Sea level rise from IPCC ’90

This starts from Pielke Jr commenteing at RC that the 1990 IPCC grossly overestimated sea level rise to date, and pointing to his post here as proof. Its nonsense, of course.

[Aside: Chinese Cut Back Coal-to-liquids from John Fleck is interesting.]

Pielke does the familiar rub-out-all-the-uncertainty estimates stuff, as well as using A.12 rather than fig 12 (p xxx), to try to show that IPCC ’90 overestimated current sea level rise. First off, Pielkes graph is a straight line, and the IPCC’s clearly isn’t, so he hasn’t been exact. Secondly, the IPCC graph is obviously not intended to predict our (current) present: indeed its very hard to even read the present on its scale, since we’re in the bottom left-hand corner. And of course (just like the nonsense of the temperaature predictions) Pielke has forgotten about natural variation. And also that the figure refers to BAU, which I don’t think we’re on (though its very hard to be sure, since all the numbers are compressed for such a small period).

However, there is also no obvious reason to use A.12: you may as well use fig 12 directly, which has a nice low-best-high estimate graph under BAU. Doing my best to read that for present day (1990-2008), I’d say low was 4 cm, high about 11, and best estimate 6-8 cm, 6-8 being the thickness of the line they have drawn. Subtracting a-bit-more-than 1 cm for 1990-1993, that gives a best-estimate of 5-7 cm for 2008. And RP’s obs say a-bit-more-than-4cm. So I’d say ’90 is essentially correct, and well within its error limits.

The report isn’t very explicit about how confident it is about all of this. But fig 12 is very clear about drawing in the low-best-high.


  1. #1 Nosmo

    So why not post this as a comment on Prometheus? Or at least post the last two paragraphs.

    [You mean RP doesn't read me? -W]

  2. #2 thingsbreak

    He’s desperate for pageviews, apparently not satisfied with the denier barnacles he’s managed to make a convenient home for.

    He’s trolling outrageously, lauding CA, attacking scientists for not attacking the media, attacking scientists for [allegedly] attacking the media, basically calling the establishment clause of the First Amendment undemocratic and deliberately pretending that opposition to evolution in public education is purely grassroots and not instigated and/or supported by think tanks like DI, etc.

  3. #3 Taat Laet

    As to Chinese and CTL, it sounds good since CTL is very weak with regard to its efficiency. About 45% of the original energy is lost during coal liquefaction (my own back-of-envelop calculation based on an National Energy Technology Laboratory study at

    But anyway, the Chinese cut back CTL only to keep coal for power generation, and above all production and consumption of coal in China has doubled between 2000 and 2007.

  4. #4 wottle

    I don’t get Pielke Jr.

    It seems he keeps on referencing this paper in Nature with Tim Wigley something like every three weeks or so?

    What is going on?

The site is currently under maintenance and will be back shortly. New comments have been disabled during this time, please check back soon.