What does this say about the proxy and other past records we used before they did (which were also the basis of the IPCC's very existence?).
Form of individual corrections applied by NOAA. The black line is the adjustment for time of observation. The red line is for a change in maximum/minimum thermometers used. The yellow line is for changes in station siting. The pale blue line is for filling in missing data from individual station records. The purple line is for UHI effects (this correction is now removed).
Alabama, 1F in a century, all artificial
Now looking at this motley collection, what do they all have in common? Yes, they all started flat and sloped up. Don't ask why, no one knows. Feed it all into the global set and what happens to it? As above, so below, these alterations done at the local level are all collected together and form the ones we have our policies made with, although if you take the adjustments away in reverse it won't have a hockey stick at all.