Fjords are slowly rising out of the sea as the Earth's crust bounces back from the weight of ancient glaciers.

This geological phenomenon is known as Post-Glacial Rebound or Glacial Isostatic Adjustment (GIA). During the Last Glacial Maximum about 20,000 years ago, ice sheets up to 3 kilometers thick covered much of Northern Europe and North America. The sheer mass of this ice was so great that it caused the Earth's lithosphere to flex and displaced the viscous asthenosphere beneath it.As the glaciers began to retreat rapidly around 11,000 years ago, the removal of this weight allowed the crust to begin its slow return to its original shape. According to data from the National Oceanic and Atmospheric Administration (NOAA), some parts of the Gulf of Bothnia in Sweden are rising at a rate of nearly 10 millimeters per year. This is one of the fastest uplift rates recorded on the planet today.The process is extremely slow because the mantle material beneath the crust is highly viscous and takes thousands of years to flow back into place. Scientists use GPS satellite data and sea-level gauges to monitor these changes with millimeter precision. In Fennoscandia, the land has already risen by about 800 meters since the ice melted, and researchers estimate it will continue to rise for at least another 10,000 years.This movement has significant practical impacts on modern geography and infrastructure. It causes sea levels to appear to drop locally, which can eventually turn shallow harbors into dry land and render old docks useless. Understanding GIA is also crucial for climate scientists who need to distinguish between local land movement and global sea-level rise caused by melting polar ice.