Michael Tobis wrote
In any case one can easily examine temperature series on other planets
for a comparable temporal signature. If there were anything to this
we'd see the same thing on some of the solid planets or larger moons,
wouldn't we?
I don't want to sound like a denialist, because I'm not, but there has
been mechanisms proposed which for what I can see is worth
investigating - The theory that Milankovich cycles are triggered by
100kyear cyclical changes in magnetism. The mechanism assumes that the
way the solar and earth magnetic fields interact cause increased global
cloud cover. The only "evidence" is that there is a 100kyear cycle in
magnetism and a 100kyear cycle in climate, while the other proposed
forcing mechanisms for 100kyear cycles would make more sense if it was
a different length cycle. I don't think this makes CO2 any less a
"forcer" of recent climate change, but should spur us to study the link
between magnetic fields and cloud formation. I am not sure how we can
"know" the temperature history of other planets, and since Mars doesn't
have a magnetic field, it is not very useful in this case. Venus has a
runaway greenhouse effect going, and also neglible magnetic field. Just
because we don't believe magnetism has anything to do with current
global warming, doesn't mean it can't be a significant factor at all in
the future, or worth studying.
Michael Tobis wrote:
The more time series you look at the better the likelihood of a
correlation. If you look at twenty of them you are likely to hit a 95%
statistical significance. That's a long way from a theory.
Nobody has any suggestion, in this case, how magnetism affects climate
in pretty much exactly the way that CO2 is expected to (warmer
surface, colder stratosphere), nor any suggestion as to why CO2 should
be so kind as to fail to do so.
In any case one can easily examine temperature series on other planets
for a comparable temporal signature. If there were anything to this
we'd see the same thing on some of the solid planets or larger moons,
wouldn't we?
mt
On 12/19/06, mcbstrd <[EMAIL PROTECTED]> wrote:
>
> So this theroy that increased magnetic activity is responsible is
> unfounded?
>
> http://news.bbc.co.uk/2/hi/science/nature/358953.stm
>
> It seems to me at least to be internally plausible.
>
>
> >
>
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