RE: [asa] Freeman Dyson on Climate Change

The Navier-Stokes equations are nonlinear, which have no known analytic
solutions. Therefore, one uses approximations to solve them, which
effects are no always clear to understand. Of course, I am not sure if
one knows all the physics that may be contained in the Navier-Stokes
equations. For instance, can it explain turbulence?

Moorad

-----Original Message-----
From: PvM [mailto:pvm.pandas@gmail.com]
Sent: Tuesday, April 17, 2007 12:31 PM
To: Alexanian, Moorad
Cc: wdwllace@sympatico.ca; asa@calvin.edu; Glenn Morton
Subject: Re: [asa] Freeman Dyson on Climate Change

What kind of approximations are we talking about here and how would
they impact the solution? Hand waving surely seems insufficient to
reject models. Especially when different models all come to the same
solutions.

On 4/17/07, Alexanian, Moorad <alexanian@uncw.edu> wrote:
> It often happens that one may base the physics of a process on sound
physical models; however, in order to solve such basic equations, one
often makes all sorts of approximations. Therefore, one is never sure
what the sources of the resulting solutions are, whether they are in the
basic physics or in the approximations themselves. This is the case when
using the Navier-Stokes equations. Freeman Dyson is an outstanding
physicist.
>
>
>
> Moorad
>
> ________________________________
>
> From: asa-owner@lists.calvin.edu on behalf of PvM
> Sent: Mon 4/16/2007 10:19 PM
> To: wdwllace@sympatico.ca
> Cc: asa@calvin.edu; Glenn Morton
> Subject: Re: [asa] Freeman Dyson on Climate Change
>
>
>
> That just pure nonsense. They are hardly unreliable. In fact they are
> based on Navier Stokes equations, which are the basic equation of
> motion. Yes there are some parameters that require some tuning because
> they capture small scale effects not adequately captured by the grid.
>
> This is such nonsense, who is this Dyson that he can get away with
> such nonsense?
>
> On 4/16/07, Dave Wallace <wdwllace@sympatico.ca> wrote:
> > From an Interview with Dyson reproduced on UnC
> >
http://www.uncommondescent.com/intelligent-design/interview-with-freeman
-dyson/#more-2258
> >
> > <quote>
> > Concerning the climate models, I know enough of the details to be
sure
> > that they are unreliable. They are full of fudge factors that are
fitted
> > to the existing climate, so the models more or less agree with the
> > observed data. But there is no reason to believe that the same fudge
> > factors would give the right behavior in a world with different
> > chemistry, for example in a world with increased CO2 in the
atmosphere.
> > </quote> Dyson
> >
> > Essentially he is talking about curve fitting by adjusting the fudge
> > factors which is an issue I raised a while back. This is the kind
of
> > reason that I am in favor of actions that address smog, peak fossil
fuel
> > and greenhouse gases, at least as a strong initial priority.
> >
> > For example few people will deny that smog is caused by burning
fossil
> > fuel. Even if Glenn is wrong by a few decades in terms of peak oil,
> > fossil fuel is limited especially considering the increasing demand
from
> > China and India. Pushing intercity trucks and short haul air
flights to
> > use rail, seems to be a big win for all three concerns at least
north of
> > the 49th parallel but I would assume in the US as well. Heating and
> > insulation in houses is also another similar win, especially wrt
older
> > or poorly built houses. When the temperature goes to -30F with a
high
> > of -20F, I feel cold spots very readily in our house even though we
have
> > been making improvements over the years.
> >
> > From
> >
http://www.railcan.ca/documents/publications/2006_10_24_DOH_Sustainable_
en.pdf
> > <quote>
> > Per passenger or tonne, rail generates only one-fifth
> > the greenhouse gas emissions of trucking, one-quarter
> > the emissions of urban automobiles, and one-third the
> > emissions of inter-city automobiles or planes in densely
> > populated corridors.
> > In Canada, approximately one-quarter of national greenhouse
> > gas (GHG) emissions are from the transportation
> > sector. Transport emissions actually rose 30 per cent between
> > 1990 and 2004 to 190 megatonnes, the most recent
> > data available across all transport modes, with more than
> > half of the increase a result of road freight.
> > </quote>
> >
> > (A tonne is a metric ton, 2200lbs appx.)
> >
> > Of course the models could be wrong the other way and be
underestimating
> > the impact of CO2 and eventually positive feedbacks could kick in
like
> > melting of the permafrost or the icecaps.
> >
> > Dave W
> >
> >
> > To unsubscribe, send a message to majordomo@calvin.edu with
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> >
>
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>

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Received on Tue Apr 17 13:15:13 2007