David wrote:
>I can’t immediately find a sentence which says they are looking at historical recordings of temperature at weather stations.

As said above they wrote:

>GHCN-M and Hadley Centre data was ignored in favor of other data sources when possible

Sofar I know these two centres are THE centers for collecting global temperature measurements. I haven't heard of that the data at GHCN-M and Hadley centre was manipulated but if this was so then this would of course be troublesome. Do you know on which incident this assertion is based? Was there a cyber attack? Don't they have still unmanipulated copies at the centres? If not then one should may be ask publicly wether people hold still some old unmanipulated files, like I have a copy of the Hadley temperature anomalies from march this year.

So I guess IF this should be real measured data what they use then either the Berkeley earth people picked up the data from local weather stations and archives themselves or there are other centers, which we do not know about like I could imagine that
central intelligence services of some countries might have collected that data as well, since well this is of course vital information for the
survival of each country. So maybe Berkeley earth people have special access to classified temperature data that might explain their cautious wording.