The trouble with using models to prove a theory is that they can do no such thing. The only way to assess a theory scientifically is to devise tests that the theory can fail. If the theory fails the test, it is almost certainly wrong. If it passes, it is still not proven absolutely – it merely means that the theory is adequate for the circumstances of the test.
The IPCC scientists employ climate models incorporating man-made CO2 emissions to predict climate changes. Their argument is to the effect that if the predictions are approximately correct and show an expected trend when CO2 is factored in (to their models), but fail to do so when it is removed, then that “proves” the Anthropogenic Global Warming theory. AGW theory holds that man-made CO2 causes global warming, and that it will lead to a disastrous runaway greenhouse effect.
Scientists and thinkers have always used models to illustrate their theories about the universe. The models did not test the theories; they illustrated them. Yet Al Gore and the IPCC insist that the computer models provide supporting evidence for AGW. Gore goes further – he says that “the science is settled” (!) and that there is scientific consensus in favour of AGW that proves the IPCC is correct. As Penn and Teller would say, “Poppycock!” (or some other word to that effect).
Before the sixteenth century, there was almost universal scientific consensus that the earth was the centre of the universe, and that the sun, moon and all the stars revolved around it. Western astronomers believed it absolutely. Their picture was the one described by Ptolemy, a brilliant Greek scientist, astronomer and mathematician, who published his work in Egypt about 150 AD. In his model, stars were on the rim of a large outer sphere which rotated approximately once each day. The planets, the Sun, and the Moon each had their own, smaller sphere. His model was unable to account for an inconvenient truth – the paths of the sun and planets were not what one would expect from them as they orbited the earth. So he added epicycles, deferents and equants to explain the differences. Click here for a description of the added constructs.
To put it clearly, it never occurred to him to abandon the theory. Instead, he tweaked the model.
Craftsmen in Europe built elegant mechanical models and astronomical clocks based on the conceptual model of Ptolemy. The model didn’t get everything right, it left a few puzzling gaps. But using it, astronomers could make calendar and astronomical predictions that were more accurate than the present-day global temperature predictions of the IPCC computer models. Yep, it was a pretty impressive model, supported by the consensus of all of the world’s pre-eminent scientists for over a thousand years.
And one other thing. Ptolemy’s geocentric model of the universe was flat, plain wrong.
P.S.
The IPCC scientists create the computer climate models with AGW as a given premise. Their choices of the factors and parameters to include in their models, and the weightings to be given to each, are a matter of scientific controversy. And then to top it all off, the IPCC scientists themselves are the ones who choose the raw temperature data on which to base the observations, and they are also the ones who “normalise” those data. Climategate revealed the extent to which the input data for the models have been massaged. Even if modelling was appropriate as a test of the theory, how could we possibly have any faith in their results?
