As far as I can tell, predictions of a cooling trend "over the next few decades" are not based on anything resembling science, so where did this prediction come from? Is it one of those complicated things that no-one really understands (except you)? I haven't found a thing that corroborates this cooling, in fact NASA is predicting more sunspots for cycle 24, which starts real soon now. We are, of course, currently at the bottom of the 11-year cycle, so that solar activity is at a minimum. And that prediction - of more activity, not less, is based on some fairly solid observational methods.