Paper: ‘no clear increase in blocking’

US-blockingA paper, accepted for publication in Geophysical Research Letters just two days ago, challenges the warmist hypothesis that reducing ice in the Arctic is causing more blocking events resulting in more frequent instances of extreme weather. The paper, by Elizabeth Barnes, is available in PDF here.

Given the weather in the US at the moment (see previous post here), which the headbangers are using as evidence of extreme weather arising from Arctic warming, the paper shows how difficult it is to make such a link. From the abstract (my emphasis):

Observed blocking trends are diagnosed to test the hypothesis that recent Arctic warming and sea ice loss has increased the likelihood of blocking over the Northern Hemisphere. To ensure robust results, we diagnose blocking using three unique blocking identification methods from the literature, each applied to four different reanalyses. No clear hemispheric increase in blocking is found for any blocking index, and while seasonal increases and decreases are found for specific isolated regions and time periods, there is no instance where all three methods agree on a significant trend. Blocking is shown to exhibit large interannual and decadal variability, highlighting the difficulty in separating any potentially forced response from natural variability.

Of course, the paper has provoked the ire of the true believers, in particular a certain Jennifer Francis, for whom this appears to be her pet theory. She gave an interview back in August last year, when the paper was first made public, in which she questions the ‘motivation’ of the author, and labels Barnes’ approach “less than objective” and “a direct attempt to disprove [Francis’] work”.

Judith Curry expresses the views of the majority reading such comments:

So why on earth would Elizabeth Barnes be out to ‘get’ Jennifer Francis and discredit her work?  Its very hard to imagine a reason, beyond the obligation of a scientist to challenge existing findings and push forward at the knowledge frontier.

JC message to Jennifer Francis:  I’ve found that your credibility is reduced and your own motivations are questioned when you attack the motives of another scientist, particularly a young scientist without any apparent agenda beyond doing good science and advancing her academic career.  The high ground is a much better place to be, and not just in a hurricane.


  1. Ahh, but radio national had Biologist Reece Halter saying that global warming is causing the extreme cold. Lord knows why they think a plant physiologist with a 15 year old PhD on snow gums would be expert. But, that’s the ABC for you.

  2. Lew Skannen says:

    AGW causes everything.
    So when I am put on trial for Global Warming Heresy I will just claim that my skepticism is a direct result of global warming and beyond my control.
    Not sure how the Grand Inquisitor will handle that one as it presents him with a bit of a paradox.

  3. Hang on … we’ve been told for years by apparent top climate scientists to expect less snowfalls, climate models predict warmer winters, ex-politicians claiming ice-free polar caps, hand-wringing news articles of children who would never experience snowfalls, on and on … but now we’re expected to believe exactly the opposite because that’s what’s happening now.

    Gimme a break warmanista’s … your theory is cracking at the seams!

  4. Will J. Browne says:

    Hi Simon. I’m a little confused by this post. Elizabeth Barnes, a climate scientist, published a paper that contradicted findings by another climate scientist, Jennifer Francis, who then criticised the findings of the first scientist, Elizabeth Barnes. Then a third climate scientist, Judith Curry, gave hell to the second scientist for her response to the first scientist. My question is: Which ones are the group thinkers?

    • I’m sorry you are confused, it is pretty clear to me. Scientists should not criticise other scientists in the manner of that by Francis on Barnes. Curry pointed this out. End of story.

      • Will J. Browne says:

        I thought they didn’t criticise each other. I thought they all agreed with each other on everything.

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