1950s? Nobody was looking for “global warming” back then. And NOAA as we know it was established in 1970, so they cannot have made any measurements two decades before their existence. Not to mention, the methodology cannot be the same at all locations due to conditions.
The National Weather Service actually dates back to 1870. (Executive order President US Grant.) Back then I imagine all it was doing was recording temperature, barometric pressure, rainfall and wind direction/speed. It’s first director was one of the father’s of meteorology. Don’t remember his name.
The difference between then and now is the CO2 measurements were science, and the current alarmist dogma and memes are part of the global warming agenda that has gone well beyond the bounds of science.
The CO2 measurements and the fossil burning attribution are still accepted science and have not been overturned or questioned in any substantial way. NOAA has picked up the facility at Mauna Loa but the measurements there remain the same accepted science being performed since the 50's. The remaining questions are mainly around attributing some amounts of the rise to changes in vegetation (e.g. burning the rain forests)