Michael Mann's 'Hockey Stick Chart' (that Bellcurve takes a tiny snippet from the very end of ) adopted by IPCC completely deletes the Mediaeval warm period plus the warm 1930 - 40 The bottom chart shows actual temperatures over mostly the same time period. Why the deception? This shows how NOAA and Bellcurve are dishonest and deceptive using that 'Bellcurve" chart as proof there is a climate crisis.