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Andrew Orlowski: Tell us we’re all doomed, MPs beg climate scientists
Andrew Orlowski of the Register has written a lucid account of the Climate Change Committee hearing on the IPCC AR5 climate report. I’ve excerpted a highlight below, but do go and read the whole thing, it’s an excellent summary, and entertainingly written.
Excerpt from: Tell us we’re all doomed, MPs beg climate scientists
by Andrew Orlowski – The register 31-1-14
Lindzen tried to explain that the temperature hiatus really ought cause some soul-searching amongst the establishment’s climate modellers.
The longer this goes on the harder it will be to support a high climate sensitivity. It wasn’t predicted.
Nic Lewis’ own work concludes that CO2 has an impact on the climate – just one that’s lower than the scientific establishment’s most likely impact. It takes more accurate recent observational estimates of aerosols into account. He told MPs that the IPCC’s estimate of greenhouse gas climate sensitivity – the climate system’s response to an increase in (mainly) CO2 – is about three times higher than it should be.
This indicates the models are not to be relied on.
As he explains in his lucid written evidence for the enquiry (written for a layman with a basic grasp of maths) and reminded MPs, Lewis uses a different application of Bayesian maths.
“Most of the studies, but not all of them, use a Subjective Bayesian approach. Some use an Objective Bayesian approach, and some use non-Bayesian statistics. The Objective and non-Bayesian studies give very much the same answer. The Subjectives produces results depending on what you put in, as the Uniform Prior you choose bumps up the higher end,” said Lewis.
Some use an Expert Prior using older observational data, “and that has dominated their results.”
“Their studies are not statistically sound,” he added. “I don’t think there is the statistical expertise in Bayesian theory in climate science that there ought to be.”
How come the IPCC hadn’t based its conclusions on the most recent data, asked Peter Lilley MP (Con, Hitchin & Harpenden).
“By the time they realised the observations and models disagreed – so much of the report is built around model simulations – they couldn’t really write conclusions that say the models were wrong,” said Lewis.
Lindzen argued that the models failed to model accurately.
No models at present do an acceptable job on decadal oscillations, or multidecadal oscillations, and there may be longer periods we don’t know about.
MPs asked if it was possible to believe the models if ECS (equilibrium climate sensitivity) was closer to Lewis’ estimate than to the IPCC estimates.
“Is it possible to play it down and still be worried by anthropogenic global warming?” asked one MP.
”Not really,” said Lewis.
Source: http://tallbloke.wordpress.com/2014/01/31/andrew-orlowski-tell-us-were-all-doomed-mps-beg-climate-scientists/
