When a despotism gets a bit of freedom, it gets a bit of economic growth, and that has military potential. There is precedent for this kind of thing. Fortunately, most of the other talks were of far higher caliber, utterly devastating to orthodoxy on a variety of issues. But UVB varies normally with latitude, twice as high in El Paso as in Minneapolis. Carbon dioxide, even in total, is a small player, so the effect of changes in carbon dioxide is even smaller.
Sunspots cause variations in solar brightness.
This provides a way to track pre-historic sunspot cycles. Sunlike stars have starspots, just as the sun has sunspots. Baliunas is one of the leading investigators of starspots. She is co-author of a recent article in Scientific American which presents studies of the spot cycles of many sunlike stars. Stars have Maunder minima too , and one has even been caught entering such a period when spots are rare.