Coastal erosion Sweden
The Swedish coast has a total length of approximately 11,500. Sand beaches mainly occur in the southern part of the country (Scania), and along the coasts of large islands in the Baltic Sea (Öland and Gotland) and archipelagos along several parts of the coast. Coastal erosion occurs primarily along the Scanian coast and adjacent coastal areas, on pocket beaches and soft cliffs of archipelagos near Gothenburg, Stockholm, Piteå and Luleå, and on cliffs on Gotland (1).
Relative sea level rise near the Scanian beaches varies between 0-1 mm/year. Water level variations at Scanian beaches due to wind and differences in air pressure are pronounced because of the limited Baltic Sea water mass. High and low water levels can be up to 1.7 m above and 1.5 m below Mean Sea Level, respectively. The tidal variation is negligible. Beach erosion along the Scanian coast may be classified into 3 categories (1):
- Beaches where man-made structures disturb equilibrium conditions, typically in a pocket beach;
- Stretches of open coast that are locally out of equilibrium with the prevailing wave climate, and where the influence of man is secondary;
- Dunes and cliffs that are attacked during storms when high waves and water levels prevail.
Cases of most severe beach erosion have erosion rates of 1-2 m/year (1).
The global rise in sea level of 88 cm gives a rise in average water level of about 80 cm in southern Sweden (up to Östergötland) at the end of the century, 50 cm in the central region (up to Uppland) and 20 cm in the northern region, taking into account subsidence. In northern Sweden, land elevation and any rise in sea levels essentially counter each other (3). The possible impact of sea level rise due to climate change on dune erosion was calculated for the Scanian coast near Ystad. Results indicate a 25% dune erosion increase until 2100 for the average sea level rise scenario (+38 cm) and a 75% increase for the most extreme scenario tested (+85 cm) (1).
Land uplift is taking place in most of Sweden as a result of the melting of the massive land ice of the last ice age, but in the southernmost part of the country uplift has come to a halt. The ongoing rise in sea level is therefore leading to substantial coastal erosion along Sweden’s southern coast where the land consists of easily eroded soils. Climate change as a consequence of future increased atmospheric temperature will strengthen this erosion (3). The stretches of coast at greatest risk are in Skåne and Blekinge and on the islands of Öland and Gotland (4).
Waterside housing has become increasingly sought-after. An increasingly large proportion of construction is taking place in the coastal zone (5 km from the coast), in southern Sweden almost half. Just over 30 per cent of buildings in the country are located in the coastal zone. The proportion of buildings constructed within 100 m of the shoreline more than doubled between the 1970s and the end of the 1990s, according to a report from the National Board of Housing, Building and Planning. This shoreline building development occupies around 30 per cent of the total coastline of Sweden (4). With respect to the impacts of climate change, 10-15% of the development along the coast may have to be protected in the future (2).
Coastal erosion must be viewed in a wider perspective based on the interests of society. The point of departure ought to be that nature has its way in areas where there are no private or public interests or values at threat. Through planning processes the local authority is responsible for localising development to land suited to the purpose. If values of importance are threatened, such as development, infrastructure and other areas worthy of protection, measures may be appropriate. Areas of great natural or recreational value can also be important to protect, but are of secondary importance (4).
According to the Swedish Commission on Climate and Vulnerability (4), the compensation system for preventative measures in the event of natural disasters should also include beach erosion. Erosion has thus far been interpreted as a natural disaster with a slow course of events, even though it can eventually lead to rapid events with major losses of land or development. Climate change with rising sea levels, higher winds and possibly changed currents can lead to the risk of threatened values increasing.
According to calculationsof the Swedish Commission on Climate and Vulnerability (4), around 150,000 buildings are located in an area susceptible to erosion in the case of a rise in sea level of 88 cm.The value of these properties amounts to approximately SEK 220 billion.
A rough estimate of the cost of protecting against beach erosion (protection and beach nourishment) along these 220 km is SEK 2.7–5.4 billion. In addition to this, the annual maintenance cost amounts to SEK 3,000–4,000 per metre of coast (5). So far, coastal protection measures have almost exclusively been hard structures, but soft solutions such as beach nourishments are now being carried out at several locations (1).
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Sweden.
- Larson et al. (2013)
- Rydell (2007)
- Ministry of the Environment of Sweden (2009)
- Swedish Commission on Climate and Vulnerability (2007)
- Rydell (2007), in: Swedish Commission on Climate and Vulnerability (2007)