I find it interesting: in my field (Mediterranean archaeology) there is some evidence that we get a weather Event every 500 years, and 2000 would have been one of those years. Understand, when you’re talking about such things, the edges are blurry, but these Events tend to involve drought in the Steppes and Tarim Basin, etc. Some have suggested the Sun might have a periodicity: the flux is too short-term to be the Sun passing through waves in the galactic disk (another suggestion for ice age variations)…but just kind of over all interesting whether we have more or fewer sunspots inside the Event parameters, but the Tarim, I believe, has been in a dry bit. Tarim
How do Mediterranean archaeologists notice this? Every 500 years some new band or plague comes riding out of the Tarim to annoy nascent civilizations. And it holds up pretty well over time.
There are other cycles, e.g. “the precession of the equinoxes”, nutation, etc. But the precession in particular is 26,000 years. We all know about the 11-year sunspot cycle, of course. 500years is a new one to me.
I sort of presume by “Tarim” you mean east-central Asia. There’s something of a recognition now that the cyclic influenzas are zoonoses from wild ducks, and especially in China they transfer to domesticated ducks, then to pigs, and humans.