I agree wholeheartedly that we are in a global warming trend but do not agree with his reference to the Sun's relative inactivity contributing to a slight cooling effect. This is backwards. When astronomers refer to the Sun's activity they mean level of Sunspot activity. Sunspots are massive magnetic storms whose frequency run in 11-year cycles. Sunspots are areas that are much cooler than surrounding areas. At peak activity this reduces the sun's total heat output. We are not at peak activity right now, just the opposite. The Sun has indeed been in an inactive trough and thus hotter than would normally be the case.

I think this is another case of a well meaning scientist who got one of his facts wrong. Unfortunately, this is just the sort of bad astronomy we don't need for the global warming discussion.