A post by Judith Curry discusses the “Early 20th Century Warming,” i.e. the rise in global mean temperature during the early 20th century. True to form, Curry can’t get past the first sentence without telling the kind of whopper which shows how little she understands about the topic she has chosen:



A careful look at the early 20th century global warming, which is almost as large as the warming since 1950.



Bullshit. I’ve heard this bullshit before.



Deniers have made the claim for at least a decade now, in fact they have even faked graphs to make the claim. So what the hell is Judith Curry doing saying so? How much did the globe warm in the “early 20th century,” and how much “since 1950?” Does Judith Curry even know?

I doubt it.

Let’s take global temperature data, and fit a smooth curve to the data since 1900. That way we can reduce the amount of random fluctuation, giving a closer look at the trend, what global warming is really up to. Then let’s estimate “early 20th century warming” as the total range covered by the smooth estimate between 1900 and 1950. Next, we’ll take the difference between the 2018 value and the 1950 value to estimate the warming “since 1950.” We’ll start with the data from NASA:

The early warming amounted to 0.31°C, but since 1950 it has risen 0.86°C, which is 2.8 times as much. Do you really think it qualifies as “almost as large” when the recent warming is almost three times as big?

NOAA data say that recent warming is only 2.56 times as large as early warming:

For the HadCRUT4 data, recent warming is a “mere” 1.85 times as large as the early 20th century warming!

I just got a message from Peter Dinklage, saying that he’s “almost as large” as I am. I informed him that I had sent a similar message to Kareem Abdul-Jabbar.

The data from Cowtan & Way have recent warming 2.04 times as big as early warming:

The data from Berkeley Earth have the ratio at 2.05:

Curry does at one point admit that for data covering land areas, the warming since 1950 is “substantially” more than during the early 20th century. That’s kind of hard not to admit, when the recent warming is over three times as large as early warming:

Convincing anyone that it’s “almost as large” as something three times as big … that’s a hard sell, even to gullible climate deniers.

Why Curry is invested in this dumb idea, is revealed by her second sentence:



Until we can explain the early 20th century warming, I have little confidence IPCC and NCA4 attribution statements regarding the cause of the recent warming.



Here is my opinion.

Judith Curry doesn’t want anyone to believe that modern warming is due to man-made greenhouse gases (or anything else man-made). Therefore she uses the early 20th century warming, about which we know but little, to make the case that “if we can’t understand then, how can we understand now?” To get this case to work, she has to portray the early 20th century warming as being comparable to modern warming, so that’s what she says (her exact words: “almost as large”), with no evidence to back it up. God forbid she should actually have to calculate some numbers! It’s not her strong suit.

Seems to me, this is just like saying “Look! There was a spike in lung cancer deaths in this region, before the introduction of tobacco. Until we can explain the early lung cancer outburst, I have little confidence in WHO and CDC attribution statements regarding the cause of the recent elevated lung cancer rates.

Yes, folks. That’s really what Curry and her ilk are doing. They do it a lot. There’s something we don’t understand, so we don’t understand anything! If they have to exaggerate to make their case look plausible, they will. At least, that’s my opinion.

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