I basically agree with your post.
My question is whether human activity is the primary cause. It seems plausible to me that human activity increases CO2 production, greenhouse effects occurs, etc. However, it also seems plausible to me that increased solar activity could be a major (primary?)cause of earth warming trends, both because of the increased energy (photons and magnetic) hitting this planet and the release of CO2 from warmer ocean waters (a double whammy).
Here is just one of the sites I see when I Google "sunspots global warming":
http://www.space.com/scienceastronomy/sun_output_030320.html
It seems to me that there are a lot of unknowns. This notion of solar activity playing a role doesn't seem to get much attention.
