Unequivocal Equivocation

If you can't prove your theory, change the definition of proof.

Willis Eschenbach writes an open letter to Dr. Kevin Trenbert taking him to task for attempting to redfine the requirements of a scientific theory:

I would like to take as my text the following quote from the recent paper (PDF, 270k also on web here) by Dr. Kevin Trenberth:

Given that global warming is “unequivocal”, to quote the 2007 IPCC report, the null hypothesis should now be reversed, thereby placing the burden of proof on showing that there is no human influence [on the climate].

Figure 1. The game of Monopoly’s “Community Chest” card that was randomly drawn by Dr. Kevin Trenberth. Some guys are just lucky, I guess.

The “null hypothesis” in science is the condition that would result if what you are trying to establish is not true. For example, if your hypothesis is that air pressure affects plant growth rates, the null hypothesis is that air pressure has no effect on plant growth rates. Once you have both hypotheses, then you can see which hypothesis is supported by the evidence.

In climate science, the AGW hypothesis states that human GHG emissions significantly affect the climate. As such, the null hypothesis is that human GHG emissions do not significantly affect the climate, that the climate variations are the result of natural processes. This null hypothesis is what Doctor T wants to reverse.
As Steve McIntyre has often commented, with these folks you really have to keep your eye on the pea under the walnut shell. These folks seem to have sub-specialties in the “three-card monte” sub-species of science. Did you notice when the pea went from under one walnut shell to another in Dr. T’s quotation above? Take another look at it.

The first part of Dr. T’s statement is true. There is general scientific agreement that the globe has been warming, in fits and starts of course, for the last three centuries or so. And since it has been thusly warming for centuries, the obvious null hypothesis would have to be that the half-degree of warming we experienced in the 20th century was a continuation of some long-term ongoing natural trend.

But that’s not what Dr. Trenberth is doing here. Keep your eye on the pea. He has smoothly segued from the IPCC saying “global warming is ‘unequivocal’”, which is true, and stitched that idea so cleverly onto another idea, ‘and thus humans affect the climate’, that you can’t even see the seam.

The pea is already under the other walnut shell. He is implying that the IPCC says that scientists have “unequivocally” shown that humans are the cause of weather ills, and if I don’t take that as an article of faith, it’s my job to prove that we are not the cause of floods in Brisbane.
Now, lest you think that the IPCC actually did mean that ‘humans are the cause’ when they said (in his words) that ‘global warming was “unequivocal”‘, here’s their full statement from the IPCC Fourth Assessment Report Summary For Policymakers (2007)  (PDF, 3.7 MB):

Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level (see Figure SPM-3).

Despite the vagueness of a lack of a timeframe, that is generally true, but it says nothing about humans being the cause. So he is totally misrepresenting the IPCC findings (which he helped write, remember, so it’s not a misunderstanding) to advance his argument. The IPCC said nothing like what he is implying.

Gotta love the style, though, simply proclaiming by imperial fiat that his side is the winner in one of the longest-running modern scientific debates. And his only proffered “evidence” for this claim? It is the unequivocal fact that Phil Jones and Michael Mann and Caspar Amman and Gene Wahl and the other good old boys of the IPCC all agree with him. That is to say, Dr. T’s justification for reversing the null hypothesis is that the IPCC report that Dr. T helped write agrees with Dr. T. That’s recursive enough to make Ouroboros weep in envy …

And the IPCC not only says it’s true, it’s “unequivocal”. Just plain truth wouldn’t be scientific enough for those guys, I guess. Instead, it is “unequivocal” truth. Here’s what “unequivocal” means (emphasis mine):

unequivocal: adjective:  admitting of no doubt or misunderstanding; having only one meaning or interpretation and leading to only one conclusion (“Unequivocal evidence”)

Notice how well crafted Dr. T’s sentence is. After bringing in “global warming”, he introduces the word “unequivocal”, meaning we can only draw one conclusion. Then in the second half of the sentence, he falsely attaches that “unequivocal” certainty of conclusion to his own curious conclusion, that the normal rules of science should be reversed for the benefit of … … well, not to put too fine a point on it, he’s claiming that normal scientific rules should be reversed for the benefit of Dr. Kevin Trenberth and the IPCC and those he supports. Probably just a coincidence, though.

For Dr. Trenberth to call for the usual null hypothesis (which is that what we observe in nature is, you know, natural) to be reversed, citing as his evidence the IPCC statement that the earth is actually warming, is nonsense. However, it is not meaningless nonsense. It is pernicious, insidious, and dangerous nonsense. He wants us to spend billions of dollars based on this level of thinking, and he has cleverly conflated two ideas to push his agenda.

I understand that Dr. T has a scientific hypothesis. This hypothesis, generally called the “AGW hypothesis”, is that if greenhouse gases (GHGs)  go up, the temperature must follow, and nothing else matters. The hypothesis is that the GHGs are the master thermostat for the globe, everything else just averages out in the long run, nothing could possibly affect the long-term climate but GHGs, nothing to see here, folks, move along. No other forcings, feedbacks, or hypotheses need apply. GHGs rule, OK?

Which is an interesting hypothesis, but it is woefully short of either theoretical or observational support. In part, of course, this is because the AGW hypothesis provides almost nothing in the way of a statement or a prediction which can be falsified. This difficulty in falsification of the hypothesis, while perhaps attractive to the proponents of the hypothesis, inevitably implies a corresponding difficulty in verification or support of the hypothesis.

Read the rest here.