I've been saying for years that surface temperature measurements (and long term trends) have been affected by encroachment of urbanization on the placement of weather stations used to measure surface air temperature, and track long term climate. In doing so we found some hilariously bad examples of climate science in action, such as the official USHCN climate monitoring station at the University of Arizona, Tucson:USHCN weather station in a parking lot. University of Arizona, Tucson
I have published on the topic in the scientific literature, and found this to be true based on the science we've done of examining the USHCN and applying the siting methodology of Leroy 2010.
In Fall et al, 2011 we discovered that there was a change to the diurnal temperature range (DTR). It decreased where stations had been encroached upon, because of the heat sink effect of man-made materials (asphalt, concrete, bricks, etc.) that were near stations.
The number of sites not meeting official NOAA standards is more than 10%. You get up over a third, stupidity isn't an explanation anymore. That's a deliberate campaign. Its corruption.
But the surface monitoring system does not exist like an island, whole and complete, isolated unto itself. The same organization that allowed so many surface temp stations to be corrupted also controls all the other monitoring systems, and the record keeping as well. Do we actually know what the temperature was on May the 15th 1927 in Topeka Kansas? Or did they corrupt the records too? Did they corrupt the satellite data?