9 This is because the date of this magnetic reversal was used to assign dates for the most recent ice ages, and these dates agreed with Milankovitch expectations. Yet uniformitarian scientists no longer accept this age assignment as valid: Today, they claim this reversal happened 780,000 years ago.¹⁰ Given that secular scientists claim the Earth is 4.6 billion years old, a difference of 80,000 years may not sound like much. However, the total timescales in the original paper were all less than 500,000 years, so this change of 80,000 years was large enough to knock the results “out of alignment” with Milankovitch expectations. This is true even if one accepts the vast ages claimed by secular scientists. Additional revisions to the data used in the “Pacemaker” paper made the disagreement even worse!^11,12
Uniformitarian climate scientists have, to the best of my knowledge, never publicly acknowledged this problem with the “Pacemaker” paper—either to the larger scientific community or to the general public. However, if one reads “between the lines,” a 1997 paper from Dr. Maureen Raymo appears to be an attempt to quietly “clean up the mess” and to provide an “alternate” justification for the claim that ice ages occur at the “correct” times.^13,14
Given the shakiness of the supposed supporting evidence, it is amazing that the Milankovitch theory remains one of the main arguments for catastrophic global warming!¹⁵ Partly on the basis of this supposed evidence for “climate change,” some are advocating for draconian environmental policies and regulations. This is a prime example of how erroneous beliefs about the past can have serious consequences in the present.
References
1. Cvijanovic, I, J. Lukovic, and J. D. Begg. 2020. One hundred years of Milanković cycles. Nature Geoscience 13: 524–525.
2. Hays, J. D., J. Imbrie, and N. J. Shackleton. 1976. Variations in the Earth’s Orbit: Pacemaker of the Ice Ages. Science. 194 (4270): 1121–1132.
3. Hebert, J. 2016. Revisiting an Iconic Argument for Milankovitch Climate Forcing: Should the Pacemaker of the Ice Ages” Paper Be Retracted?—Part 1. Answers Research Journal 9 (2016): 25–56.
4. Hebert, J. 2016. Revisiting an Iconic Argument for Milankovitch Climate Forcing: Should the Pacemaker of the Ice Ages” Paper Be Retracted? Part 2. Answers Research Journal 9 (2016): 131–147.
5. Hebert, J. 2016. Revisiting an Iconic Argument for Milankovitch Climate Forcing: Should the Pacemaker of the Ice Ages” Paper Be Retracted? Part 3. Answers Research Journal 9 (2016): 229–255.
6. Hebert, J. 2016. Milankovitch Meltdown: Toppling an Iconic Old-Earth Argument, Part 1. Acts & Facts. 45 (11).
7. Hebert, J. 2016. Milankovitch Meltdown: Toppling an Iconic Old-Earth Argument, Part 2. Acts & Facts. 45 (12).
8. Hebert, J. 2017. Milankovitch Meltdown: Toppling an Iconic Old-Earth Argument, Part 3. Acts & Facts. 46 (1).
9. Shackleton, N. J. and N. D. Opdyke. 1973. Oxygen Isotope and Palaeomagnetic Stratigraphy of Equatorial Pacific Core V28-238: Oxygen Isotope Temperatures and Ice Volumes on a 105 Year and 106 Year Scale. Quaternary Research. 3 (1): 39–55.
10. Shackleton, N. J., A. Berger, and W. R. Peltier. 1990. An alternative astronomical calibration of the lower Pleistocene timescale based on ODP Site 677. Transactions of the Royal Society of Edinburgh: Earth Sciences. 81 (04): 251–261.
11. Hebert, J. More Problems with Iconic Milankovitch Paper. Creation Science Update. Posted on ICR.org July 13, 2018, accessed September 24, 2020.
12. Hebert, J. 2017. The “Pacemaker of the Ice Ages” Paper Revisited: Closing a Loophole in the Refutation of a Key Argument for Milankovitch Climate Forcing. Creation Research Society Quarterly. 54: 133–148.
13. Raymo, M. E. 1997. The timing of major climate terminations. Paleoceanography and Paleoclimatology. 12 (4): 577–585.
14. See also the discussion in Hebert, J. 2019. The Climate Change Conflict: Keeping Cool Over Global Warming. Dallas, TX: Institute for Creation Research.
15. Hebert, J. 2019. Climate Alarmism and the Age of the Earth. Acts & Facts. 48 (4).
*Dr. Jake Hebert is Research Associate at the Institute for Creation Research and earned his Ph.D. in physics from the University of Texas at Dallas.

In the eyes of Milutin Milankovitch, there’s been a noticeable trend in climate, temperature and seasons due to this cycle. And we can accredit these long-term climate changes to 3 variations in geometry between the Earth and sun:

ECCENTRICITY: How the Earth orbits the sun.
OBLIQUITY: What angle Earth faces the sun.
PRECESSION: How Earth’s axis of rotation changes.

If you put these 3 interactions of Earth and the sun together, they form the Milankovitch Cycle. Let’s explore with more detail.

1. Orbital eccentricity

Earth revolves around the sun in a roughly circular orbit. But roughly every 100,000 years, its orbit becomes more eccentric.

So it starts as a circular orbit like it is in its current state. But like a pendulum, the eccentricity will swing it back the other way with a more elliptical orbit.

Because Venus is so close to Earth, its gravitational interactions slightly pulls Earth in its orbit. Then, colossal Jupiter pulls Earth slightly outside its orbit at the opposite end.

So Earth periodically goes from a circular orbit to a more elliptical one (high eccentricity). This is due to the gravitational pull of neighboring planets. Because of its orbital eccentricity, Earth varies in distance from the sun. As a result, it receives less solar radiation causing it to cool.

2. Obliquity variation

The next piece of the puzzle is obliquity. Right now, Earth’s obliquity is 23.5°. But during the Milankovitch Cycle, it varies from 22.1° to 24.5° and takes 40,000 years to complete a full cycle.

Earth’s changing obliquity doesn’t alter the total amount of incoming solar radiation. Instead, it affects the geographic distribution of where sunlight hits the Earth.

AXIAL TILT: For example, if axial tilt increases, winters are colder in both hemispheres. And vice versa for when axial tilt decreases.

In summary, more tilt signifies more severe seasons. For instance, this can cause long periods of glaciation. And for Earth as a system, it enters positive and negative climate feedback loops.

The effects are drastic for long-term climate change. And this is all because of Earth’s change in axial tilt that gradually shifts every 40,000 years.

3. Axial precession

Axial precession is the movement of the rotational axis of Earth. According to the Milankovitch Cycle, precession has a cycle of roughly 23,000.

Precession occurs because the Earth is not a perfect sphere. It flattens out at the poles and widens at the equator. In addition, the gravitational pull from the sun and moon causes precession.

Similar to obliquity, precession doesn’t change the total amount of solar radiation that hits Earth. But precession primarily alters the perihelion and aphelion.