“Evidently Javier was unhappy about NSIDC using daily data on sea ice extent to show that this year had the 2nd-lowest annual minimum on record. So, he decided to go with the September monthly averages for each year, and to start with 2007 to show a “trend” which, he says, shows “that Arctic sea ice has been increasing since that fateful September of 2007.”

Gosh, Javier, what was that you were saying about “The trend is always determined by the choice of starting point and ending point“? Didn’t you “Do your homework“?

Of course the trend isn’t determined by the choice of start and end points, but it’s strongly influenced by it. That’s especially true if you start (or end) with an extreme, which I discussed here. And that’s exactly what Javier has done: start, not just with the most extreme September average in the record, but one so extreme he himself refers to it as “fateful.”

Javier has also resorted to another denier favorite: computing a “trend” based on a time span that’s way to short. Way too short. Ten years, from 2007 to 2016. And, in classic fashion, he omits to estimate any uncertainty with that “trend.”

Let’s do the math for him.”


“The time span is so short that the uncertainty in any trend estimate is gigantic. In this case, it’s so big that there’s really no evidence sea ice is declining any more slowly than it was before. There’s no evidence that the recent apparent trend change is anything more than a fluctuation which looks like one.”


Furthermore, from before

What kind of maths requirement did your PhD in biological sciences entail, grade 8? What an embarrassment!

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