Do not use the term “climatologists”. Since the study of climate is a legitimate field of study, don’t give it the sense of being false because a group of very poor scientists have attempted to use scare tactics to gain research grants.
The record of ground based temperature were changed circa 1999. https://stevengoddard.wordpress.com/2013/08/16/nasa-massively-tampering-with-the-us-temperature-record/
Also there is clear evidence that NOAA has been manipulating data with an end result intent: http://jennifermarohasy.com/2009/06/how-the-us-temperature-record-is-adjusted/
Further proof of the changing data with no purpose other than to build a case for something that isn’t apparent in the data is here: https://wattsupwiththat.com/2013/01/18/hansens-nasa-giss-cooling-the-past-warming-the-present/
The end result of all of this is that the people maintaining the temperature records at both NASA and NOAA should be immediately discharged. These indications of “man-mad global warming” have NOT been either factual or accidental and this sort of thing demands prosecution.