Parts of northern Scandinavia are continuing to rise nearly 1 centimetre every year thousands of years after the enormous glaciers of the last Ice Age disappeared gradually transforming coastlines around the Gulf of Bothnia.
The phenomenon known as glacial isostatic adjustment, occurs because Earth crust is still recovering from the immense weight of the Scandinavian ice sheet that once covered the region. At its maximum around 20,000 years ago the ice sheet was up to about 3 kilometres thick in some areas and pushed the land downward.
Although the glaciers disappeared roughly 10,000 years ago the crust continues to rebound as the pressure beneath it readjusts. The uplift is strongest around the Gulf of Bothnia particularly near northern Sweden.
According to the NKG2016LU regional land uplift model the maximum absolute uplift reaches about 10.3 millimetres per year near Umeå in northern Sweden. Relative to the geoid, the rate is about 9.6 millimetres annually.
The movement is not uniform across Scandinavia. Land uplift is much faster in northern Sweden and Finland, while southern Sweden experiences considerably slower rates. In some parts of Skåne, for example, uplift is only around 1 millimetre per year.
Land rising faster than sea level
The ongoing uplift is significant because global sea levels are also rising. Between 2015 and 2024, global mean sea level increased by an average of about 4.7 millimetres per year.
In areas where the Scandinavian land is rising faster than the ocean relative sea level is therefore falling. This can cause shallow bays to narrow, islands to merge and former seabed to emerge as new land.
Sweden High Coast and Finland Kvarken Archipelago provide some of the clearest examples. The region is a UNESCO World Heritage site with land rising at roughly 0.9 metres per century.
Across Sweden and Finland the continuing uplift is estimated to expose around 700 hectares of land from the sea each year.
Coastlines gradually changing
As former seabed rises above the waterline, natural processes begin transforming it. New vegetation colonises exposed surfaces, while bays can gradually become wetlands, lakes and eventually terrestrial landscapes.
The High Coast has experienced particularly dramatic changes. Since the retreat of the ice around 9,600 years ago, relative uplift in the area has reached roughly 285 metres, leaving behind raised shorelines and former seabeds far above the present sea.
However, the balance between land uplift and sea level rise is not permanent. Glacial rebound is gradually slowing, while climate driven sea level rise is expected to continue.
As a result, some northern areas may continue experiencing falling relative sea levels for decades, while southern parts of Scandinavia are already seeing sea levels rise relative to the land.
The ongoing changes demonstrate how geological processes set in motion thousands of years ago continue to influence modern coastlines, ecosystems, navigation and coastal planning across northern Europe.