Hi All
Alan says that climate signals will be drowned out by chaotic climate
variations. Both the papers that I pointed to in my email of 24
September were about picking up small signals from large, random
variations. The second paper suggests that a 20 year run of the
pseudo-random stimulus idea might be able to detect changes which are
one or two percent of the root mean square of the natural variation. I
am still hoping for suggestions.
If I knew a bit more about chaos I would like to argue whether or not
the climate is chaotic or we are just ignorant about climate. The best
scientists and philosophers used to think that planetary motions, the
behaviour of chemical elements and the incidence of infectious illnesses
were chaotic. Believing that something is chaotic is an excellent way
of never discovering useful things about it.
Stephen
Emeritus Professor of Engineering Design
Institute for Energy Systems
School of Engineering
Mayfield Road
University of Edinburgh EH9 3JL
Scotland
Tel +44 131 650 5704
Mobile 07795 203 195
www.see.ed.ac.uk/~shs
On 28/09/2010 20:44, Douglas MacMynowski wrote:
Alan - I doubt there's any real disagreement here, but just a
clarification; climate variability/noise is irrelevant to the question
of whether some form of SRM can be tested, but of course critical to
the question of how long it would take to detect a signal. If the
goal is to estimate changes on a global scale, that will take decades
and significant forcing levels (we have a paper under review on this
subject that puts numbers on that trade-off). Other than the moral
hazard, I see no basic difference between testing this, and any other
experiment in any other field of engineering or science. Clearly with
one Earth, I agree with learning everything we can with computer
testing first, but if we ever did want to do this in full-scale, I'd
rather start small and learn something rather than just turning it on
and hoping for the best.
doug
On Sep 27, 11:44 am, Alan Robock<[email protected]> wrote:
Dear Ken,
I think you are being rather picky with words. In any case, I never
said it cannot be tested. I said it cannot be fully tested in a
real-world in situ experiment without full-scale implementation, because
the climate signal will be drowned out by chaotic climate variations and
because injecting into a pristine stratosphere cannot test injecting
into an existing cloud. Of course computers can be used for testing.
That is what I do, and I advocate much more of it. The statement below
refers to in situ experimentation.
Alan
Alan Robock, Professor II (Distinguished Professor)
Editor, Reviews of Geophysics
Director, Meteorology Undergraduate Program
Department of Environmental Sciences Phone: +1-732-932-9800 x6222
Rutgers University Fax: +1-732-932-8644
14 College Farm Road E-mail: [email protected]
New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock
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