For my update I've used CRUTEM3v, expecting them to be rather similar but with a few more years on the end.
But the pre-1930 temperatures are now very different, being much cooler (by > 0.5 degC for a 25-year low-pass mean) in CRUTEM3v than CRUTEM2v. Previously they had been, on average, near or even above the 1961-1990 mean, now they're at -0.5 degC.
Is this a result of some homogenization work on New Zealand summer temp data? Or just some random artefact of minor changes somewhere?
Climate Negotiators Give Up On Enforceable Paris Deal
24 minutes ago