I have often shared with you the evidence that the story of anthropogenic global warming is a story created to justify Agenda 21, perhaps the earliest being this one which demonstrated how the original warming hockey was statistical nonsense. I have also shared with you how the historical temperature data has been tweaked to emphasize the degree of apparent warming. Australia, also.
Now, there has been a very interesting graph released by NOAA showing the degree of adjustment by the US.
The amount of claimed global warming is about 1 degree C over 100 years. As can be seen here, comfortably a third of that can be explained by these adjustments.
Mind you, the amount being discussed here is minuscule when you look at the historical patterns of temperature fluctuation.
These adjustments are also discussed in this video.