Rising CO2 levels supposedly ended last ice age, says study

While admitting that the Milankovich cycle was the real culprit.

Ice core records from Antarctica remind us of the Milankovich cycle. Photo credit: L. Augustin, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE)

A new record of past climate change supposedly provides compelling evidence that CO2 was the big driver of global warming at the end of the ice age.

“At the end of the last ice age, CO2 rose from about 180 parts per million (ppm) in the atmosphere to about 260; and today we’re at 392,” explained lead author Dr Jeremy Shakun in a BBC News interview. “Rising CO2 at the end of the ice age had a huge effect on global climate.”

Dr Shakun’s team constructed a narrative to explain the process:

  • This starts with a subtle change in the Earth’s orbit around the Sun known as a Milankovitch “wobble”, which increases the amount of light reaching northern latitudes and triggers the collapse of the hemisphere’s great ice sheets
  • This in turn produces vast amounts of fresh water that enter the North Atlantic to upset ocean circulation
  • Heat at the equator that would normally be distributed northwards then backs up, raising temperatures in the Southern Hemisphere
  • This initiates further changes to atmospheric and ocean circulation, resulting in the Southern Ocean releasing CO2 from its waters
  • The rise in CO2 sets in train a global rise in temperature that pulls the whole Earth out of its glaciated state. (“If you believe this last point, you are ready to believe anything,” says analytical chemist Hans Schreuder.)

So let’s look at this. What happened first?

First, came the Milankovitch “wobble.”  Then came the rise in CO2.

Saying that the rise in CO2 drove the earth out of the ice age is like saying that someone riding on the roof of a bus is driving the bus.

The end of the last ice age was not triggered by rising CO2 levels, it was triggered by the Milankovich cycle. It  nothing to do with humans back then, and it has nothing to do with humans now.

The Milankovich cycle is caused by a natural process known as precession of the equinoxes.

Here’s how I describe equinoctial precession in Not by Fire but by Ice. (p. 169-170)

Equinoctial precession –  Pacemaker of the ice ages

(The earth’s) axis of rotation wobbles like a top, tracing a clockwise circle around true north. Called axial precession, it takes about 25,800 years to make the full circle. Precession occurs, say scientists, because the sun and moon exert a gravitational pull on the earth’s equatorial bulge. Rotating objects such as tops and gyroscopes also precess. So does Mars.

To understand this phenomenon, picture the globe spinning around a long stick (the axis of rotation). Tilted away from true north, the top of the stick traces a circle around the North Pole, while the bottom makes an identical trip around Antarctica.

As our axis of rotation moves, it constantly points toward a different star. If the stick were longer, it would paint an imaginary circle on the heavens. The process of painting that circle on the celestial ceiling is called precession of the equinoxes.

Precession of the Equinoxes - Copyright Robert W Felix


This is not a new theory. The Greek philosopher/scientist Hipparchus first discovered precession of the equinoxes in the second century B.C. when he compared his own astronomical measurements to those made by Timocharis some 150 years earlier. But he mistakenly concluded that the stars were moving in a circle through the sky.

Eighteen centuries later, Sir Isaac Newton solved the rest of the riddle. Our orbit around the sun also revolves, said Newton. The orbit itself revolves backwards, or counterclockwise. Precession of the equinoxes, the time it takes to paint that imaginary circle on the heavens, therefore takes about 23,000 years. It’s like waiting for someone on a merry-go-round. You’ll reach them sooner if you walk toward them.

This is deadly important. The equinoctial precession cycle is a killer . . . and it’s about to strike again.

Today when viewed from the northern hemisphere, the stars seem to rotate around Polaris at the end of the handle of the Little Dipper. That’s why it’s called the Pole Star; because the North Pole points toward it. But in 2,000 B.C. the North Pole pointed toward a spot halfway between the Little Dipper and the Big Dipper. In 4,000 B.C. it pointed toward the end of the handle of the Big Dipper. Twelve thousand years from now it will point toward a different star, toward Vega, and in 23,000 years it will point toward Polaris again.

Forget your CO2.

Equinoctial precession is the real pacemaker of the ice ages . . . and it is about to lead us into the next ice age.

See entire BBC article:
Thanks to Hans Schreuder and Winona  Campbell for this link



17 thoughts on “Rising CO2 levels supposedly ended last ice age, says study”

  1. During the precession of the equinoxes does the earth actually move any further away or closer to the sun??? Unless the earth actually moves closer or further away from the sun, how does the earth experience more sunlight exposure???

    • Precession describes the Earth’s tilt as swinging like a pendulum. At maximum tilt, more areas(latitudinally) of the Earth’s surface are exposed to Solar influx. At times of least tilt the poles get colder, and the equatorial zones experience more aridity. One reason that Ice ages see an increase of desertification.

      Annually the Earth moves closer(currently N. Hemi. Winter) and farther(currently N. Hemi. Summer) from the Sun. This is because the orbit is elliptical, and there are probably a few other factors (Jupiter, Saturn, etc.) that influence this. This too would change over long time periods.

    • Technically, the earth does not move, but the tilt angle does, so that land areas during the precession receive more or less direct sunlight depending on where we are in the precession. We are currently at a point in the precession where earth was at the beginning of last ice age. Tilt angle known as precession of the equinoxes rules as the main climate driver.

    • As I understand it, it has to do with whether the northern hemisphere experiences winter during perihelion or aphelion. Currently, the north is in winter during perihelion, which slightly moderates the seasons.

  2. “Says flawed study…” – they want it both ways. It is certain that CO2 follows temperature change, and does not lead it. So it is perfectly normal for atmospheric CO2 to rise due to an increase of global temperatures.
    I am again reminded of the open can of soda pop in the fridge(cold) retaining it’s fizz longer than an open can on the kitchen counter(warm). The Oceans work in the same way. One thing that these Carbon Dioxide blamers seem to miss entirely is the CO2 injected into the oceans by deep sea volcanism. Polar waters will tend to hold more CO2, while Tropical waters will fizz out and provide the gas necessary for photosynthesis in the equatorial ecosystems.

  3. I believe that levels of CO2 in the atmoshere have absolutely no effect on the climate. It is my opinion that what is really behind climate changes, warming or cooling, is fluctuation in the amount of COSMIC RAY INDUCTION, bringing on ups and downs in the amount of volcanic activity. Although it is not the present day fashion to do so, nevertheless for entirely scientific reasons, I hold to the HOLLOW EARTH THEORY. Often people do not want to believe that stars and planets are hollow because they cannot understand where volcanic activity is coming from. In their mind if the Earth is hollow then where is the volcanic activity coming from they ask. Well in my opinion the crust of the hollow Earth is no more than 50 kilometers thick. That crust is being hotted up by COSMIC RAY INDUCTION, which is also the driving force for gravity and magnetism too. I see volcanic activity as being a typical electronic phenomenon. Static charge building up in the crust, which then sporadically releases the accumulated energy as the charge over comes the natural electronic resistence of the crust, thus bang, volcanic activity. Thus in my understanding there is no such a thing as a dead volcano. Extinct volcano’s do not exist. I am told that every planet in our solar system has been getting warmer over the past decade. How can we explain this ? Only if we accept that global warming is as a consequence of the increase in the amount of Cosmic Ray energy penetrating the solar system. Increasing because of the collapse of the heliospheric bubble, brought on by fewer sun spots. So that the temperature variations found in the Greenland Ice Cores is probably a very good record of Cosmic Ray fluctuations too. In my opinion the existence of plate tectonics is very clear proof that the Earth is obviously hollow. Also crustal displacement, as proposed by Albert Einstein and Professor Hapgood, is therefore even more likely than ever they thought it to be.

  4. What plant eating and oxygen breathing humans should be concerned about regarding the atmospheric CO2 is that the optimum level for plant growth is between 800 and 1,000 ppm, and at the present 390 ppm, the plants are malnourished. Reduce CO2 levels further and plants suffer, and at 220 ppm growth slows, and at 150,it stops.

    Regarding water, as CO2 levels rise, the stomata [pores]of the leaf partly close – thus moisture loss via transpiration is reduced. This gives an indication on the environment that the vegetation has evolved. And, most plants grow at 2-3 times faster at 1,200 – 1,500ppm. Such fast growth was required to feed the large plant eating dinosaurs.

    As went the dinosaurs, so goes humans.

    • Maybe so, but increasing the CO2 is like fertilizing a dead plant. Many plants cannot handle an increase in temps. We are seeing more and more plant species migrate towards the poles as the temperature changes, and this is with the very slight upward trend. As the globe continues to warm, many of these will die. As plants die, ecosystems will be disrupted, effecting animals as well. Don’t forget about farmers’ crops that need specific temperatures to thrive. The difference between now and the last ice age is 2 degrees Celsius. now image that we go the opposite way.

  5. So I take it this was a man caused CO2 increase 12,000 years ago? You can’t have it both ways!

  6. Somewhere along the way the contribution by Henrik Svensmark will likely be integrated into this Milankovitch cycle thing. I understand that our solar system doesn’t just rotate around the galaxy over 250 million years or so, but also bobs below and then above the galactic plane in a regular pattern. So the cosmic rays would likely hit our atmosphere in a changing fashion in regard to the orientation of Earth within the heliosphere and the orientation of the solar system to the galaxy. It’s beyond me. I look at it in a pragmatic fashion. If Professor Vladimir Paar and Dr. Abdussamatov both say climate is about to go cold, around 2014,one saying it is a Little Ice Age, the other saying it is our interglacial period ending and glaciation of 70,000 years starting, because it fits the repeating pattern, the solar cycles involved that they study differing, and then I take a look at the graph for our last 10,000 years, knowing that’s how long the interglacial is supposed to last, and the curve of it just shrieks of glaciation cycle onset. Volcanic activity has seemed to increase. We now know how powerful some extra cosmic rays can be in bringing on the solar reflectivity to cool the Earth, we know the prediction is for a 200 year solar magnetic cycle, for the shield to be very weak. However it is that the mechanisms and their relationships may work out in the details one day, it seems to be something that works as a system with one part facilitating the other and accelerating the shift to a cold climate in a multi pronged attack of volcanic ash, SO2, and denser more reflective clouds. The Irish pond mud studies, the Vostok ice core studies tell us the shift in conditions to bring on glaciation can take a year or less. I think we are seeing the start of the real thing, not just a Little Ice Age. I expect that we won’t live to see the end of it even if it is a Little Ice Age. I am hugely disappointed in our political “leaders” and our Presstitutes who are either turning a blind eye or are so stupid they really cannot see it yet. Humanity will adapt but it looks like individuals and perhaps religious groups will have to take it upon themselves. I think people have already died from the end of the warming. People are on their own really.

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