by P. Homewood, November 28, 2017 in NotaLotofpeopleKnowThat
We are all too familiar with graphs showing how much global temperatures have risen since the 19thC.
The HADCRUT version above is typical, and also very precise, with fairly tight error bars even in the early part of the record.
One wonders where they got the data to work all this out, because it certainly could not have come from thermometers.
All of the major global temperature datasets rely heavily on the Global Historical Climatology Network (GHCN). Yet as the “Overview of the Global Historical Climatology Network-Daily Database”, published by Matthew Menne et al in 2012, rather inconveniently showed, most of the world had little or no temperature data in the 19thC, and even up to 1950.