Milankovich Cycles
Number of papers: 9
Celestial Mechanics and Estimating the Termination of the Holocene Warm Period — Science of Climate Change, 2022; John Parmentola
Parmentola claims that the “precession index” largely determines temperatures on earth and projects that the next ice age in 20k years will be as deep/cold as the last one.
The Planetary Theory of Solar Activity Variability: A Review — Frontiers in Astronomy and Space Science, 2022; Scafetta & Bianchini
“Reviewing the many planetary harmonics and the orbital invariant inequalities that characterize the planetary motions of the solar system from the monthly to the millennial time scales, we show that they are not randomly distributed but clearly tend to cluster around some specific values that also match those of the main solar activity cycles. In some cases, planetary models have even been able to predict the time-phase of the solar oscillations including the Schwabe 11-year sunspot cycle.”
The inter-glacial cycle is not a 100,000-year cycle, it is a shorter cycle with missing beats — World Journal of Advanced Research and Reviews, 2022; Michael Oldfield Jonas
“The “100,000-year problem” refers to an apparent unexplained change in the frequency of inter-glacial periods which occurred about a million years ago. Before that, inter-glacial periods seemed to occur about every 41,000 years, in line with the obliquity Milankovich cycle. But after that, they seemed to occur about every 100,000 years, in line with the orbital inclination Milankovich cycle. Examination of the data shows that there never was a 41,000-year cycle, and that there is no 100,000-year cycle, but that the most influential cycle is the approx 21,000-year precession cycle which is the major factor in the cycles of insolation at higher latitudes.”
Asynchrony between Antarctic temperature and CO2 associated with obliquity over the past 720,000 years — Nature Communications, 2018; Uemura, et al.
You wonder how they decide between Nature Climate Change and Nature Communications? The papers that don’t support humans destroying the planet mostly get rejected, but a few manage to get into Communications. This one says their Antarctic ice-core temperature proxy “apparently leads CO2 variations. For example, during the last termination (TI), the start of Antarctic warming has been estimated to be synchronous with CO2 increase or to lead CO2 increases by 800 ± 600 years on the East Antarctic Plateau.” For most of the past 650,000 years, CO2 has lagged behind temperature by 300–1900 years.
West Antarctic ice volume variability paced by obliquity until 400,000 years ago — Nature Geoscience, 2022; Ohneiser et al.
According to these authors, obliquity — the 41,000 year cycle — seems to have determined the ice ages from 800k to 400k years ago, then eccentricity took over. Here’s a discussion of what may have happened 400k years ago. For more on this, see my Milankovitch blog post.
A simple rule to determine which insolation cycles lead to interglacials — Nature, 2017; Tzedakis et al.
As you can see from the papers above, there is disagreement in interpreting the various cores that tell us about ice ages. These authors developed a model that correctly predicts the glaciations of the last few million years. Is this the last word? No, but it’s progress.
Are insolation and sunspot activity the primary drives of Holocene glacier fluctuations?
This is a letter based on several peer-reviewed papers by Johannes Koch and John Clague (including future papers the two would write together) that shows convincing correlation between sunspots and glacial ice. This implies a solar irradiance cause for glacial growth and shrinkage and is another nail in the coffin of the CO2 theory. Remember, the IPCC doesn’t like to talk about the Holocene.
On the Cause of the Mid-Pleistocene Transition — Reviews of Geophysics, 2021; Berends et al.
“Over the course of over four decades of research, several different physical mechanisms have been proposed to explain the MPT, involving non-linear feedbacks between ice sheets and the global climate, the solid Earth, ocean circulation, and the carbon cycle. Here, we review these different mechanisms, comparing how each of them relates to the others, and to the currently available observational evidence. Based on this discussion, we identify the most important gaps in our current understanding of the MPT.”
Modulation of ice ages via precession and dust-albedo feedbacks — Geoscience Frontiers, 2016; Ralph Ellis and Michael Palmer
This paper considers an interesting hypothesis. There’s a brief summary by Friends of Science and Ralph presents his own work on Tom Nelson’s podcast. Ellis and Palmer claim that CO2 does not create ice ages, as many in the IPCC camp believe, and in fact it can’t, because CO2 is at its peak as ice ages are greatest (coldest) and CO2 goes down as the earth warms back up and ice recedes. Instead, they claim that low-CO2 conditions create dust, and the dust reduces the earth’s albedo, causing the ice sheets to retreat. The dust is easily discoverable in the Greenland ice cores. Is it true? Several people I trust say it’s a small part of the recovery phase. It may not be insignificant, but it may also not be critical.