I think if you were to watch the sun in time lapse over hundreds of years you would see it flicker like a flame.
I am not sure if there is any science that shows the output is constant, maybe I am wrong.
But if it does (even just a few degrees) the heating and cooling of the earths crust could easily trigger earthquakes
Maybe even more than that considering the earth get's 15% more light power in Dec. than July because of the orbit variation, and that's a 26,000 terra watt surge yearly. There's also big variations w/ the various cycles over the years --it all makes green house claims look silly 'cause there's just no way of predicting heating affects.
As for earthquakes, the temp. increases a degree F per 70 feet and the quake's depth it was about a thousand degrees hotter anyway.
Not sure either if it is a hard predictable science, but they are pretty certain we are not causing any climate changes, hot or cold. It's our sun that determines that.