Re: OT: interesting global warming quote found elsewhwere

On Jul 26, 2:52 am, James Arthur <bogusabd...@xxxxxxxxxxx> wrote:
John Larkin wrote:
Thare are serious claims that the models have been fudges to work
backwards. That's not unreasonable, but the parameters are
extraordinarily sensitive, so making a model back-track well doesn't
mean it's predictive; it just means it's tweaked.

It's like the stock market and the many, many "models" developed
to profit from it. They all go bust.

"Past performance is not an indication of future results."
    --Wall Street disclaimer

And this is for a closed, mildly chaotic system with a
well-established long-term upward trend, with a limited
set of variables, all available with great precision,
in real-time. The entire system is "instrumented,"
documented, and logged on-line.

Sure, but any predictive model of the stock market feeds information
to the participants in the market, who proceed to try and exploit,
thus destroying the model's predictive capacity.

The climate - as recorded in the ice-core data and the geological
record - tends to bounce around within fairly stable bounds, limited
by the heat coing in from the sun and the heat radiated by earth's
atmosphere.

Tweak and tweak and tweak, and they can replicate history
with greater and greater precision--after the fact.  But
predict the future?  Not a one.

You are right about the stock market. Climate models - as opposed to
weather predictions - can do better, albeit within relatively broad
bands of possibilities.

<snip>

At bottom, the climate and the atmosphere are controlled by
life itself; the carbon we burn is carbon dredged from the
air and buried by ancient plants.  Plants draw carbon from
the air until it becomes too sparse and too cool for them
to thrive.

You forget the geological processes that turn buried carbonate back
into the carbon dioxide that comes out of volcanoes - our mining and
drilling is returning a lot more carbon dioxide to the atmosphere than
today's collection of active volcanoes, but volcanic activity isn't
all that predictable either. Make the planet cold enough - google
iceball earth - and the volcanoes will eventually restore the carbon
dioxide greenhouse regime.

There's your long-term negative feedback.

Some of it. And it constitutes exactly the kind of climate modelling
whose predictive value you've just denied.

--
Bill Sloman, Nijmegen
.

Relevant Pages

  • Re: OT: interesting global warming quote found elsewhwere
    ... weather predictions - can do better, ... the carbon we burn is carbon dredged from the ... today's collection of active volcanoes, ...   o the plants go nuts, gobble all the precious CO2, driving ...
    (sci.electronics.design)
  • Re: OT: interesting global warming quote found elsewhwere
    ... weather predictions - can do better, ... the carbon we burn is carbon dredged from the ... drilling is returning a lot more carbon dioxide to the atmosphere than ... today's collection of active volcanoes, ...
    (sci.electronics.design)
  • Re: OT: something for Sloman to think about :-)
    ... Sloman errs in saying the predictions are "scientific" but in fact they are ... The anthropogenic CO2 lies on top of a variable natural CO2 flux.. ... fossil carbon which is low in carbon-13 and contains no carbon-14. ... oceanic feedbacks and biological feedbacks (slow but ...
    (sci.electronics.design)
  • Re: How low will the stock market go ?
    ... I avoid stock market predictions for the same reason most people do. ... make a profit if it were not for the American taxpayer and consumer? ... We can't hang the corporations, ...
    (soc.retirement)
  • Re: Thats It
    ... To make market predictions, you get a bunch of time series of, say, P/E ... for the stock market"? ... I DID configure a neural network to make ...
    (misc.invest.stocks)
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