Date: Sun, 4 Feb 2007 16:37:34 -0500 (EST)
To: letters@nytimes.com
Subject: Sea Level Rise

Regarding Andrew Revkin's article in today's Week In Review:

Most popular summaries of the subject of sea level rise in the Fourth
Assessment Report of the UN's IPCC misconstrue the predictions presented. In
the Third Assessment Report, released in 2001, the scientists attempted to
model the flow of ice off of Greenland and Antarctica in order to predict
the increased sea level in the year 2100.  Between 2001 and 2006, it became
clear that our understanding of melting glaciers was inadequate.
Accordingly, rather than speculate on the dynamics of melting, the report
simply includes the rate of ice flow as observed from 1993-2003, and allows
for no additional increase as the temperature warms up. Accordingly, the
upper limits on sea level rise was reduced to 20 inches or so, lower than
the numbers presented in the 2001 report.

Some (especially those disinclined to believe global warming to begin with)
are taking this to mean that the scientists have reduced their estimate for
the risk of larger sea level rises.  The rebuttal to this is found in the
text of the report itself, right below the column of numbers so often
quoted.  There it says, "Larger values cannot be excluded, but understanding
of [ice flow] effects is too limited to assess their likelihood or provide a
best estimate or an upper bound for sea level rise."

Your article seems to indicate that sea level rise is only something to be
worried about in the course of thousands of years.  Unfortunately, we still
don't know if that's true, and, unfortunately, there is no solace to be
found in the Fourth Assessment Report.

Mitch Golden