From: Eleanor McHugh <eleanor@...>
Date: 2009-04-23T03:52:23+09:00
Subject: Re: Goodbye Ruby - Hello Earth

On 22 Apr 2009, at 14:35, Phlip wrote:
> Eleanor McHugh wrote:
>> My main criticism of climate science's attempts to model global   
>> warming is that it's fundamentally flawed in its methodology. The   
>> climate is a chaotic non-linear system and hence the only way to  
>> make  accurate predictions is to understand its exact starting  
>> conditions.
>
> The _weather_ is chaotic. The _climate_ is the walking average,  
> beneath the turbulence. The point of the Butterfly Effect aphorism  
> is you _can't_ predict whether the butterfly's wings flapping in  
> Africa will create a hurricane in the Atlantic, even if you _did_  
> know how its wings flapped in microscopic detail.

With the starting conditions and the correct model a chaotic system  
can be predicted because it is fundamentally deterministic.
With the starting conditions and a set of experimental data the model  
is derivable from observation, given sufficient observations.
Without the starting conditions, all bets are off.

> However, you can predict trends over time, and you can predict the  
> effect of forcing (such as more sunspots, or more CO2) on those  
> trends. For example, Katrina occurred at the peak of a decadal cycle  
> in hurricane activity. That doesn't mean CO2 didn't have a role...

But conversely it doesn't mean that it did either, or that if it did  
its role was the significant factor.

>> Instead researchers take patchy historical data over a brief   
>> geological period and feed that into incredibly complex climate  
>> models  to produce predictions.
>
> That's the prediction phase of the experiment. Then they confirm  
> their predictions by correlating them to historical data, such as  
> ice cores in glaciers containing the predicted amounts of certain  
> chemicals at certain depths.

If I build a model based upon data for a given timeframe and I make  
that model capable of predicting other results for that timeframe I  
have an intellectual curiosity. It's only when I can apply that model  
globally and still achieve a significant correlation between data and  
results that I can promote the underlying hypothesis to the status of  
a theory. Looking in from the outside, climate science still appears  
to have a long way to go before it achieves that.

This wouldn't matter except that people seem desperate to use these  
models to drive public policy for purposes which could much better be  
argued on non-apocalyptic grounds.

>> Am I the only one reminded of Ptolemy's model of the heavens? A   
>> stunning intellectual achievement, but as Copernicus demonstrated  
>> so  effectively, a complete fiction which prevented astronomy from   
>> progressing for a good fourteen hundred years.
>
> You have both the history and details wrong. Copernicus did not  
> _demonstrate_ anything - he simply published the alternate view,  
> which had already existed. And (the ghost of Carl Sagan  
> notwithstanding), Ptolemaic models did not "prevent astronomy from  
> progressing". You could still predict, over time, where Mars and  
> Jupiter would appear in the skies. That's as old as Astrology.

What Copernicus advanced was a model of orbital motion which placed  
the Sun at the centre of the cosmos as opposed to the Earth, with the  
distance between the two considered insignificant to the overall size  
of the cosmos. It's true that he wasn't the first to posit a sun- 
centred model, but to the best of my knowledge he was the first to  
accompany it with a mathematical model of the orbital motion involved.  
It was this mathematical model which allowed Astronomy and Physics to  
develop into the sciences we know today, although arguably it is just  
one of a set of correlated historical events including the fall of  
Constantinople and the expulsion of the Moorish and Jewish communities  
from Spain.

Anyway, I stand by my argument, various rabbit holes, omissions and  
over-simplifications not withstanding.


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason