As an example, we look at the LSL changes along the Dutch coast. There, a number of tide gauges have recorded LSL variations for more than five decades and some even more than a century. The monthly mean sea level values are available through the Permanent Service for Mean Sea Level (PSMSL). LSL trends for the Dutch tide gauges for the last ~50 years (lower right diagram) vary spatially between 0.9 mm/yr and 2.8 mm/yr. Since these tide gauges may not have captured the full range of spatial variations, we assume here a spatial variability of the local sea level trend at the Dutch coast of 0.7 mm/yr to 3.0 mm/yr for the last 50 years. Most of the spatial variability originates from spatially variable vertical land motion, while a smaller contribution comes from spatial variations in thermal expansion, ocean circulation and atmospheric forcing.'

There is also a temporal variation in trends on interdecadal time scales. Secular trends in LSL determined from Dutch tide gauge observations for the second half of the 20th century are generally larger than for the first half or for the full century *upper right diagram). Although the differences may not be statistically significant, we cannot exclude an increase of local sea level trends in the last fifty years or so. From Plag (2008).