Paul Homewood noted on his blog that NCDC has lowered global temperatures by several degrees since their 1997 version. There is a scandal here, but it isn’t necessarily that they lowered the temperature.
The problems are that as of 1997 they didn’t even pretend to have accurate long term records of sea surface temperatures, and that they have tampered with Southern Hemisphere temperatures.
The graph below shows how fake the Southern Hemisphere temperature data is. As of 1978 NOAA showed the Southern Hemisphere extra tropics surface temperatures cooling from 1958 to 1977
GISS now shows the same period warming in that region.
They accomplished this by massively tampering with data in places like South America, turning cooling into warming. Paul uncovered the damage NCDC and GISS were doing in South America.
GISS didn’t even start publishing pre-1950 land/ocean temperatures until about 2003, because they knew the data was inadequate. Now they mix in fake ocean data and tampered surface data, to make a 100% fraudulent temperature record.