Figure 1 Sea Level Rise Observations Compared to Various Sea Level Rise Projections
Actual Sea Level Rise Trend :
The Portsmouth Harbor NOAA tide station ( currently at Seavey Island ) has extensive data gaps ( many years ) where no data were collected . The NOAA tide station in Portland , Maine , however does have continuous observed tide levels since 1912 . The Portland tide station sea level rise trend reported by NOAA has an average linear rise of 0.6 ft / 100 yrs , based on actual long term water level observations .