Assessment of 20th century sea level rise in New Zealand including measurement inaccuracyAuthor(s): Albert Parker
The relative rate of rise of sea level is traditionally computed by linear fitting of the data collected over a time span long enough without gaps and measurement issues. This procedure returns on average small rates of rise and zero time rates of change of these velocities. This is the best available measure of the effects of global warming on sea levels. The use of GPS to infer the vertical velocity of the tide gauge introduce significant inaccuracies, and even larger inaccuracies are provided by computations linked to satellite altimetry or proxy data. There is no reason to search for alternative methods simply because the climate models predicted different trends.