The EPA used to have this inconvenient document on their web site, showing about 0.2C cooling from 1940 to the 1960’s
Figure 2-1. Global temperature trend for past century based on J. Hansen 1981
At the time, scientists unanimously agreed that the world was cooling.
That cooling didn’t fit the global warming agenda, so NASA simply got rid of it. They now show warming after 1950.
I digitized the 1981 graph and calculated the alterations NASA has made to their own global temperature record since 1981. They progressively cooled the past to exaggerate warming, with most of the data tampering coming between 1940 and 1960 – in order to eliminate the post 1940 cooling trend.
When you are saving the planet, sometimes you just have to alter the data. Gaia demands it.