The estimate of uncertainty on those old devices have to be, at a minimum, plus or minus one degree. It is remarkable - and a bit frightening - that no one on the climate change side bothers to think about that.
But if you were to bring that up at a climate conference, you'd be shouted down. You'd be labeled a denier, a hater of mother earth. Science has gone from the inquiry method to the fascist method.
Then it’s no longer science, of course. The scientific method has been abrogated.