Reading on climate

Debate about glob­al warm­ing is grub­by because there are so many un-acknowl­edged pri­vate agen­das run­ning just below the sur­face. Many par­tic­i­pants in the debate have some­thing to gain (if only noto­ri­ety) from their advo­ca­cy. But atten­tion to the ques­tion has pro­voked a lot of inter­est­ing research that tells us some­thing about cli­mate and some­thing about the chal­lenge of mak­ing pub­lic pol­i­cy, includ­ing mul­ti­lat­er­al col­lab­o­ra­tion which is my area of exper­tise. The only way to erase grub­bi­ness is to pay atten­tion to the data.

Here are some things I’ve been read­ing late­ly.

First, on the nature of the “con­sen­sus” that Ross Gar­naut and many oth­ers have cit­ed as the foun­da­tion of their faith (it ain’t rea­son) in IPCC-led alarm: a fas­ci­nat­ing set of sur­vey data from Denis Bray and Hans von Storch at the Ger­man Insti­tute for Coastal Research. They present the data from their very detailed 2008 mail sur­vey of more than 2600 cli­mate sci­en­tists (373 valid respons­es: 18%). The data shows that most of the respon­dents believe that cli­mate change presents a very seri­ous threat (mean 5.5/7 s.d. 1.5). But there is a sub­stan­tial left-side tail; more than a third of the respon­dents were less cer­tain than that. Bray and von Storch observe that what­ev­er “con­sen­sus” means, it is far from ‘una­nim­i­ty’:

… rather than a sin­gle group pro­claim­ing the IPCC does not rep­re­sent con­sen­sus, there are now two groups, one claim­ing the IPCC makes over­es­ti­ma­tions (a group pre­vi­ous­ly labeled skep­tics, deniers, etc.) and a rel­a­tive­ly new for­ma­tion of a group (many of whom have par­tic­i­pat­ed in the IPCC process) pro­claim­ing that IPCC tends to under­es­ti­mate some cli­mate relat­ed phe­nom­e­na.”

A sec­ond con­clu­sion emerges from look­ing at the data from anoth­er angle:

… to exam­ine the ter­mi­nol­o­gy con­cern­ing two key con­cepts in cli­mate sci­ence, name­ly “pre­dic­tions” and “pro­jec­tions”, as used among cli­mate sci­en­tists. The sur­vey data sug­gests that the IPCC ter­mi­nol­o­gy is not adopt­ed, or only loose­ly adopt­ed, by a sig­nif­i­cant minor­i­ty of sci­en­tists. Approx­i­mate­ly 29% of the sam­ple asso­ciate prob­a­ble devel­op­ments with pro­jec­tions and approx­i­mate­ly 20% of respon­dents asso­ciate pos­si­ble devel­op­ments with pre­dic­tions.”

One of the most inter­est­ing aspects of the Bray and Storch sur­vey data is the lack of con­fi­dence in cur­rent cli­mate mod­els’ sim­u­la­tion of key cli­mate para­me­ters such as rain­fall, clouds and albe­do (bely­ing the respon­dents’ over­all con­fi­dence in the IPCC risk assess­ment)..

There is more detail on this ques­tion in a sec­ond paper I’ve read late­ly. Peter Müller of the Depart­ment of Oceanog­ra­phy at the Uni­ver­si­ty of Hon­olu­lu has con­tributed a very acces­si­ble review arti­cle to the Wiley Inter­dis­ci­pli­nary Review jour­nal on Cli­mate Change enti­tled “Con­struct­ing cli­mate knowl­edge with com­put­er mod­els” that is freely avail­able. He makes a dozen points about the nature of the uncer­tain­ties incor­po­rat­ed in the cur­rent gen­er­al cir­cu­la­tion mod­els (espe­cial­ly about the math­e­mat­i­cal chal­lenges of esti­mat­ing para­me­ters for, and solv­ing, the chaot­ic Navier-Stokes flu­id dynam­ics equa­tions); about the frailty of the mod­els’ con­ti­nent-wide res­o­lu­tion; about the use of the cur­rent mod­els as sce­nar­ios rather than fore­casts; about their (lack of) cal­i­bra­tion to cur­rent con­di­tions, about the human fac­tors and polit­i­cal con­texts of any mod­el­ling etc.

Müller’s review is well worth read­ing for its expert overview and acces­si­bil­i­ty. Anoth­er excel­lent guide is con­tained in this recent arti­cle by Judith Cur­ry (the Chair of the School of Earth Sci­ences at the Geor­gia Insti­tute of Tech­nol­o­gy)

The third paper I’ve read recent­ly is an “oldie but a good­ie”. Richard Lindzen’s 1990 (!) paper: Some Cool­ness Regard­ing Glob­al Warm­ing is an acces­si­ble, short expla­na­tion of the nature of radia­tive bal­ance and the “green­house effect” (which is noth­ing like a green­house) from a well-qual­i­fied aca­d­e­m­ic who — as the paper demon­strates — has been scep­ti­cal of the alarmist the­sis on phys­i­cal grounds for two decades or more.

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