Restoration of a group in late Pleistocene northern Spain, by Mauricio Antón

Why do Ice Ages occur? A New Paradigm Shift on a Prehistoric Problem


Why do ice ages occur?  Surprisingly, even after many decades of paleoclimatic research we simply do not know for sure. Most scientists will agree that ice age cycles have something to do with precession: the slow wobble of the axis of the Earth.

The ancient Egyptians and Greeks knew of precession and called it the Great Year, because it gives warm and cool seasons over its approximate 23,000-year cycle. But there is a problem with invoking the Great Year as the regulator of ice ages, because we should really get an interglacial warming every 23,000 years or so. And we don't—they only happen every fourth or fifth Great Year.

Warming and Cooling

But why should the global climate give a selective response to orbital warming and cooling (called 'forcing' in the climate trade)? This is one of the great unknowns of modern science. Many suggestions have been made, from interstellar dust blocking sunlight to the weight of the ice sheets depressing the lithosphere and warming the ice. And yet all of these theories share one thing in common: they stretch credulity.

The Athabasca Glacier is one of a handful that makes up the Columbia Icefield in Jasper, Alberta, Canada. An Ice Age relic, the ice is 10,000 to 15,000 years old.

The Athabasca Glacier is one of a handful that makes up the Columbia Icefield in Jasper, Alberta, Canada. An Ice Age relic, the ice is 10,000 to 15,000 years old. (CC BY-NC-SA 2.0)

The only thing that is certain, is that the science is not settled in this area of ancient climate research.

The Perennial Conundrum of Paleoclimatology

But a new theory by independent researcher Ralph Ellis may have unlocked this perennial conundrum of paleoclimatology. And considering the myriad implications that flow from this theory, its mechanism is nevertheless very simple to understand.

What we need is a selective feedback system that can act either in concert with, or in opposition to, the warming and cooling provided by the ~23,000-year Great Year. At present it is claimed that this feedback agent is CO2, because CO2 is a warming agent and its concentrations do indeed rise and fall with the ice ages.

But there is a big problem with this assertion, because when CO2 concentrations reach a minimum in the depths of the ice age, the world warms. And when CO2 concentrations reach a maximum during the warm interglacial period, the world cools. And yet this is the very opposite of what should happen if CO2 was the most powerful warming feedback agent.

Artist’s depiction of Ice Age on Earth

Artist’s depiction of Ice Age on Earth (CC BY-SA 4.0)

The Achilles Heel of Albedo

This is where the new theory by Ralph Ellis shifts the paradigm, and the primary character in this new climatic drama is albedo - the reflectivity of the Earth.

Obviously polar ice sheets are highly reflective, they have a high albedo, and reflect up to 90 percent of the incident sunlight during the all-important northern summer. This allows the polar ice sheets to slowly grow, year after year, and slowly reflect more and more incident sunlight in the process. And this ice-albedo reflection mechanism is so strong, it can even resist the next Great Summer when northern sunlight is once again at a maximum, which is why some Great Summers produce no global warming whatsoever.

A graph of sunlight strength at 65ºN (blue) vs Antarctic temperatures (red). Each red peak represents an interglacial warming, which occur roughly every 100,000 years. The blue peaks represent Great Summers in the northern hemisphere. Note that not every Great Summer produces an interglacial global warming.  (Sources:  Laskar 2004 orbital cycles,  Epica3 2007 temperature data.)

But if albedo is so strong that it can shrug off the increased sunlight of a Great Summer, then how does the climate system generate an interglacial warming? The answer is that ice-sheet albedo has a very prominent Achilles heel: dust.

If dust gets on ice sheets their albedo is reduced considerably and they can melt very quickly. And surprising as it may seem this is exactly what happens, because every interglacial warming period is preceded by about 10,000 years of intense dust storms. And we know that this dust settles on polar ice-sheets, because the ice-core data still contains that dust. And in the Greenland ice-sheet, the majority of that dust appears to have originated from the Gobi Desert. But rather than being a shifting-sand desert, most of the Gobi is currently pastoral steppe grasslands, where the herds of the Mongolian nomads graze. So how and why does this large steppe plateau become a true sand desert?

It has been claimed that desertification at the ice age maximum was caused by a cooling and drying of the climate. But there are many strands of evidence that conflict with this argument, and point towards a cooling of just 3ºc in tropical and extra-tropical regions, combined with only a slight reduction in precipitation.

The answer to this problem is CO2 concentrations, which reduced during the ice ages as the seas cooled and absorbed more atmospheric CO2. They eventually reached as low as 190 ppm, which is dangerously low for much of the world's plant-life. Most plants suffer severe stress at 190 ppm CO2 and die at 150 ppm, because CO2 is a primary plant-food. And the fact that vegetation was suffering from CO2 starvation during the depths of the ice age was confirmed recently by a study of ancient trees preserved in the La Brea tar pits in southern California.

Great Summer and Great Winter

And now we have the entire ice age forcing and feedback mechanism, laid out and plain for all to see. It begins when a Great Summer turns into a Great Winter, which reduces the sun-strength in the northern hemisphere and allows ice sheets to grow. This is a slow process that takes tens of thousands of years, and appears destined to turn the world into a complete snowball.

Let’s hope this isn’t the case anytime soon. Artist’s depiction of modern Ice Age.

Let’s hope this isn’t the case anytime soon. Artist’s depiction of modern Ice Age. (CC BY-NC 2.0)

However, the Achilles heel of the high albedo polar ice sheets come into play— the dust. As the ice sheets grow and the seas cool, CO2 also reduces. The concentration finally reaches the critical 190 ppm level where world flora begins to die, especially at higher altitude, and the Gobi steppe-lands turn into a true sand desert. This turns northern China into the equivalent of 1930s Dust Bowl America, and the ensuing dust storms dump thousands of tons of dust onto the northern ice sheets each year.

A dust storm approaches Stratford, Texas, in 1935.

A dust storm approaches Stratford, Texas, in 1935. (Public Domain)

And so when the next Great Summer comes along, the dusty polar ice sheets can warm and melt and the next interglacial is born. So CO2 can indeed cause global warming, but its effect is much more pronounced at low rather than high concentrations.

A summary graph of all the factors that play a role in glacial modulation.

A summary graph of all the factors that play a role in glacial modulation.

Ice sheet extent (light blue) grows, forcing the temperature to fall (red). And CO2 concentrations (yellow) fall alongside temperatures, as CO2 is absorbed by the cooler oceans. When CO2 concentrations reach a minimum of 190 ppm there is desertification and large dust storms (purple). And when the next Great Summer comes along (blue sine wave), the dusty-ice sheets can melt and the world warms into another interglacial (red peak).   (Sources:  Laskar 2004  orbital cycles,  Epica3 2007 temperature data)

© Ralph Ellis, Sept 2015

Featured image: Restoration of a group in late Pleistocene northern Spain, by Mauricio Antón (CC BY 2.5)

By Ralph Ellis

References

Ralph Ellis, 2016. “Modulation of Ice Ages via Precession and Dust-Albedo Feedbacks”. Academia.edu [Online] Available at: https://www.academia.edu/20051643/Modulation_of_Ice_Ages_via_Precession_and_Dust-Albedo_Feedbacks

PMIP  (2015) “Paleoclimate Modeling Intercomparison Project (PMIP)” [Online] Available at: http://pmip3.lsce.ipsl.fr/

The average of eleven precipitation models: http://pmip3.lsce.ipsl.fr/share/database/maps/lgm/pr_ann_piControl_diff_lgm_AverageModel.png

The average of eleven temperature models: http://pmip3.lsce.ipsl.fr/share/database/maps/lgm/tas_ann_piControl_diff_lgm_AverageModel.png

Ward, J.  et al  (2004) “Carbon starvation in glacial trees recovered from the La Brea tar pits in southern California.” [Online] Available at: http://www.pnas.org/content/102/3/690.full    doi: 10.1073/pnas.0408315102

Laskar, J.  Joutel, F.  Boudin, F.  et al  (2004) “The Institut de mecanique celeste et de calcul des ephemerides.” [Online] Available at: http://vo.imcce.fr/insola/earth/online/earth/online/index.php

Epica3 data  (2007, 2008, 2015):

For Epica3 dating methodology please see:

Parrenin, F.  Barnola, J. Beer, J. Blunier, T.  Castellano, E.  Chappellaz, J.  Dreyfus, G.  Fischer, H. Fujita, S., 2007. “The EDC3 chronology for the Epica Dome C ice core”. Clim-Past.net [Online] Available at: http://www.clim-past.net/3/485/2007/cp-3-485-2007.pdf

Comments

Planet X!
The entire government are evil treasonous criminals. The day of the next false flag using the nuke they stole in 2007 and blamed on Iran, America will be destroyed by Russia, China and the SCO. This is the war of Armageddon and you can know it is now because of Planet X and the toxic chemtrails that hide it every day. Planet X will end the war when it rips the earth apart again but 90% of Americans will be dead already. All planned by your evil government.

My current understanding is precession at nearly 26,000 years (25,920 +-),
this author is at 23000 years. Milankovtich (1920's) wrote extensively on all the forces that influence this planet over long cycles of time, this planet is a temperate planet and very much an ice planet over millions of years. We live in the sweet spot era. We should take care of the time we have here.
Mother Earth has shaken off many other species and civilizations from its back.

I have no problem with the theory of ice being here in North America. I have a problem with so called glaciers that were here. As every one knows, what moves a glacier is gravity and glaciers are pulled down hill. But many claim that glaciers went up hill, some many thousands of feet up hill. This is a really big lie as there is no glacier on earth that goes up hill. They don't tell you that there are two things that can make glacial formations. One of course is a glacier the other is moving water and moving water can go up hill. They used to say tell a lie three times and it will become truth, but some of us still know its a lie.

What ice ages?  The idea that the Earth had ice ages remains only a theory, not a fact.  

None of the theories about ice ages has posited a mechanism that would work.  All of them say that ice formed by precipitation, but that cannot have happened, because of physics.  

Everything we have learned about cosmology and the history of the Earth amounts to a gigantic lie followed by massive errors built on the first lie.

We live on a flat earth confined by a dome.  The entire idea that we live on a globe surrounded by an infinite vacuum flies in the face of the most basic science.

Under the second law of thermodynamics, the vacuum of space would suck the air and water off the Earth in a millisecond.  Tons of other simple, every day physicla laws make a ball earth impossible.  An infinite vacuum of space would rip any space craft apart in a millisecond.  It would tear humans apart quicker.

The globe has become a deeply ingrained religious belief among almost all modern humans.  It flies in the face of all sicence, all logic, and all human experience, but everyone believes it.

Do you feel the Earth moving under your feet at 1000 mph?  Do planes flying from NYC to LA take the same time as planes flying from LA to NYC?  

Planes could not fly from NYC to LA under the current model, with the Earth spinning at 1000 mph east to west.  

Orbital mechanics cannot work.  Newton knew nothing about it and Einstein ignored it, if he knew anything about it.  If in fact we live in a soalr system with the Sun orbiting the galaxy at 500,000 mph, the planets and moons would crash into each other like bumper cars driven by drunk parents at the county fair.  Planets would have to constantly decelerate and accelerate as they orbit.

Tom Carberry

Colin Berry's picture

Silly me, for not realizing that Silbury Hill (see my recent posting) was your Mother Dome  ;-)  That's where the newly deceased – or one or more vital organs thereof - were interred to have the Earth Mother (and captive wormery) release the soul from mortal remains.

Somehow, one suspects that boring old science would whittle that down to mortal remains and earthworms, so we mustn't expect Silbury Hill to lift off anytime soon.

ColinB

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