Summary for Policymakers published

The IPCC AR5 WG1 Summary for Policymakers has now been published.  Rumours of a delay proved unfounded and the SPM was posted at the WG1 website at 9am UK time as planned.

Recall that the full report is due to be published on Monday.

Here’s a quick look at some of the points:

  • “It is extremely likely (95%) that human influence has been the dominant cause of the observed warming since the mid-20th century”
  • No best estimate of climate sensitivity, but a likely range given of 1.5 – 4.5C.  The low end  is slightly lower than it was in AR4 (2.0).
  • Misleading graph of ocean heat content
  • Graph of snow cover for March/April only
  • Decadally averaged temperature graph (hide the decline?)
  • Graph of Arctic, but not Antarctic, sea ice.

Each of these issues will be discussed in a separate post.

What other notable points are there?

5 thoughts on “Summary for Policymakers published

  1. ie SPM AR4 says:

    “Antarctic sea ice extent continues to show interannual
    variability and localised changes but no statistically
    signifi cant average trends, consistent with the lack
    of warming reflected in atmospheric temperatures
    averaged across the region. ” (pg 9)

    AR5 brings in graphics of Arctic Sea Ice extent, but leave out Antarctica

    Yet: the recent Met Office report, shows a trend in Antarctic sea Ice extent (upwards) (pg 18) which is missing from SPM AR5

    actually a good chunk of these Met Office reports especially graphics) seem to be in SPM AR5

  2. The decadal graph of temperature jumped out at me. those slabs of horizontal lines convey a simple message: “no change for ten years” is normal. It’s amusing that Skepticalscience used a rather similar graph which they attributed to sceptics.

  3. @Barry September 27, 2013 at 9:44 am:

    actually a good chunk of these Met Office reports especially graphics) seem to be in SPM AR5

    Hmmm … interesting! If I might be forgiven for quoting my observations from July, when these reports appeared:

    “For me, the major takeaway from these three papers was highlighted by [Judith] Curry in the intro quote of her post:

    The recent pause in global surface temperature rise does not, in itself, materially alter the risks of substantial warming of the Earth by the end of this century. – UK Met Office [emphasis added -hro]

    “So the bottom line seems to be that this “pause” – which the Met Office and others have spent at least the better part of a year, in effect, insisting was not occurring and berating those who had the temerity to observe that it has – has finally been acknowledged!

    “But (in keeping with past “standard operating procedures” on far too many such dragged out acknowledgments), the “experts” have, in effect, pronounced that “it doesn’t matter, anyway … our models continue to rule!”

    “I could be wrong, but my guess would be that this is a rather determined and elaborate exercise in “spin” ahead of the Sept. “approval” of WG1′s contribution to AR5, in order to … uh … sustain what former UNFCCC head honcho, Yvo de Boer had declared last November:

    “That [AR5] report is going to scare the wits out of everyone,” Mr de Boer said in the only scheduled interview of his visit to Australia. “I’m confident those scientific findings will create new political momentum.”

    “Not to mention that there appears to be no mention of the simple fact that even if the output of their gloriously faulty – if not significantly deficient – models turns out to be correct, they still have absolutely no empirical evidence (nor even a sustainably “alarming” correlation) which would support the hypothesis that the primary “culprit” is human-generated emissions of CO2. But perhaps this is not a message that the “experts” want to convey to the policymakers – or to the public!”

    In hindsight, I think it’s also worth noting the rather curiously lengthy “lag” in the Met Office’s acknowledgement (and very recent attempted dismissal of) Nic Lewis’ comment of July 23 (and his subsequent expansion of this):

    Writing as an author of the study, I think that the Met Office paper 3 factually misrepresents the results of Otto et al (2013) in more than one place. [emphasis added-hro]

    As I had noted in July … “spin” is one thing, but “factually misrepresent[ing] results … in more than one place” is a completely different kettle of (distinctly malodourous) fish, IMHO.

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