In 1981, NASA showed the 1930’s as the warmest decade globally.
That didn’t suit the global warming narrative, so by 1999 they had almost erased the warm 1930’s
However, the small bit of warming from 1940 to 2000 didn’t suit the needs of the Hockey Stick, so NASA has since completely erased the warm 1930’s
The animation below shows the changes NASA made to the global surface temperature record between 1981 and 1999, and then from 1981 to 2014.
From: Tom Wigley <email@example.com>
To: Phil Jones <firstname.lastname@example.org>
Date: Sun, 27 Sep 2009 23:25:38 -0600
Cc: Ben Santer <email@example.com>
It would be good to remove at least part of the 1940s blip, but we are still left with “why the blip”.