I should grudgingly credit Andrew Montford for this. I'm barely a third of the way through the Hockey Stick Illusion which I am finding a little tedious. Montford is telling the story of McIntyre's efforts to unpick Dr Mann's work. But the importance of the Mann et al ( Hockey Stick ) graph is widely overblown , it is not as if climate science rests on it. A major premise of the book is that the Mediaeval Warm Period was warmer than current estimates, which supports the view that recent warming is part of natural variability. And this can be used to support the argument that recent warming is not anthropogenic which can then be used to imply that claims by climate scientists that warming is anthropogenic are dishonest which is the sort of logic that underpins the Cuccinelli case and indeed much of climategate.
A rational person would get off that particular rhetorical bus before it steers off the improbable cliff of absurdity.
I wonder therefore what the causes of the MWP are, and expecting to find the phrase 'Milankovitch cycles' consult Skeptical Science. Regrettably, the answer is not so simple. The Mediaeval Warm Period was ( I think) regional not global and, it is due to solar irradiance which IMHO would bathe the entire planet. This presents a contradiction. I have posted at 27 and 31 and until I get a satisfactory answer will consider myself a climate skeptic. Does this shake my acceptance of AGW? Yes, like a fruit fly landing on a slab of granite. My understanding of climate science is incomplete and imperfect just like everyone elses. I don't know whether SkS will answer my questions in this regard to my satisfaction but my fellow skeptics I have to tell you that the political issue is the sharp warming of modern times and whether we allow that to go on into the future, not what the weather was like half a millenium ago. Allowing our concerns about uncertainties in the paleological record to systematically influence our politics is denialism not skepticsm.