Saturday, July 09, 2011

A fat tale
...Nic Lewis, the indefatigable mathematical sleuth who helped expose the mistakes in a paper about Antarctic temperature trends has been looking at how the IPCC estimates climate sensitivity -- that is, the warming expected for a doubling of CO2. He finds that the one study that estimated sensitivity entirely from experimental data -- Forster and Gregory 2006 -- was distoted by the IPCC when it came to present their results. The distortion was the imposition of a Bayesian "uniform prior" in a way that statisticians say is wholly inappropriate, because it effectively assumes a priori that strong warming is more probable than it is. Yet you don't even have to know that the use is inappropriate to know that it's inappropriate to take a published result and alter the graph from it, adding an obscure footnote to say you have done so. A published result is a published result.

The effect was to fatten the tail of the graph, making a warming of more than 2C look much more probable....

There has been no global warming since 1998
...No global warming since 1998? Simple. All you’ve got to do – as Kaufmann et al have done – is apply the Even Though We’re Wrong We’re Right Panacea Get-Out Formula. In this instance the ETWWWRPGOF (as it’s snappily known) involves Blaming The Chinese. Yep, it turns out all that pollution that Chinese are pumping into the air thanks to their unhealthy obsession with economic growth and giving better lives to their children is actually counteracting the effects of Man Made Global Warming....

...As indeed might you and I be. For years the Warmists have been telling us that they’re so sure of their computer models that they know, they just know, that CO2 has a forcing effect on global temperatures and that combined with positive feedbacks this is going to cause catastrophic warming. And now they’re saying, without a blush, “Well all right, some of those feedbacks might actually be negative and, er, completely cancel out the terrifying thing we were telling you to worry about. But don’t stop worrying, for God’s sake. Whatever is happening is still worrying, very worrying. And if you give us a bit more time we’ll come up with a paper explaining just why it’s worrying.”...