By Kirby Schlaht

Is paleoclimate cyclic?

Does the climate model below (Fig 6) represent a real climate cycle that actually repeats every 675 million years? If so, might the galactic spiral structure with its accompanying cosmic radiation be responsible? Is the spiral structure of the Milky Way “stable”, such that we will encounter the same spiral arms and inter-arm regions over and over as we orbit the gravitational center of the galaxy?

The Story of Climate Change is based on the concept of atmospheric ionization by high energy cosmic rays initiating aerosol and cloud formation. This results in a warming or cooling planet Earth. This cloud albedo effect (Svensmark) is the first leg upon which The Story of Climate Change rests (https://thestoryofclimatechange.substack.com). Galactic cosmic rays, mostly high energy protons, play the central role in this process by ionizing atmospheric gases as they descend into the lower troposphere. Radio observations of exo-galaxies indicate that cosmic rays are galactic plane polarized and are confined to spiral arm structures. This means that during our solar system’s transit through the Milky Way spiral arms the cosmic ray flux will be modulated. High flux levels during spiral arm crossings result in cloudy and cooling climates while lower flux during inter-arm space crossings results in less cloudy and warming climates. These we can call geologic Ice House and Hot House epochs. Our planetary system’s galactic orbit is circular but oscillates in and out of plane manifesting a secondary high frequency cosmic ray flux modulation. This results in a periodic 30-million-year warming-then-cooling cycle (Veizer, Shaviv). These superimposed drivers can be visualized in my 675-million-year climate cycle based on a one-billion-year splice of Veizer and Halverson isotope proxies (part 1, https://thestoryofclimatechange.substack.com/p/the-story-of-climate-change-part-0fd ).

What does this mean?

As our solar system continues to orbit the galactic center, we appear to encounter the same spiral arms and inter-arm regions again and again. If this process influences the climate, the cyclic nature of paleoclimate should be revealed. Assuming that the nearly 13-billion-year-old Milky Way galaxy structure has been stable in aggregate, at least since our system’s inception – about 5 billion years, we will continue to repeat the same pattern and periodicity of climatological conditions into the far future. The spiral arms of the Milky Way appear to us to be rotating but at a slightly different speed than other stars in the disk like our sun. From the solar perspective we appear to be at rest while the galactic structure moves past us and slowly recedes in our wake. It has been estimated that our system orbits the galactic center every 225 million years or so. Our story indicates that three of our galactic orbits will result in one complete spiral structure transit – every 675 million years.

How can this pattern of stars, dust, gas, and energy persist if the objects in the galaxy are moving along their unique orbital paths with their unique orbital periods? Is this “spiral” an illusion or does the phenomenon have a physical explanation? Why are the cosmic rays mostly in the spiral arm structures and absent from the inter-arm regions? Do the spiral arms actually exist discretely as rotating standing gravitational waves or are they a function of rotating density waves propagating through the galactic disk of stars ever renewing their inventory of arm stellar masses? It is a mystery to me and the second leg upon which The Story of Climate Change rests. We do however, live in a metaphorical world. We do many things and think many thoughts because we believe that a carbon dioxide climate driver narrative is true. We can play at that game too. Shall we proceed as if The Story of Climate Change were also true? Beautiful stories may not be wholly true but they can inspire us to venture beyond the mundane – now that’s when the real fun begins.

Let’s imagine …

Let’s imagine the near future, say, 10 to 20 thousand years hence. I think we might assume that humanity will still be the dominant species on the planet as it has been since our exodus from mother Africa about 70 thousand years ago. Shall we consider the future climate landscape if anthropogenic carbon dioxide forces the Earth into a new Hot House environment 5 to 10 degrees Celsius warmer than today? Would you imagine that our climate in 10 thousand years would resemble the Hot House Cretaceous Period of around 75 million years ago? The climate of the dinosaurs. Would we see no polar ice caps, sea levels 300 to 600 feet higher than today, CO2 levels as high as 2000 parts per million – 5 times higher than today, and forests on Antarctica? If we did enter a Hot House how long would it last? Would the Hot House end on its own – if so, why would the temperatures fall? The pattern and periodicity of real paleoclimate change however, do not seem to be well explained by weathering, subduction, and volcanic activity cycles throughout Earth’s geologic past

Of course we would not be forced into a new Hot House. Remember, a Hot House is manifested by inter-arm space crossing during our galactic orbit. Our planet will remain within the cold Sagittarius spiral arm for another 120 million years or so – driving cloudier and cooler climates. We will linger near in-plane within this arm for another 2 to 3 million years driving cloudy and cool climates. The Milankovitch planetary orbital cycles can then show their influence by driving the climate to oscillate between cold glacial expansion and warm inter-glacial periods. 

Where are we now? First, we are fully in-plane with the Milky Way and experiencing maximum cosmic radiation with maximum propensity for aerosol and cloud formation. We have been in the Pleistocene Ice Age for about 3 million years. We are in the middle of this most recent 20-thousand-year interglacial period. In 10 thousand years, a mere 300 generations, we will be at lowest planetary obliquity and sliding into the next 80-thousand-year period of glacial expansion. Just a few hundred years after glacial inception the higher latitudes would be uninhabitable with the massive expansion of sea ice onto the continents as glaciers. As the ice expands it makes the albedo of our planet more reflective – returning more sunlight back to space and cooling things off even more. This is ice albedo feedback in action. A runaway Ice albedo process is thought to explain the Snowball Earth scenario 640 million years ago during the Cryogenian period. In 600 generations, 20 thousand years from now, we will be in the cold depths of the expanding ice age. About 1 hundred thousand years the Milankovitch cycles will find a resonance when both obliquity and eccentricity move higher providing more insolation to the higher latitudes. This breaks the ice albedo feedback loop, reversing ice expansion and initiating the next warm interglacial period.

Over the next 3 million years, as the out-of-plane orbital motion of our planetary system reduces cosmic radiation, cloud cover will be reduced driving temperatures warmer. This Pleistocene Ice Age will finally dissipate, leaving behind these glacial-interglacial oscillations – for now. What goes up must come down. In about 15 million years we will reach maximum out-of-plane position with the accompanying warmest temperatures. Our star system once again proceeds back into the galactic plane cooling the planet. 30 million years from now, while crossing deeper into the Sagittarius spiral arm, we will once again be fully in-plane receiving the highest cosmic ray flux, resulting in more ionization, and maximum propensity for cooling cloudiness and glaciers returning. This will mark the entry into the next Ice Age. Since our climate is cyclic, the past climates will be repeated – with a replay of the Marinoan Ice Age of 640 million years ago.

The big wheel keeps on turning

In about 120 million years we will finally cross the Sagittarius spiral arm. We will exit this Ice House with its periodic glacial ages and enter the next Hot House inter-arm space on our way into the next spiral arm region – the Perseus arm. Round and round we go.

With this knowledge and climate foresight of a cooling, icier world what should we do? It is hard to imagine, but we could organize this super organism we call humanity and implement a plan for adapting to the coming cold snap. Albedo modification, space-based solar mirrors driving back the continental and sea ice termini, and CO2 emission expansion might not be powerful enough climate weapons to fight mother nature.  But, maybe by then, the climate alarmists would be warning us about the real problem. Humans are notoriously short sighted though – much like the proverbial frog in a slowly freezing pond – before we even realize it, the brutal physics of cold finally catches up with us.