Re: [asa] Level of certainty in science

From: Iain Strachan <>
Date: Thu Feb 08 2007 - 05:05:08 EST

But surely forecasting short term variations is an entirely different
field from forecasting long term trends, so it would seem that the
comparison you are making is not a fair one?


On 2/8/07, Don Winterstein <> wrote:
> On the face of it one of the more disturbing things about trust in climate
> scientists' predictions is their record or lack thereof on forecasts. We
> know how to do hindcasts, and after fiddling endlessly with them they can
> look impressive. But forecasts--if accurate--are where the payoff will be.
> How good are climate scientists at forecasting anything? To my knowledge
> they have no record.
> If so, by taking the forecast capabilities of their models seriously we'd be
> sticking our necks out for people who have essentially no record of either
> success or failure. That would make me nervous if I were betting a lot on
> their being correct.
> Don
> ----- Original Message -----
> From: PvM
> To: Don Winterstein
> Cc: asa
> Sent: Tuesday, February 06, 2007 8:48 PM
> Subject: Re: [asa] Level of certainty in science
> You are correct that skepticism about models is good. However, models
> do not exist in a vacuum but rather take existing data from the past
> and use hindcasts as well as forecasts to validate the performance. In
> addition, climate models are based on laws of physics and while they
> may miss relevant processes, climate models are well founded in
> science.
> Sure, all these models may be wrong and the earth may end up cooling
> and the scientists may look foolish, on the other hand the earth may
> actually follow the predictions and who would look foolish then?
> Science is never certain and global warming is no exception but there
> are good or even strong reasons to believe that these predictions are
> quite valid.
> <quote>For example, the Program for Climate Model Diagnosis and
> Intercomparison at Lawrence Livermore National Laboratory has been
> conducting model comparison and validation tests since 1989 (including
> the climate models used by the IPCC), and published a publicly
> available report of its research in the summer of 2004. [see
> ]</quote>
> IPCC is also involved in validation of models and I believe that most
> scientists understand that models are supplementary to other
> scientific data and cannot stand alone.
> AR4 draft also shows the hard work done here:
> * Executive Summary
> * Advances in Modeling
> * Evaluation of Contemporary Climate as Simulated by Coupled Global
> Models
> * Evaluation of Large Scale Climate Variability as Simulated by
> Coupled Global Models
> * Evaluation of the Key Relevant Processes as Simulated by Coupled
> Global Models
> * Model Simulations of Extremes
> * Climate Sensitivity
> * Evaluation of Model Simulations of Thresholds and Abrupt Events
> * Representing the Global System With Simpler Models
> <quote>There is considerable confidence that climate models provide
> plausible quantitative estimates of future climate change,
> particularly at continental scales and above. Confidence in these
> estimates is higher for some climate variables (e.g. temperature)
> than for others (e.g. precipitation). This confidence comes from the
> foundation of the models in accepted physical principles and from
> their ability to reproduce observed features of recent climate (see
> Chapters 8, 9) and past climate changes (see Chapter 6). In this
> summary we highlight areas of progress since the TAR:
> </quote>
> On 2/6/07, Don Winterstein <> wrote:
> >
> >
> >
> > Pim Van Meurs wrote: "What is so scary about science being correct once
> > again? If one
> > believes this to be scary, imagine how scary it could be when
> > Christians, as Augustine pointed out, are observed spouting scientific
> > nonsense?"
> >
> > Who's got more to lose here? The climate data may be fairly firm, but the
> > models, from which scientists make predictions, are likely much less
> > trustworthy. They're Earth science models, after all. If Earth starts
> > cooling within a few decades--as it's been known to do, climate scientists
> > and other scientists by association will lose credibility for a long time
> to
> > come.

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- Italian Proverb
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Received on Thu Feb 8 05:07:14 2007

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