Understanding what causes the superimposed natural 60-year climate cycle.

If you look closely at the red moving average global mean temperature lines on the monthly graphs at drroyspencer.com you will detect steep rises prior to 1998 which was close to the peak in a natural cycle taking just under 60 years.  This cycle is superimposed on a longer cycle that had peaks in the Roman Warming Period and the Medieval Warming Period and which will peak again before the end of this century, followed by about 500 years of cooling.  Now the longer cycle is still rising but the 60-year one is falling.  So, we saw only 0.1 degree of net warming between the peak in 1998 and November 2023.

If we ask what process could be regulating these cycles (as I did back in 2011) we would probably suspect that it must have something to do with planetary orbits.  Even back then I could see that the 60-year cycle appeared to relate to the fact that Jupiter and Saturn (two large planets) align every 60 years.  Jupiter's orbit takes 11.86 Earth years and Saturn's takes 29.46 Earth years.  Think of that as 12 and 30 years then the lowest common denominator is 60.  Later I became fascinated by this graph which is based on the inverted scalar sum of the angular momentum of the Sun and all planets.  The longer cycle could have something to do with the eccentricity of Jupiter.

"Why is it so?" would Prof Julius Sumner-Miller (whose lectures I attended) have asked.  There is now a well-proven correlation between cloud cover and cosmic ray intensity (as seen here) and it is not hard to understand the link between such cloud cover and surface temperatures.  Also see this article.  The fields of planets can bend the paths of cosmic rays and so, when two large planets have a combined pulling effect (because they are in alignment) we can see a reason for the 60-year cycle as more rays are directed away from or towards Earth. 

What about the longer cycle?  For some reason there appears to be a similar long-term cycle in sunspot activity which was at a minimum in the Little Ice Age.  Perhaps Jupiter's eccentricity has something to do with it.  Whatever the reason, it is well known that the size of the heliosphere increases with sunspot levels and this sphere (extending beyond Earth's orbit) acts as a partial shield to cosmic rays.  So, this is why I say, "Cosmic rays cause climate change, not carbon dioxide."  My main papers refuting the radiative forcing greenhouse conjecture are here.