Speaking of eggheads...Math is for eggheads.
Charts are pretty, but let's see the math ... no correlation is there? ... 1,360 W/m^2 then, now, and in the future ...

Milankovitch (Orbital) Cycles and Their Role in Earth's Climate - NASA Science
Small cyclical variations in the shape of Earth's orbit, its wobble and the angle its axis is tilted play key roles in influencing Earth's climate over timespans of tens of thousands to hundreds of thousands of years.

Apparently the sun's intensity doesn't have to change for the sun to play a role in our climate. That coupled with certain background conditions can explain our climate changes.