Sea Level Research
Sea level research has always been a main and favorit topic. In 1969, Mörner was able to separate the eustatic and isostatic components behind the sea level changes recorded in the Kattegatt region from 40 dated individual shorelines followed for some 250 km in the tilt direction and related stratigraphic documentation. The further advancements from the basic Kaggegatt record in 1969 via its global tests to the formulation of the geoid-eustasy and later the rotational-eustasy concepts are described in the special pdf-file.


Pdf-1-1-1 kattegatt (144k)

The present – and future – sea level changes
This is a topic of much controversy. References are made to RT-5 of the INQUA Commission on “Sea Level Changes and Coastal Evolution”.

Mörner (1973) mirrored the uplifted Stockholm tide gauge record (from 1774) against the Amsterdam tide gauge record (from 1682) and arrived at only one solution giving a mean eustatic rise of 1.1 mm/yr from 1840 to 1930. A similar figure, ~1.0 mm/yr, was later obtained by Shennan & Woodworth (1992) for UK and the North Sea region.

The longest water-mark record in Sweden goes back to 1531 (Mörner, 1979, Fig. 0). The mean long-term thend is 4.6 mm/yr. The repeated levelling gives 3.5 mm/yr. So, even this comparision suggest a eustatic component of about 1.1 mm/yr.

If global sea level would have been rising in the last century, this should have led to a deceleration of Earth’s rate of rotation. Therefore, Mörner (1992) used the residual trend in the Earth’s length of day (LOD) record after filtering out the decadal changes, recalculated it to sea level changes and compared it to the Northwest European eustatic component. This indicates that global mean sea level may have risen by 1.1 mm/yr – not more, but well less (Mörner, 1992, 1995).

The combined satellite altimetry data indicate a mean rise in the order of 1.0 mm/yr from 1986 to 1996 (Fig. 7-5-4; Shum et al., 1999).

The last 150 years’ trend was ~1.0 mm/yr, the present trend is ~1.0 mm/yr and this value is likely to persist even in the next century. My personal evaluation (Mörner, 1995) is “10 cm, at the most 20 cm, in the next century.