Modelling Coastline Change of the Darss-Zingst Peninsula with Sedsim - The Baltic Sea Basin - page 290

Fig. 14.6 Sea level model for the study area for the next 840 years. Data source : Voß et al. ( 1997 )
rough spatial horizontal resolution with 5.6 ◦ . Therefore Voß et al. ( 1997 ) do not pro-
vide values for the Baltic Sea itself. The average of bordering model cells from the
North Sea and the Northern Atlantic is used as a sea level model for the study area
(see Fig. 14.6 ) . In this study we focused on the CO 2 quadrupling scenario with a
modelled rise of the sea level for the next century of 21 cm. More recent global sea
level rise scenarios (IPCC 2007 ) suggest a range in sea level rise for the next 100
years from 18 to 59 cm. In comparison, the data we used have to be considered as a
“best-case scenario”, with 21 cm at the lower border of the range. This value is also
within the range of the scenarios proposed by Meier et al. ( 2004 ) for the Baltic Sea.
They take sea level rise values of 9, 48 cm, or, in a worst-case scenario, 88 cm as
basis for modelling towards the end of the century.
The speed of our sea level rise scenario is about 1.7 mm/year and does not accel-
erate. This seems to be in contradiction to recent findings, e.g. Hammarklint ( 2009 )
who postulates an increase of the speed of the sea level rise during the last 30 years
from 1.5 up to 3 mm/year. In the frame of a 840-year-long time series a time span
of 30 years covers only a small interval and such an increase can be considered as a
fluctuation. Although in summary linearly, the sea level rise is always superimposed
by an oscillation with times of increase and decrease, reflecting irregularities in the
behaviour of a complex natural system.
The sea level time series is parameterized by the Sedsim module SEA LEVEL.
The projected sea level rise scenario for the next 840 years is shown in Fig. 14.6 .
The sea level rise continues even after the end of the increase in CO 2 concentration
after 120 years. This is caused by long-term global oceanic circulations responsible
for the heat transfer between atmosphere and ocean.