This is just a bunch of plots with no effort to engage with the existing literature and study. Frankly, it is a waste of time trying to draw conclusions about global warming from this.
I don't think the author adequately considers changes to the local environment of the thermometer, changes in the equipment itself (eg replacement, movement) possible changes in recording methodology and so on.
There was no real effort to understand the possible sources of noise or error in the measurements.
Also, 1920 is a very arbitrary starting year. Why then?
In 1920 the Industrial Revolution has been going on for over 100 years, the US petroleum industry was already big enough to have been affected by antitrust action, and Henry Ford's assembly line has been enabling mass motorization for the better part of a decade.
That would be a testable hypothesis that you have not tested. Anybody can do whataboutism but it isn't a meaningful argument. If it's your belief that the literature is biased by 'green' funding, prove it.
Engaging with the existing literature would be a good start.
If you were interested in studying the relationship between bias and funding you might do a survey of published papers and articles on the subject.
If you can identify some measurable criteria that can be used to rate how "green" a paper's funding is then you can use that as an axis and compare the surveyed papers to reveal trends.
It's too bad that humanity hasn't figured out a way to record and share and pool knowledge yet, but them's the breaks.