Dear Ken,
Thanks for pointing out the poor phrasing in our article, but I would
prefer that we discuss it first among ourselves and not through the
[geo] listserv.
In your paper you say:
"Depending on the amount of insolation reduction and where it is
reduced, simulated sea ice extent at the annual minimum can be adjusted
at will."
"In the model, Arctic temperatures can be adjusted at will by adjusting
the amount of insolation reduction and the area over which the reduction
occurs."
"One could infer that a non-uniform reduction in solar intensity,
wherein more sunlight would be deflected in the high latitudes, would
eliminate most of the area with statistically significant residual
annual mean temperature change in high-latitude regions."
"From a practical point of view, the Arctic is changing very rapidly so
it is an obvious early target for geoengineering."
"The goal of these simulations was to estimate the amount of insolation
reduction needed to bring the Arctic climate in a high CO2 world climate
closer to that of the pre-industrial state."
Except for a table with a few global numbers for the Arctic experiments
and Fig. 3, with shading of annual average temperature changes for all
the experiments, you say nothing about the global effects of the Arctic
experiments or any effects on precip outside the Arctic in the text. It
is hard to tell from the shading in Fig. 3 what the effects outside the
Arctic are, and they appear small.
So while it is true that you do not explicitly say that effects of
Arctic geoengineering could be confined to the Arctic, clearly that is
the intent of the experiments you conducted, and you also do not say
that the effects would not be confined. You imply that effects outside
the Arctic would be small.
How would you feel about the following rephrasing?
"/Some authors (4) have proposed controlling Arctic temperatures and sea
ice at will by reducing insolation just over the Arctic, without
addressing lower latitude climate effects."
/
Alan
Alan Robock, Professor II
Director, Meteorology Undergraduate Program
Associate Director, Center for Environmental Prediction
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
On 2/28/2010 10:11 PM, Ken Caldeira wrote:
Gentlemen,
In your recent Science Perspective piece (29 January 2010, vol 327,
530 - 531), you wrote:
/"Some authors have argued that the effects of polar testing could be
confined to the Arctic (4)."/
CItation (4) is:
/
K. Caldeira, L. Wood, //Philos. Trans. R. Soc. London Ser. A *366*,
039 (2008)/
[available for free download at:
http://rsta.royalsocietypublishing.org/content/366/1882/4039.full]
Nowhere in this paper do we argue that the effects of polar testing
could be confined to the Arctic.
In fact, we showed that even for the idealized case in which sunlight
is reduced only over the Arctic, effects would be at least hemispheric
(See Fig 3, panels b, c, d, and e).
I think it is unfair to be criticized in Science for claiming that
effects of polar testing could be confined to the Arctic when our
paper shows that even in the unrealistic case where solar insolation
reduction is confined to the Arctic, effects would not be confined to
this region.
Our paper is cited to support a statement that our paper in fact
refutes. An appropriate citation would have been:
/"Some authors (4) have shown that, even if solar insolation could be
reduced only over the Arctic, effects of polar testing would not be
confined to this area."/
It is unpleasant to be set up as a straw man.
I think a correction is in order.
It is important that we respond to what people actually write and not
what we imagine people may have written.
Regards,
Ken
PS. Our paper describes a set of highly idealized sensitivity
experiments. I think we made this clear with statements such as:
/
We present results of several climate simulations designed to estimate
the climate consequences of idealized patterns and degrees of
insolation reduction.
From a theoretical point of view, it is interesting to explore
relationships between forcing and response in different latitude
bands, to get a better idea of the degree of nonlinearity of the
climate system.
We recognize that these simulations are highly idealized and that real
climate engineering is unlikely to produce step function changes in
radiative forcing at a defined latitude./
/We have presented highly idealized numerical simulations of extremely
simple climate engineering involving spatially uniform reductions of
incoming sunlight at the top of the atmosphere over specified northern
polar regions and the entire Earth. /
PPS. For the foreign language speakers on this group, an explanation
of "straw man" can be found at: http://en.wikipedia.org/wiki/Straw_man
/A *straw man* argument
<http://en.wikipedia.org/wiki/Logical_argument> is an informal fallacy
<http://en.wikipedia.org/wiki/Informal_fallacy> based on
misrepresentation of an opponent's position.^[1]
<http://en.wikipedia.org/wiki/Straw_man#cite_note-book-0> To "attack a
straw man" is to create the illusion of having refuted a proposition
by substituting a superficially similar proposition (the "straw man"),
and refuting it, without ever having actually refuted the original
position.^[1]
<http://en.wikipedia.org/wiki/Straw_man#cite_note-book-0> ^[2]
<http://en.wikipedia.org/wiki/Straw_man#cite_note-files-1> /
___________________________________________________
Ken Caldeira
Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
[email protected] <mailto:[email protected]>
http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1 650 704 7212; fax: +1 650 462 5968
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