I have written many times about what I consider the worst scandal in the history of science: efforts by the curators of global temperature records to rewrite the past so as to produce an illusion of warming that is not reflected in the temperatures that have actually been recorded.
No Tricks Zone picks up the theme in a post titled “Adjusted ‘Unadjusted Data: NASA Uses The ‘Magic Wand Of Fudging’, Produces Warming Where There Never Was.”
It’s been long known that NASA GISS has been going through its historical temperature data archives and erasing old temperature measurements and replacing them with new, made up figures without any real legitimate reason.
This practice has led to the formation of new datasets called “adjusted” data, with the old datasets being called “V3 unadjusted”. The problem for global warming activists, however, was that when anyone looks at the old “V3 unadjusted” – i.e. untampered data – they often found a downward linear temperature trend. Such negative trends of course are an embarrassment for global warming alarmists, who have been claiming the planet is warming up rapidly.
So what to do? Well, it seems that NASA has decided to adjust its “V3 unadjusted datasets” and rename them as “V4 unadjusted”. That’s right, the adjusted data has become the new V4 “unadjusted” data.
You can’t make this stuff up.
You guessed it. The new V4 unadjusted data are now yielding warmed up trends, even at places where a cooling trend once existed.
This is how NASA uses its magic wand of fudging to turn past cooling into (fake) warming.
The post includes a number of examples, animated GIFs that show how the temperatures originally recorded in a given locale have been changed by NASA to create an alleged warming trend. Here is just one, Marquette, Michigan, from 1880 to 2018, where NASA has “turned a slightly cooling trend into a robust warming trend.”
Much more at the link. The bottom line is that surface temperature data have been hopelessly corrupted by partisans, and can’t be trusted to show temperature trends. The only data that are publicly available, transparent and reliable are the satellite readings that go back, as I recall, to 1979.