Observed and Projected Sea Levels At Lerwick

Data source www.psmsl.org Date extracted 16-Nov-11

The green dots are the actual observations, or more precisely each dot is the average of one month's observations. The lower black line is the linear trend line of these dots. The upper curving line shows DEFRA 2006 predictions.

The High Medium and Low DEFRA 2009 predictions are the curves in the middle.

For some reason even though these predictions were published in 2006 and 2009 both start from 1990. This allows us to compare how the predictions match observations from 1990 until now. If there is a major difference this means the predictions are wrong and any plan based upon them should be re-examined.

How likely do you think it is that sea levels will rise as predicited by DEFRA 2006 or even as predicted by the Low DEFRA 2009?

The trendline shows a sea level rise of -0.11 mm/year.

The observations in the graph above are what PSMSL call 'RLR data' or 'Revised Local Reference'. You can read more about RLR data here

RLR data ensures for all stations around the world.

  1. Sea level is about 7000mn.
  2. If tide gauge is moved the RLR dataset is adjusted to reflect any change in height. This means there is the possibility of apparent sea level rise or fall being introduced into the RLR dataset if the adjustment is not correct.

Here are the unadjusted observations for Lerwick