[jfengel]

The paper notes that 1899 was an extreme cold event -- an order of magnitude greater than average. Pick any other starting year and the trend becomes vastly smaller.

It's hard to tell if that's just bad data collection in 1899, perhaps a genuine cold snap exaggerated by data gatherers seeking extremes.

There's a similar magnitude of hot snap in 1936 that dwarfs every other one, and that's not simply cherry-picking on Christy's part, but it was confined to North America. Globally 1936 was not especially hot.

Regardless, as TFA says, "Extreme cold has decreased sharply." Cristy is trying to claim that extreme heat has also decreased, but I don't think he's evaluating the data critically.