If you are looking for ‘hockey sticks’ to match to, how about this an an alternative.
based on a comparison suggested by
So a change from rotational energy to heat? I can’t do the maths if any exist. Would be a possible explanation though. Cold = Fast, Warm = Slow. Spinning down towards entropy? Like a gaia ice-skater, pulling her arms in when she is cold and spreading them out when she is warm? Mass transfer between the Poles and the Equator. Over that long, slow, method of energy transport. Balanced finely on either side of a long slowdown throughout the ages to eternity. Too fast a decline and the world speeds back up towards the ‘middle’ as she picks up or looses energy above/below that ‘middle’. Overshoots because of the lags and it gets hotter or colder on the surface for a while. Then the steady decline resumes.
Think ‘old fashioned regulated steam engine’. Always chugging up and down on idle around a ‘middle’ speed set overall.
A shallow saw tooth pattern overlaid on a steady geometrical decline to entropy? Driven by orbital and mass distribution factors?
Now if we take that back to the Medieval Warm Period, is there a match there also? And further back still? The Roman Warm Period? The Ice ages? That would be a proof, surely.
Also it might explain why it is harder to find a wider global ~60-65 year signal in some data as we go backwards in time.
We can only make presumptions about the descent to the ‘bottom’ in UT1. The global patterns may differ on the downwards part of the cycle. Which would make the shorter cycle possibly only appear in the upwards part of the longer waveform.
Also possibly explain its presence in any case, as being part of the natural response, overshoot, undershoot, to the rising values.
Which causes which is the real question. And all well, well, well before CO2.
For the size of power available in momentum see
Where’s that missing heat now? I think it may be in cold, cold water at the bottom near the Equator.
Watery, icy hands to the poles. Watery, cold water hands to the bottom near the Equator.”