BJORN LOMBORG GETS LAMBERTED

Tim Lambert was the other day caught fudging sea level rise figures. Not being one to admit his errors, Lambert refused to admit he got it wrong. Emboldened by his successful stonewalling (his gullible readers didn't question his desperate maneuvering) he takes the sea level rise fudging one step further in attempting to embarrass Bjørn Lomborg.

Lambert contended that he was correct in describing the original 88 cm IPCC sea level rise forecast as similar to the latest 59 cm IPCC sea level rise figure because additional water had to be accounted for, quoting from AR4 (my bold):

Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet flow, because a basis in published literature is lacking. The projections include a contribution due to increased ice flow from Greenland and Antarctica at the rates observed for 1993-2003, but these flow rates could increase or decrease in the future. For example, if this contribution were to grow linearly with global average temperature change, the upper ranges of sea level rise for SRES scenarios shown in Table SPM-2 would increase by 0.1 m to 0.2 m. Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.

Lambert ignored the uncertainty described in the excerpt, picked out the top-of-the-range 20 cm figure and added it to the 59 cm forecast to come up with a total forecast sea level rise of 79 cm. He says 79 is similar to 88. But no matter how you look at it this is all a little bit tricky; the 10 to 20 cm contribution is highly qualified and could in reality be more or less. Thus the correct sea level rise figure is 59 cm plus an unknown amount. Now I don't know about you, but if a plumber quoted a job as costing $59 plus an unknown additional amount (but likely an extra $10 to $20), I'd probably look for a different plumber.

Anyway, Lambert is now applying the same dubious thinking to an article by Bjørn Lomborg:

Bjorn Lomborg makes the (by now traditional) claim that the new IPCC report has significantly reduced the estimates of projected sea level rises.

Six years ago, it anticipated ocean levels would be 48.5 centimeters higher than they are currently. In this year's report, the estimated rise is 38.5 centimeters on average.

But the 38.5 number Lomborg presents does not include increases from accelerating ice flows. About these, the report says:

For example, if this contribution were to grow linearly with global average temperature change, the upper ranges of sea level rise for SRES scenarios shown in Table SPM-2 would increase by 0.1 m to 0.2 m. Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.

Lambert has omitted the crucial first two uncertainty sentences from the report excerpt:

Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet flow, because a basis in published literature is lacking. The projections include a contribution due to increased ice flow from Greenland and Antarctica at the rates observed for 1993-2003, but these flow rates could increase or decrease in the future.

Lambert wants Lomborg to say the new report predicts sea level will rise rise by 38.5 cm plus 10 to 20 cm, at least equaling, and probably exceeding, the previously forecast 48.5 cm rise. This is ludicrous since the 10 to 20 cm range is at best a guess. It would perhaps have been more accurate for Lomborg to describe the reports forecast rise as 38.5 cm plus an unknown amount but that still leaves 38.5 cm as the only cited figure.

If the science backing up Lambert is sound, why does he resort to such trickery? Regardless, Lambert's your man if you want political points scoring through subtle manipulation; if you're after science you need to look someplace else.