[bobthepanda]

These plots, of these specific points of this dataset don't show extreme effect.

These are just arbitrary cities.

Not to mention that, most climate change stuff looks at the start of the industrial revolution, so a starting point of around 1920 is going to necessarily look a lot different.

[mwint]

Why would the start point make a big difference? Is the assertion that if it started at 1820, you’d see a stair step and then flat from 1920 on?

Either way, these graphs look flat from 1920 on. That’s the point of the article.