CR 18:141-146 (2001)  -  doi:10.3354/cr018141

Expected effect of climate change on Sylt island: results from a multidisciplinary German project

Kai Ahrendt*

GEOMAR Research Center for Marine Geosciences, Wischhofstraße 1-3, 24148 Kiel, Germany
Fig. 1. Overview of study area

ABSTRACT: Climate change (i.e. increasing mean sea level and storm activity) will influence the coastal development of sandy islands such as Sylt. To estimate the influence of climate change, a numerical model was used to predict the development of the coastline of Sylt island. Data for coastal retreat are available from 1876 to 1997 and were measured every 500 m longshore (~70 profiles). Wave data are available from 1986 to 1997. The model was calibrated and verified with these data. Coastal retreat was calculated to the year 2050 under the following scenarios (IPCC 1990): mean sea level +25 cm; tidal range +25 cm; wave height +10%; wave direction ±10°. Little change in the configuration of the coastline of Sylt is expected over the next 50 yr if the present strategy of western shore protection is maintained. No additional measures seem to be necessary. In contrast, if shore protection is not maintained, significant changes in coastline configuration (both west and east coasts) may occur, due in part to dramatic shore retreat by erosion, in the case of a 10% increase in wave height and a 10° change in all westerly wind directions toward the north. Only moderate changes in coastline configuration and weak shore retreat through erosion can be expected if wind direction is turned 10° to the south and wave height is maintained.

KEY WORDS: Climate change · Coastline development · Modelling

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