True, in the sense that the climate is always changing and always has. I don't think we have a handle on which direction it's currently going or how fast. Just witness the recent revisions to NASA's climate records in the USA and Mr. Hansen's continued efforts to cover up his methodology for calculating *past* climate - and that's just here in America!
Beyond that, the continuing documentation of the hilariously bad siting of many of the measurement stations (next to air conditioning exhaust, on an asphalt parking lot, etc.) when such stations were in the middle of a field fifty years ago renders any conclusions drawn from their measurements highly suspect. And that's just here in America - the rest of the world's records are likely in far worse shape.
So I'm not sure how one would go about making a *credible* claim (keeping in mind that repetition is not the same as credibility) that we have a good handle on even the current situation, much less future climate changes.
Agreed. Good, logical post.