Posts Tagged ‘Model error’

The IPCC 95% trick: Increase the uncertainty to increase the certainty

October 17, 2013

Increasing the uncertainty in a statement to make the statement more certain to be applicable is an old trick of rhetoric. Every politician knows how to use that in a speech. It is a schoolboy’s natural defense when being hauled up for some wrongdoing. It is especially useful when caught in a lie. It is the technique beloved of defense lawyers in TV dramas. Salesmen are experts at this. It is standard practice in scientific publications when experimental data does not fit the original hypothesis.

Modify the original statement (the lie) to be less certain in the lie, so as to be more certain that the statement could be true. Widen the original hypothesis to encompass the actual data. Increase the spread of the deviating model results to be able to include the real data within the error envelope.

  • “I didn’t say he did it. I said somebody like him could have done it”
  • “Did you start the fight?” >>> “He hit me back first”.
  • “The data do not match your hypothesis” >>> “The data are not inconsistent with the improved hypothesis”
  • “Your market share has reduced” >>> “On the contrary, our market share of those we sell to has increased!” (Note -this is an old one used by salesmen to con “green” managers with reports of a 100% market share!!)

And it is a trick that is not foreign to the IPCC  – “we have a 95% certainty that the less reliable (= improved) models are correct”. Or in the case of the Cook consensus “97% of everybody believes that climate does change”.

A more rigorous treatment of the IPCC trick is carried out by Climate Audit and Roy Spencer among others but this is my simplified explanation for schoolboys and Modern Environ-mentalists.

The IPCC Trick

The IPCC Trick

The real comparison between climate models and global temperatures is below:

Climate Models and Reality

Climate Models and Reality

With the error in climate models increased to infinity, the IPCC could even reach 100% certainty. As it is the IPCC is 95% certain that it is warming – or not!


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