The Danish coastline has continually changed since the last ice age with relative subsidence in the south and uplift in the north. The result is a low-lying country with raised beaches and wide marine forelands in the north and an archipelago in the south. The coastline is relatively long (7400 km) for an area of 42,000 km2. Eighty percent of the population of 5.33 million (1 January 2000) live in municipalities with a coastline. Vulnerable low-lying areas contain 60,000 to 70,000 properties. These areas are mainly raised sea floor, marshes, and reclaimed areas. On the basis of present vertical movements and projected global accelerated sea-level rise (ASLR) it is estimated that relative sea level will increase by 33–46 cm within the next 100 years—notably in the southwestern part of Denmark. Increased storm intensity may enhance the impacts of this change in water level.
Dikes protect about 1100 km of the coastline and hard structures about 700 km. Soft solutions, especially beach nourishment, are increasingly used. So far direct planning for sea-level rise above the current secular rise has been modest and purely qualitative. The same applies to most new and upgraded coastal infrastructure, where the approach has largely been a “wait and see” attitude. Economical evaluations have been either unofficial or absent.
More attention has been paid to the impacts on coastal ecosystems, especially saltmarshes and sand dunes. Here the choice of action will depend on attitudes to and weighing of economic, sociological, and biological interests and options. The general strategy appears to be toward the preservation of a natural coastline, if necessary at the cost of land loss.