re: Cosmics and climate
There's an obvious climactic cycle that runs about every 100,000 years, and while I've seen a number of papers putting forward various theories on this, including astronomical ones, I have not seen anything that nails it down tight.
If I read that paper right, and I just skimmed it, the time taken to traverse one of those clouds is around 40-50,000 years, or only about half a climate cycle. That doesn't look good for a "cause and effect."