From Tallbloke’s Talkshop

September 16, 2023 by oldbrew

The alarmist media bought it at the time, which may well have been the idea.
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A new paper from the Global Warming Policy Foundation reveals that the IPCC’s 2013 report contained a remarkable logical fallacy, says Climate Change Dispatch.

The author, Professor Norman Fenton, shows that the authors of the Summary for Policymakers claimed, with 95% certainty, that more than half of the warming observed since 1950 had been caused by man.

But as Professor Fenton explains, their logic in reaching this conclusion was fatally flawed.

“Given the observed temperature increase, and the output from their computer simulations of the climate system, the IPCC rejected the idea that less than half the warming was man-made. They said there was less than a 5% chance that this was true.”

“But they then turned this around and concluded that there was a 95% chance that more than half of observed warming was man-made.”

This is an example of what is known as the Prosecutor’s Fallacy, in which the probability of a hypothesis given certain evidence is mistakenly taken to be the same as the probability of the evidence given the hypothesis.

As Professor Fenton explains:

If an animal is a cat, there is a very high probability that it has four legs. However, if an animal has four legs, we cannot conclude that it is a cat. It’s a classic error, and is precisely what the IPCC has done.”

Source here.