USHCN published the graph below indicating the total size of their temperature adjustments - about 0.5 degrees and flat after 1990. I doubt that these adjustments are legitimate, but that isn’t the point of this post.
The smoking gun is that their actual adjustments are much larger, are offset by 2.5 degrees, and that they increase exponentially after 1990 – instead of going flat as they claim.
The graph below shows the actual adjustments in blue, and the documented adjustments in red. They don’t even vaguely resemble each other. USHCN adjustments are being used as the basis of NOAA claims that 2012 is the hottest year ever – a claim which is not borne out by the temperature record.