In 1990, NOAA published this graph of troposphere temperatures. showing 0.6C cooling from the 1950’s to the mid-1960’s, and little or no net warming from the 1950’s to 1990.
This was also seen in Briffa’s tree rings.
But if we look at current versions of NOAA and NASA temperatures, the 1950’s cooling no longer exists. The red line below is NASA 2016, which shows the same 1960 to 1980 warming as radiosonde, but does not show the 1950’s to 1960’s cooling.
One reason we know that the cooling was real, is because during the 1960’s glaciers in Norway were growing for the first time in 200 years.
NASA and NOAA are hiding the post 1940 decline in temperature and 1970’s ice age scare, because it doesn’t fit their political mandates. It has nothing to do with science.