[RobSutton]

These are old and well rehearsed arguments that simply cherry-pick sets of data for regions of the world that happen to fit in with the views of the climate sceptics. For each of these periods whether warm (mediaeval warm period) or cold (little ice age) there are other data sets for other regions that show the opposite pattern. They all need to be averaged out to give a global temperature or at the very least a hemispheric temperature. Manns "hockey stick" graph is based on such global averages and are not simply figures for odd regions of the world unlike the studies you higlight. Yes bits of Western Europe or China might have been warmer in the mediaeval warm period - others bits of the world were not and on average neither was the world.

I get the feeling that there really is no further point in me continuing in this discussion the overwhelming body of evidence collected by climate scientist points in one direction, you can select odd little bits of data to support your own agenda or indeed any hypothesis and that is all you are doing.