By the 1930’s and 1940’s, the Arctic had warmed 10 degrees, the glaciers of Norway and Alaska had lost half their mass, the glaciers of Greenland and Norway were nearing catastrophic collapse, and glaciers were disappearing all over the world. NASA responded by tampering with the thermometer data to make the warmth disappear.
13 Jan 1939 – RIDDLE OF THE GLACIERS. – Trove
17 Dec 1939, Page 15 – Harrisburg Sunday Courier at Newspapers.com
31 May 1947 – TEMPERATURES RISING IN ARCTIC REGION – Trove
18 Feb 1952 – POLAR ICE THAW INCREASING – Trove
Here is NASA’s response. They simply cooled the past to make the prior warmth disappear.