In 1978, NOAA showed 0.6 degrees global cooling since 1975 at the surface and in balloon data. The cooling was present in both hemispheres.
The National Academy of Sciences knew about this cooling in 1975.
This cooling was seen in the vast majority of US stations and is still present in the untampered US data.
But for some reason, the cooling has disappeared from NASA data.
NASA used to show the cooling, but have since made it disappear.