Dear David,
These guys are into calcite chemistry that is way beyond me. Even so
- you would think that the method is potentially more accurate than
fossil stomata. But Mr Hauser (?) is right in that we would need to
know the extent of ice in particular at the time but always
remembering that climate is dynamic (qualitatively behaves as a forced
nonlinear oscillator). I quote Hurrell et al from my climate as an
initial value problem - that the distinction between weather and
climate is 'somewhat artificial'. How about hopelessly untenable?
While we have such relatively large (in paleoclimatic comparison) ice
masses warming of 12 degrees C in 90 years is highly improbable -
complete ice melt over that period is highly improbable. Indeed, I
wonder if it is possible in the current age (quaternary) of rapid
repeated glaciation. The combination of continental uplift and
tectonic and orbital drift seems to have combined into a 'tipping
point' at ~ 120 ky intervals. What is it about the global heat engine
that triggers a glacial episode?
In the shorter term, all of the ocean/climate indices -
http://ioc-goos-oopc.org/state_of_the_ocean/all/ - are indicating
cooling this year and over the next decade or so. It takes quite a bit
of effort to integrate the indices and build a coherent global
picture. I call this real science as opposed to play station science
(and get called a denialist for my efforts) - we can't parametize the
unknown so it gets neglected. We can't for instance model ENSO very
well or the PDO, NAO, AO, SAM or IOD at all. Yet all these things are
empirical realities with huge implications for weather and climate. We
can't model future volcanoes, clouds, changes in solar activity beyond
the 11 year cycle or predict ice cover. And certainly not as a
dynamic nonlinear system.
Anthropogenic greenhouse gases increase climate instability and the
risk of abrupt climate change at decadal to ice age scales and
beyond. That's not something that is likely to be widely understood
for some time if at all. What the majority of the public is seeing is
that science has got it wrong and they are responding enthusiastically
to green overreach. So sad too bad.
Cheers
Robert
Cheers
Robert
On Jan 13, 11:24 pm, Tom Adams <[email protected]> wrote:
> Can't find a free version, but I have access at my work place.
>
> The paper says that the stomata index is considered less reliable at
> high atmospheric CO2 levels.
>
> The paper appears to argue that the findings in the paper tend to
> bring all the proxies into better agreement. (This is based on a
> really quick skim of the paper by non-expert me.)
>
> On Jan 13, 4:28 am, "[email protected]" <[email protected]>
> wrote:
>
> > > I would appreciate comments regarding how
> > > trustworthy this result is.
>
> > You wouldn't have a link to a free version of the paper?
>
> > I do notice that in the abstract they only mention one proxy line of
> > evidence. They do not mention stomata:
>
> >http://gsabulletin.gsapubs.org/content/121/9-10/1441.abstract
> > "Evidence for past CO2 spikes comes from expanded and refined stomatal
> > index data of fossil Ginkgo and related leaves. ...
>
> > The magnitude of the coming anthropogenic greenhouse pales in
> > comparison with past greenhouse spikes at times of global mass
> > extinctions."
>
> > My opinion is that the proxy evidence for CO2 concentrations is too
> > poor to distinguish 1000 and 7000 ppm reliably hundreds of millions of
> > years ago, and that we also need a better picture of other forcings in
> > the far past to conclude much.
>
>
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