Buzzing around the blogosphere is news of a paper in Nature Climate Change that may have put the cats among the pigeons – although the Team appear not to be impressed. At http://phys.org/print261048731.html … the new graph appears to show the Roman and Medieval warm periods were somewhat warmer than today – without any excess levels of co2 in the atmosphere. The actual average temperature over those 2000 years seems to show a gradual cooling – from the Roman climate optimum. However, such averaging techniques can produce a graph that is meaningless. The tactic is commonly used by climate scientists, a favourite tool of the CAGW doomsayers, that is usually restricted to something like a couple of hundred years in duration. It begins at the point the world was emerging from the Little Ice Age and there accentuates any warming that has taken place in the 20th century. It is a ploy that has deceived a lot of otherwise intelligent people – but is essentially meaningless. Like the emphasis on the average in this paper. If the graph was extended another 1000 years the trend may be completely different. However, the fact that climate scientists are no longer hiding the fact that the Roman and Medieval warm periods were indeed as warm if not warmer than modern times is somewhat refreshing. The instigators of the hockey stick will of course say otherwise until they are in their graves.