Saturday, April 14, 2012


date: Fri, 17 Sep 1999 11:26:31 -0700 (PDT)
from: Philip Mote <>
to: jim obrien <>

Jim et al.,

Greetings from the other corner of the Lower 48.

In response to your latest message, there are stronger ways to make your
case than by claiming that the difference between 10 and 7 is
statistically significant. There is a whole body of literature, of which
I'm sure you're aware but other recipients of your messages may not be, on
trends in tropical cyclones (TCs) (a more general term than "hurricanes")
and on the impacts of climate change on TCs. See, for example, pages
169-170 of the 1995 IPCC report (vol I). The trends in intense Atlantic
hurricanes are indeed downward, as your landfalling dataset points out.
We know about the link that goes El Nino--> fewer hurricanes, but echoing
Peter's previous message, do we know yet that climate change-->more El
Ninos? the modeling results so far seem (to me) inconclusive.

As for future trends in TC's, there seems to be a tendency for models to
suggest decreasing trends in TC's, though this too is inconclusive
(IPCC95, p. 334). More recent modeling work (e.g., Royer et al., Climatic
Change 38, 307-343, 1998) suggests an increase in TC frequency but no
extension of the area in which TC formation occurs. I'm sure there are
lots of other recent relevant papers but I haven't read them as this is
only a peripheral interest of mine, not my field of expertise.

All of this is to lead to the suggestion that, as a general principle,
whether we're talking to the media or to each other, we make such
statements based on the IPCC consensus wherever possible. AND WITHOUT
SHOUTING. (by internet protocol, ALL CAPS means you're shouting---but
maybe that's what you intended. Besides, lowercase letters are easier for
the brain to process.)


Philip Mote, PhD
JISAO/SMA Climate Impacts Group
Box 354235, Univ. of Wash. Seattle WA 98195
phone (206) 616-5346 fax (206) 616-5775

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