File:Recent Sea Level Rise.png From Global Warming Art This
figure shows the change in annually averaged sea level at 23
geologically stable tide gauge sites with long-term records as
selected by Douglas (1997). The thick dark line is a three-year
moving average of the instrumental records. This data indicates
a sea level rise of ~18.5 cm from 1900-2000. Because of the
limited geographic coverage of these records, it is not obvious
whether the apparent decadal fluctuations represent true
variations in global sea level or merely variations across
regions that are not resolved. For comparison, the recent
annually averaged satellite altimetry data  from TOPEX/Poseidon
are shown in red. These data indicate a somewhat higher rate of
increase than tide gauge data, however the source of this
discrepancy is not obvious. It may represent systematic error in
the satellite record and/or incomplete geographic sampling in
the tide gauge record. The month to month scatter on the
satellite measurements is roughly the thickn