No real mystery here. Its been shown that there's a correlation between solar wind, and berylium isotopes on earth. The berylium isotopes get formed though the interaction of cosmic rays and solar wind, and it is generally agreed that cosmic ray levels are pretty much constant. Subsequent research with respect to berylium isotope levels has shown an uncanny correlation to periods of higher and lower global temperatures. The inference was made that somehow solar activity has an extremely enormous influence on the earth's environment. Research has uncovered a huge increase in berylium levels over the last century.
Since man's emission of greenhouse gases is responsilbe for global warming, mans activity must somehow be influencing the intensity of solar intensity. Its stands to reason then, that this influence by man on the sun should be observable being made manifest on other planets within the solar system.
It would not be a great leap then to conjecture that the solar component of galactic cosmic flux MUST be influencing other stellar systems, and by extension other galaxies, also. Man's activities are truly galactic in consequence and MUST be stopped before man makes a total wreak of the entire cosmos. Think about that with the next match you light. Chaos theory postulates the "Butterfly Affect" wherein, with with the lighting fo that cigarette one not only is indiscriminately and with utter wanton abandon subjecting each and every being around onself for miles to oncological hazard, but effectively have extirminated a hereto unknown and unnamed species of gleeperwoxneeklerites that will now NEVER know existance.
I agree with TexasGreg -- impact structures -- but I'm not going to reply directly to him because of the age of the topic. :')