Basil Copeland and Anthony Watts
I’m not ignoring you. I’m wrestling with the concept of how we would “prove” (or falsify) that the decadal or bidecadal cycles in global temperature are “caused” by ocean current cycles which are themselves likely driven by the same exogenous sources we’re attributing the temperature cycles to. For example, in the post I did on the PDO, I recall both a bidecadal and even a pentadecadal cycle in the PDO and NPI. Does that mean these are “causing” the cycles we’re seeing in global temperature? Or is it not more likely that these are just different manifestations of a common external (or exogenous) driver (or drivers)?
Or, suppose we could definitely link the decadal signal in global temperature trends to ENSO. So? What is driving ENSO? I’m sure we can cross-correlate cyclical variation global temperature with a variety of different climate variables. But you understand as well as I do that this doesn’t “prove” causation. It merely establishes association, possibly driven by common forces.
What are those common forces? Besides lunar and solar, what other candidates are there for the ultimate cause?
[My answer would be the lunar declinational tides being synchronized to the rotation of the magnetic poles of the sun.]