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On Jul 8, 2006, at 6:52 PM, FrankReedCT@aol.com wrote:

> Hi Fred, you wrote:
> "There was a lot of  "noise" in those data.  There's a strong linear
> trend, but there  also may be some non-linear ones as well.  There's a
> large spike  in the second half of the nineties, which MAY be related
> to the  current widely reported melting of the Arctic ice sheet, which
> only  started in the 90s, to my understanding.
> I'm not arguing about all the bs  surrounding global warming, just
> about these particular data and their  relation to the other data we
> have coming in.
> I agree about the  imprecision of the weather "forecasts" for the
> effect of rising  CO2."
>
> That web site includes some other very nice graphs. Here, for
> example, is
> the interannual  variation:
> http://tidesandcurrents.noaa.gov/sltrends/residual1980.shtml?
> stnid=8518750
>
> That  takes the same data set and subtracts the linear trend. If
> there's any
> quadratic  non-linearity, it would show up here. This also includes
> higher
> resolution for  the past 25 years and makes it much more obvious,
> in my opinion,
> that there's no  recent "spike". There's plenty of interesting
> noise and some
> of it can be  explained. For example, there's a bump in sea level
> in the early
> 1980s that's  connected with a well-understood long-period
> oscillation in the
> North Atlantic  (if memory serves, the Europeans had slightly lower
> than
> average sea level in  the early 1980s, but I don't know that for
> sure).
>
> By the way, the  break-up of the Arctic pack ice involves floating
> ice only
> and even if it melts  completely that does not change sea level. On
> the other
> hand, if the Greenland  glaciers go into high gear, then land ice
> becomes
> floating ice and this does  raise sea level. Although mountain
> glaciers are
> melting, and have been melting  for a long time, the quantity of
> water they
> contribute is relatively small. The  sea level rise that we see can
> still be attributed
> to global warming (of  whatever cause) but the mechanism is simple
> thermal
> expansion of the water in  the oceans. The same thing happens every
> summer at
> shore locations. Tides in  Connecticut (both high and low) are a
> bit higher in
> August than in January  because the water close to shore is much
> warmer. The
> Gulf Stream right now is  about four inches higher than the water
> to the north
> of it because it is much  warmer.


OK, I'm convinced.  Hadn't considered that the Arctic ice is already
in the ocean (and a lot of the Ross ice shelf in the Antarctic).  The
melting of land-bound ice may be delayed relative to other warming
that's occurring, lagging atmospheric temperature increase rather
than running with it or leading it.

Fred

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