GCMs-misuse!

Len Evens len at schur.math.nwu.edu
Sun Dec 5 10:20:02 EST 1993


Someone complained recently that there were too many flames about
the spelling or grammar of postings.   It was suggested that we concentrate
on the substance of a posting rather than its form.   However, on some
occasions, grammatical and other inadequacies make it very difficult,
if not impossible, for some of us to understand the substance.   The
posting below is an example.

In article <CHJ7JL.LoK at murdoch.acc.Virginia.EDU> rjw9y at envsci.evsc.virginia.edu. (rjw9y) writes:
>i have been reviewing the scientific jounals for cliamte change
>articles and reviewing them for a fellowship over the last 2 years.  My
>concerns are that GCM output is often used inappropriately.  It is a
>real problem when one uses GCM output to estimate the "potential impact
>of global warming" on any system especially when a)precipitation
>simulations are used b) results are interpolated to a finer spatial
>grid scale.  Most probably know why those are problems however if not
>feel free to respond.  
>
>This observation is not what prompted me to write.  Instead, I recently
>had the oportunity to listen to S. Schneider talk about GCMs.  He said
>that because GCMs were parameterized after vast amounts of CO2 were
>emitted so they cant be expected to correctly simulate climate to the
>degree which would satisfy critics like myself.  An article sent to
>Nature and Science recently demonstrating the inaccuracy of GCMs to
>capture the variation in global temperature (it involved Eigenvector
>analysis) because one or more reviewers commented that it was unfair to
>evaluate GCMs in that manner.  
>
>I dont get it.  There are a myriad of articles (especially in Dr.
>Schneider's jounal-Climatic change and even in Nature) were authors use
>temp and pcp output for 2xCO2 runs and interpolate to a smaller scale
>in order to relate, for example, how fish communities in lakes of the
>Canadian Maritime Provinces will be affected in "the future".
>
>If modellers dont want the output compared to observational data how
>come they dont govern the use of their model output?  Moreover, how in
>the world do articles like these get past review?  
>
>I'm disillusioned by the obvious inconsistancies displayed here.  Where
>has scientific objectivity gone?  beleive it or not it seems that Steve
>Schneider's mentality of not bothering to seperate beliefs and bias
>from scientific work (not an exact quote, i admit but not far) has
>become widespread.  
>
>I feel the scientific literature has revealed that while GCMs have
>their usefulness and are "state of the art", they are woefully
>inadequate to predict either qualitative or quantitative climate change
>estimates yet.
>This is especially true in light of the extreme climate variations
>exhibited in proxy climate data which has been published over the last
>5 years or so.
>
>Bob Wood
>e-mail rjw9y at virginia.edu----------- i am a rational person interested
>in rational responces not a political discussion, please. 



Leonard Evens      len at math.nwu.edu      708-491-5537
Dept. of Mathematics, Northwestern Univ., Evanston, IL 60208



More information about the Ag-forst mailing list