[LINK] the weather makers
Alan L Tyree
alan at austlii.edu.au
Mon Apr 9 15:44:18 EST 2007
On Mon, 9 Apr 2007 06:48:22 +0200
Kim Holburn <kim.holburn at gmail.com> wrote:
> On 2007/Apr/08, at 11:52 PM, Alan L Tyree wrote:
> > I would like to pick up on Stewart's point of computer modelling. I
> > don't know the state of "verification" of these models. Most
> > predictions are for 50 or more years into the future. I would be far
> > more convinced if the models could be verified in one simple way:
> > plug in the data from 1900. Does the model predict the 1940-1970
> > cooling? Does it predict the remainder of the century?
> I watched an Attenborough show which showed the Hadley Centre which
> Flannery also talks about. I don't think you can talk about it like
> that. It's nowhere as accurate as that. They can get a very, very
> rough model of the last century or two. They were showing the
> results of modelling to demonstrate that unless they factor in man-
> made CO2 their models are wildly out from 1970 on.
That is my impression as well. They should, of course, factor in CO2,
man made and natural. And whatever else it takes.
But big political decisions are being taken on 50 year predictions. If
it isn't "as acurate as that", then why do we think it is accurate for
the next 50 years.
It's not enough to say that the trend is right. If the models are out
by 30 or 40 or more years, then that is important to know. It makes a
difference to our rational response.
> > We are talking **major** disruption to follow the "Precautionary
> > Principle". Most of the adverse disruption will be felt by poorer
> > nations and people (because it always is). We owe it to those
> > people to
> > be sure of what it happening.
> > And, as Stewart said, the predictions about sea levels and all the
> > rest
> > are removed once again from the basic facts.
> > When was the last time that you heard anything good about global
> > warming? Longer growing seasons? Higher CO2 levels promoting faster
> > plant growth?
> Lots. A small increase in warming increases some kinds of
> agricultural outputs in some countries. More than than about 2
> degrees and the situation gets worse and it's different for each
> country and often for different parts of each country.
> If it were simply a small change in temperature it might all be fine
> but an increase in temperature combined with a reduced amount of
> rain like they have had in the sahel region of Africa it is not so
> good for agriculture, or people.
> Kim Holburn
> IT Network & Security Consultant
> Ph: +39 06 855 4294 M: +39 3494957443
> mailto:kim at holburn.net aim://kimholburn
> skype://kholburn - PGP Public Key on request
> Democracy imposed from without is the severest form of tyranny.
> -- Lloyd Biggle, Jr. Analog, Apr 1961
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