- they reported the value for climate sensitivity (the eventual warming from doubling CO2) as the IPCC projection for warming by 2100
- they reported the maximum sea level rise for scenario B2 (43 cm) as the maximum rise, ignoring the other scenarios and the fact that the rise does not include any increase from accelerating ice flow.
The false reports generated erroneous commentary like this nonsense from Iain Murray:
I wrote earlier about how the IPCC has quietly changed its definition of its projected temperature rises to include all pre-industrial warming, not just warming from 1990 onwards. Our best information has it that the IPCC calculates that 0.8 degrees centigrade has already occurred.
Subtracting that 0.8 from the projected temperature rises in the Fourth Assessment Report gives us a projected temperature rise this century of just 1.2 to 3.7 degrees centigrade. It also lowers the “best guess” for temperature rise to 2.2 degrees centigrade. This compares to the Third Assessment Report range of 1.4 to 5.8 degrees. Yes, the IPCC has actually lowered the lower band of its projections, despite all the hype that it has raised it upwards.
This is badly wrong. Murray took the range for climate sensitivity and subtracted 0.8 for warming so far. The resulting number is the amount of warming still to eventually come if we stabilise CO2 at double pre-industrial values, provided we assume that all of the warming since 1900 is man-made (something that Murray would never admit). It’s not the IPCC projected warming by 2100, which is still measured relative to 1990. (Well, actually in AR4 it’s relative to the average for 1980-1999). The CEI is advertising Murray as an “expert” willing to comment on AR4.
And then there’s Andrew Bolt. Bolt cited the false number for sea level rise in his column that got zero out of ten for accuracy. I told him that it was wrong, so what does he do? A few hours before the new report is released he writes this
Tim Lambert writes to me on October 6:
The only substantive objection you have raised (actually false – AB) [actually true – TL] is to claim that I’m not up to date on the new IPCC report. Actually I am. I’ve read it and you haven’t. It does not predict sea level rises of 14-43cm. You seem to be relying on an inaccurate story in the Australian. The new IPCC report has similar numbers for sea level rise as the previous one.
New Scientist (among many others) now report on the eve of today’s release of that report:
Similarly, the new report is believed to predict that sea-levels will rise by between 28 centimetres and 43 cm cm by 2100, compared with the 2001 prediction of between 9 cm and 88 cm.
Question: What report was Lambert reading? Or did he make that bit up, too?
Bolt just couldn’t wait a few more hours till the report was released so he compounded his error by giving another false number for sea level rise. And if you thought that Bolt would admit to being wrong when the report was released, you are unfamiliar with Andrew Bolt. When I told him that the range was 18cm-59cm he responded with:
First, I’d still like to know why you claimed to have read a draft report that predicted a rise in sea levels similar to the rise predicted in the 2001 report – ie a rise of as much as 88cm, when in fact even by your admission it now cuts that maximum to 59cm.
I didn’t say the numbers were the same, merely similar. And the comparison is 59cm + extra from accelerating ice flows versus 88cm. [Update: Some people couldn’t understand this, so more here.]
Second, I note you seize on the most extreme of the six scenarios suggested by climate models – a scenario with the “best estimate” of a temperature rise this century of 4 degrees, when the average rise suggested by the six scenarios is just 2.5 degrees. Smack in the middle of those scenarios is B2, which indeed suggests a sea level rise of between 20 and 43 cm, which was apparently the one leaked to the various journalists whose reports I quoted.
Of course I didn’t seize on the worst case scenario. The range is the lowest number from the best case to the highest number from the worst case. And it’s not true that just the B2 scenario was leaked — the whole draft report was, and the journalists misunderstood it.