It's interesting to compare Phil Jones' various prognostications on the reality or otherwise of the Medieval Warm Period.
Jones et al 1998:
..we can only concur with Hughes and Diaz (1994) that there is little evidence for the
‘Medieval Warm Period’, although it is variably quoted as occurring between 900 and 1200...From the few reconstructions used prior to 1500 there is little evidence for the ‘Medieval Warm Period’.
Jones and Mann 2003:
To the extent that a ‘Medieval’ interval of moderately warmer conditions can be defined from about AD 800–1400, any hemispheric warmth during that interval is dwarfed in magnitude by late 20th century
Jones & Mann 2004:
Our assessment affirms the conclusion that late 20th century warmth is unprecedented at hemispheric and, likely, global scales.
BBC interview 2010:
There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia. For it to be global in extent the MWP would need to be seen clearly in more records from the tropical regions and the Southern Hemisphere. There are very few palaeoclimatic records for these latter two regions.
One striking feature of the recent statements are that the disappearance of the scare quotes from the medieval warm period. But the overall tone has changed too. This looks like a pretty clear change of emphasis to me, but I'm sure that there are those who will argue that his latest statement is, in Hockey Team jargon, "consistent with" his earlier positions.