Do the math, PM

Estimates of Global Mean Sea Level changes

The Prime Minister wants to re-engage with the evidence. Good! But she is apparently unable to read the advice of her own “experts”. Or add-up:

“…Global warming will see seas rise by possibly up to a metre by the end of the century – that’s a huge risk to many parts of our country” Extract from Julia Gillard’s 4 July press conference, quoted in The Australian

Several national science authorities including CSIRO have estimated the global mean sea level (GMSL) rise since 1992—when the crucial satellite measurements began— to be approximately 3.2 mm per year. That works out at 29 cm by the year 2100; or just under one foot in the imperial scale. Not even close to a metre.

Yes, sea-level varies from place to place: but that is irrelevant to the case for a Labor/Greens coal tax. The proposed tax addresses a global emissions “problem” because there is no way to affect the local atmospheric composition or the local sea-level.

Note, incidentally, the inconvenient sideways track in graph for the past few years? Warming of the top layers of the ocean has slowed to a stop since about 2001. It may eventually resume warming because the climate is variable over multi-decade periods (ho-hum!).

Update: In Question Time, today, the PM accused the Member for Hasluck (Ken Wyatt) of asking a question about the Labor/Green coal tax in which he “made up the numbers, in order to frighten the Australian people”. Oh the irony!


  • Do the English Peter?  Shouldn’t that be `do the maths’?

    Anyway you seem to have a pretty thin grasp of the maths yourself – for starters the statement was ‘up to’, and if i’m not mistaken anything less than 1m is also ‘up to 1m’.  And past trends do not relate directly to the future, if evidence points to accelerated warming, then you would need to multiply the rate and not use it directly.

    Everyone seems to have perfect arithmetic when it comes to petrol prices or interest rates but seem to go a bit thick when it comes to science or pushing their own barrows.

  • Hi Mike,

    You and I agree on your last para 🙂

    As for “up to 1m”… On that logic it could be “up to 1km”, too. I think it would have been more reasonable of JG to have said “up to 30cm” or even, “up to 1 foot.”

    Acceleration of the sea-level rise? Where? Do you see any acceleration in the CSIRO data I referred to? The opposite seems to be true, for reasons to which I referred in the post. I believe the PM was quoting Will Steffen, who is a dedicated hyperbollist.

    As for “math”, my OED recognises the word as a 19th Century abbreviation of “mathematical” (it doesn’t recognise ‘hyperbolist’).



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