Rising sea could erase a significant portion of coastal habitats in Finland

Researchers at Aalto University and the Finnish Environment Institute have for the first time investigated how a rising sea level might impact coastal habitats in Finland. The results are a cause for concern: in the scenario considered most likely to occur, 22–23 percent of coastal meadows and sandy beaches would disappear beneath the waves by the year 2100. Failure to reach emissions reduction targets could cause the sea level to rise more rapidly, causing even greater habitat loss.

‘Coastal habitats are crucial for biodiversity. Their destruction would be an irreplaceable loss to the nearly 700 species that inhabit sandy beaches and coastal meadows,’ says Senior Researcher Terhi Ryttäri from the Finnish Environment Institute.

The new study focuses on the Gulf of Finland coastline, as it is where land uplift is the weakest and thus where sea levels will rise sooner. In the north, land uplift along the coast of the Gulf of Bothnia will slow the impact of sea level rise, yet the area remains susceptible to its effects.

Coastal meadows and sandy beaches do not shift easily

The researchers also investigated whether coastal habitats could shift to areas further inland as the sea rises. They found that this kind of movement is hindered by, among others, the built environment, steep hills, and unsuitable soil.

‘Buildings, roads, and other infrastructure often block habitats from expanding to new areas. Even if there is space for them in theory, not all areas can transform into sandy beaches or coastal meadows,’ says Elisa Kropsu, a geospatial specialist who has completed a master’s thesis on the subject at Aalto University.

The research revealed that, in terms of land area, the space for potential expansion outstrips the coastal meadows that will be lost to sea level rise – in theory. In practice, most of this land is being used for agriculture, and transformation into coastal meadows is not always possible. The expansion of sandy beaches is more limited due to a lack of suitable soil.

Habitats require protection, restoration, and long-term planning

The researchers stress that immediate action is required to protect the coastal environment.

‘Possible measures include the expansion of protected areas, improving the natural state of existing areas, and reserving and preparing suitable expansion areas for coastal habitats,’ says Maaria Nordman, assistant professor of geoinformatics at Aalto University.

The study was published recently in the Boreal Environment Research journal.