Pat Michaels was at my presentation yesterday and pointed out at minute 56 that one of the reasons temperature representations have changed is because of the inclusion of southern oceans into the global temperature record.
Answering Pat, the main graphics I used were comparing 1975 Northern Hemisphere temperatures vs. 2014 GISS Northern Hemisphere temperatures, and shows a sharp discrepancy between 1910 and 1940.
Also, a 1978 NOAA report actually showed more cooling in the Northern Hemisphere from the late 1950s at altitude (radiosonde) than at the surface. And the global representation from that report showed very similar global cooling at altitude as at the surface. So I don’t think that Pat’s objection really impacts the message I was presenting.