More fun with numbers

by Iain Murray on February 1, 2007

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 occured.

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.

Interestingly, prominent “skeptic” Pat Michaels has been saying for years that the way the models behave coupled with real world data suggests a best guess of 1.7 degrees temperature rise this century. Pat’s projection is now clearly towards the middle of the consensus. In other words, the IPCC has moved towards the skeptical position, so much so that the IPCC’s lower bound for temperature rise is now a full half a degree less than prominent skeptics have been saying, while the skeptics’ best guess is only half a degree less than the consensus best guess. This is chump change compared with previous disparities.

No wonder the alarmists are in a tizzy.

UPDATE:  The Reuters correspondent confused climate sensitivity with temperature projections.  That means that this post is, well, just plain wrong.  I should have spotted that.  Sorry.

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