The illogic of blaming man

The physi­cist Free­man Dyson, in a slight­ly tetchy email exchange with the Sci­ence Edi­tor of the Inde­pen­dent news paper, argues that the IPCC’s alarm about warmer tem­per­a­tures is due to dog­mat­ic over­con­fi­dence in the pro­jec­tions of some poor mod­els.

My impres­sion is that the experts are delud­ed because they have been study­ing the details of cli­mate mod­els for 30 years and they come to believe the mod­els are real. After 30 years they lose the abil­i­ty to think out­side the mod­els. And it is nor­mal for experts in a nar­row area to think alike and devel­op a set­tled dog­ma. The dog­ma is some­times right and some­times wrong. In astron­o­my this hap­pens all the time, and it is great fun to see new obser­va­tions that prove the old dog­mas wrong. Unfor­tu­nate­ly things are dif­fer­ent in cli­mate sci­ence because the argu­ments have become heav­i­ly politi­cised. ” Extract from The Inde­pen­dent

No doubt, cli­mate mod­el­ling will improve as knowl­edge of cli­mate change improves. But I can agree with Dyson that the IPCC’s con­clu­sions are unsound with­out eval­u­at­ing their mod­el­ling skills because their log­ic is faulty and can be reme­died only by an untruth.

In my course on Trade Research Meth­ods (part of the Mas­ters in Inter­na­tion­al Trade and Devel­op­ment, at the Uni­ver­si­ty of Ade­laide) I say that a researcher must be able to pre­cis com­plex or detailed argu­ments because, among oth­er things, a pre­cis helps focus atten­tion on the main premis­es of an argu­ment, expos­ing its log­i­cal struc­ture and, some­times, faults.

One exam­ple I offer is a four-sen­tence pre­cis is of the volu­mi­nous “Syn­the­sis” of the IPCC’s Fourth Assess­ment Report that runs to more than sev­en­ty pages of dense prose and illus­tra­tions. I argue that the sum­ma­ry expos­es a log­i­cal gap in the IPCC’s argu­ment that would have to be reme­died by putting the word “all” (or even “all impor­tant”) at the front of the sec­ond sen­tence of the sec­ond item. But then, this would make this premise untrue and the con­clu­sion unsound, despite the valid­i­ty of the revised argu­ment.

  • There has been a sig­nif­i­cant rise in the glob­al aver­age tem­per­a­ture. (Sec­tion 1.1 of AR4 Syn­the­sis Report)
  • It is almost cer­tain that this tem­per­a­ture rise has been caused by the actions of mankind. Oth­er sug­gest­ed caus­es have been sub­ject to sci­en­tif­ic eval­u­a­tion and found to be either non-exis­tent or insuf­fi­cient. (Sec­tion 2.2)
  • Glob­al tem­per­a­ture increas­es of 2 — 4 deg. C. will have many unde­sir­able con­se­quences, which increase in seri­ous­ness with increas­ing tem­per­a­ture ris­es. (Sec­tion 3.3)

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