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Re: [Phys-L] Garth Paltridge: Climate Change's Inherent Uncertainties



If Jim is going to be tiresome, and appeal to the best data sources, then I am forced to respond in kind. So there!

*Thompson and Barnes* (p. 641 <http://app.aaas-science.org/e/er?s=1906&lid=40376&elq=a3faf0376e6a4cbb924d6d7100f34c83> Science) report the discovery of a 20- to 30-day periodicity in the atmospheric circulation in the Southern Hemisphere. The oscillation could potentially drive large-scale climate variability throughout much of the mid-latitude Southern Hemisphere.

Brian Whatcott Altus OK

On 2/6/2014 11:07 PM, Jim Diamond wrote:
rwt wrote:
"/snip/ This
is one model (amongst dozens) and clearly a worst case scenario. If there
were even a 10% chance of this outcome, the international scientific and
governmental responses would be shouting VERY loudly for immediate and
drastic action. The IPCC range of possible 2100 outcomes are much more
modest here."

/snip/

I'm going to ask some rhetorical questions, and answer them. I'm not going
to argue politics, but in retribution I will indulge in a final bit of
snark at the end.

OK, so what is the issue?

(A) Do you doubt we will hit the 900 ppm CO2 equivalent mark this century?
Don't debate me; look at the data.

1) Figure out the time scale yourself.
a) Go to the NOAA ERSL site and look at the yearly Average Greenhouse Gas
Inventory data from '79 to the present.
http://www.esrl.noaa.gov/gmd/aggi/aggi.html
b) look at the average increase in GHG concentrations since then and
compute the average annual increase (it is 1.56 % y/y)
c) Figure out how long will it take to get to 900 ppm CO2 equiv (this is
the RCP8.5 path) with that average annual increase in emissions. [2053 at
that rate].

Don't like that average increase? Fine. Pick another. let's choose the
average annual increase in the last decade. (it is 1.23 % y/y).
d) re-compute how long it will take to get to 900 ppm CO2; it will be
longer. Only 13 years longer.

2) Don't like this method? Fine. Come up with something else. I'll tell you
ahead of time - your results won't be drastically different. That is part
of the basis of the construction of RCPs.

B) OK, so you don't think that the snow and ice cover in the northern
hemisphere is disappearing?
1) No problemo. Go figure it out out for yourself.
a) Go to the Rutgers Snow and Ice Data center and look at monthly average
son cover for the Northern Hemisphere, Eurasia, North America w Greenland,
North America w/o Greenland. It is all here:
http://climate.rutgers.edu/snowcover/table_area.php?ui_set=2
b) It will take a bit of fussing on your part, but do a linear regression
on July Eurasia extent from 1972 (the first full year of data) to the
present.
c) Figure out how long it will take for the July Eurasia snow extent to
decrease to something statically indistinguishable from zero (the 95% CI
contains the years from the present to 2030). That means Northern
hemisphere snow and ice cover in Eurasia will be gone for the most part by
2030, 20 years before 2050.

C) Don't like the whole CMIP5 process?
1) /snip/ Go read about it yourself. Try a reliable source, like the AMS
journal.
http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-11-00094.1
"An Overview of CMIP5 and the Experiment Design...
The fifth phase of the Coupled Model Intercomparison Project (CMIP5) will
produce a state-of-the- art multimodel dataset designed to advance our
knowledge of climate variability and climate change. Researchers worldwide
are analyzing the model output and will produce results likely to underlie
the forthcoming Fifth Assessment Report by the Intergovernmental Panel on
Climate Change. Unprecedented in scale and attracting interest from all
major climate modeling groups, CMIP5 includes “long term” simulations of
twentieth-century climate and projections for the twenty-first century and
beyond."

I don't know about you, but I find this pretty hard to reconcile with "this
kind of garbage."

D) Still unhappy? So am I. Good luck with that.

And BTW, there is MORE than a 10% chance of RCP8.5 happening if we continue
to accelerate our emissions, and there are plenty of scientists (even the
American Chemical Society) who are deeply concerned about the consequences
of even the middle road RCP4.5. Just not too often on FOX.

Jim
--
James J. Diamond, Ph.D.
Professor of Chemistry
Linfield College,
McMinnville, OR 97128
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