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Discussion > Where do the denizens of BH think our climate is going?

Posted in Climate News Roundup|Tagged Science & Environmental Policy Project|12 Comments

Onset of the Next Glaciation

Posted on September 16, 2012 by Anthony Watts

Guest post by David Archibald

This was the title of a WUWT thread yesterday and it was commented on here at BH. Some people complained that it was based on a model, others agreed with the thrust of the thread and one posted a reference to a paper by Gerard Roe on Milankovitch Cycles which were the basis for the model's predictions.
I followed the link to the paper by Roe and then realised I had been there before, this paper was recommended by Doug Keenan at the Guardian debate a couple of years ago.
The basis of both the WUWT thread and the paper by Roe was the belief that Insolation was the trigger for the end of the last glaciation. Roe differed from the WUWT thread in that he believed it was the rate of change of insolation not the "absolute" insolation that was important. Insolation is the currently accepted cause of the change from glaciation to interglacial and back again.
Well I disagree ^.^
Obviously not because of anything I personally have discovered hehe.
Regular posters here will know that I am a follower of Henrik Svensmark and his theory that climate is controlled by cosmic rays in conjunction with the sun's cycles.
When the intensity of cosmic rays entering our atmosphere increases then large molecules are formed which seed low clouds, albedo increases and we cool.
Well in relation to the WUWT story an atomic physicist called Gerald E. Marsh published a paper entitled "INTERGLACIALS, MILANKOVITCH CYCLES, AND CARBON DIOXIDE" I dont know when and I dont have a link, I just have a PDF so sorry about that.
Marsh was a one time adviser to the US government on nuclear weapons and also had a letter published in the FT about the UK replacement options for Trident. Marsh is currently at the University of Chicago.
His paper seems to be a synopsis of other papers plus his own calculations. An important part of his conclusions relate to another paper by Kirkby et al 2004. Kirkby et al shows that the warming at the end of the last glaciation was already underway at the insolation minimum and that the warming was complete 8,000 years before the insolation maximum.
What Marsh pointed out was that changes in the Cosmic Ray Flux appeared to be the cause of the initial warming, the lower the intensity of the CRF the less low clouds and lower albido.
If Marsh and Svensmark are right then it may be that we do not return to glaciation for a very long time.
The prediction is that a solar minimum in cycle 25 or some time over the next 50,000 years could take is back to glaciation. However Svensmark tells us that we (the Sun) are currently leaving the spiral arm which we have been crossing for some time (cant be bothered looking up how long cos its late). As the Sun leaves the spiral arm it is moving from an area of dense CRF to an area of minimum CRF. The Sun's solar cycles are only important if there is a strong CRF to deflect, if the CRF is itself insignificant then solar cycles will become irrelevant.
As we cross a large area of few stars and low CRF I think we will enter a long period of much warmer temperatures than today.

Sep 17, 2012 at 11:30 PM | Registered CommenterDung

Why do you assume that CRF is determined by galactic position, do we know if cosmic ray density (for want do a better word) increases or decreases in the spiral arm. I'm not criticising, just asking.

Sep 26, 2012 at 12:10 AM | Unregistered CommenterMarkington


Svensmark tells us that we (the Sun) are currently leaving the spiral arm which we have been crossing for some time (cant be bothered looking up how long cos its late). As the Sun leaves the spiral arm...

Leaving the solar arm? In what sort of timescale? Do you have any idea how big the galaxy is, how fast the stars in the arm are travelling or how long it might take for our position in the arm to change significantly? I think you will find it is a LOT longer than anything on a human species timescale.

Sep 26, 2012 at 11:15 AM | Unregistered CommenterBitBucket


Cosmic Rays originate from Super Novae (Novas? hehe) or collapsing stars, the bulk of stars exist in the spiral arms and the core. When we move into the space between the arms the density of Cosmic Rays is less.

Sep 26, 2012 at 7:28 PM | Registered CommenterDung
Indeed so, I was about to post this when the battery died.
Interesting times ahead.

Sep 26, 2012 at 11:41 PM | Unregistered CommenterMarkington

The Sun is a variable star, especially in the Extreme Ultra Violet.

The Earth orbits in the Sun's turbulent atmosphere/magnetosphere, making one revolution every 365.25 days.

The Sun orbits the Milky Way galaxy approximately once every 225 million years.

The Milky Way galaxy is in the process of colliding with the Andromeda galaxy. The actual collision will occur in about 4.5 billion years.

With our little planet passing through all this variable space weather we are asked to believe that…

A 0.04% concentration of the trace gas carbon dioxide in the Earth's atmosphere is the most important driver of planetary temperature?

Gimme a break!

To answer the question, "Where do the denizens of BH think our climate is going?" - I'm absolutely certain the climate is going to change.

Sep 29, 2012 at 1:08 PM | Unregistered CommenterScottie


It sounds like the Met Office cheated when they asked for a new super computer if they knew they were only going to have to forecast climate for another 4.5 billion years -.-

Sep 29, 2012 at 3:06 PM | Registered CommenterDung


No, it's not quite as bad as that. They only have to peer 1.4 billion years into the future!

According to Wiki:

"…by the time that the two galaxies collide, the surface of the Earth will have already become far too hot for liquid water to exist, ending all terrestrial life, which is currently estimated to occur in about 1.4 billion years due to gradually increasing luminosity of the Sun."

But my point is still a serious one. With so much other stuff going on as the Earth hurtles on a wobbly orbit through (far from empty) space, the CO2 hypothesis tests one's credulity to the limit.

Sep 29, 2012 at 3:42 PM | Unregistered CommenterScottie


You are preaching to the converted mate :)
I suppose a lot will happen in 1.5 billion years but I do wish humanity would embrace the idea that if we wish to survive as a species then we need to exist on more than one planet. From what you say that should be in more than one galaxy.

Sep 29, 2012 at 9:46 PM | Registered CommenterDung

Scottie's posts are very relevant to claims that man will soon exhaust the resources we need to survive and feed ourselves (UN Agenda 21).
According to Scottie human life on Earth has a known end point at about 1.4 billion years from now or sooner.
Robert Zubrin (atomic physicist and author of "The Merchants of Despair") reckons that there is enough Thorium to generate power for 8 billion years. We therefore need to make every effort to use resources more quickly or we will end up losing them! hehe

Sep 30, 2012 at 2:25 PM | Registered CommenterDung