What I want to know is what causes the major drop to begin. You can see the Toba drop at 74,000 ya, and I know that 22,000 ya Sakurajima blew out a 15 mile diameter crater and there were several other large volcanoes around that time also. If we had the chart going back a million years we could see if Yellowstone, about 640,000 ya had an impact as well as Long Valley in the 700ks
Dang, it’s cold out thar!
Glaciation to miles of depth of ice results from energy, not from cloud cover, IOW, the ice ages were rapid-onset and resulted from large impacts on the oceans.