“The periodicity is about 12,000 years.
The last one was about 12,000 years ago...”
One of my pet theories is that Ice Ages are caused by the solar system entering a narrow band of cosmic dust. Thereby reducing solar energy reaching Earth, Sometimes the dust is thicker sometimes not so much. If narrow enough would be hard to detect until fairly close. 12,000 years ago fits in with the end of the last Ice Age. If the dust happened to occur during a prolonged solar minimum that could magnify the effect.
Like, for example the sudden irregular dimming of Betelgeuse?
You'd love suspicious0bservers, especially the Sun, Earth, Space News section.