While many countries either don’t change in size or get smaller, Finland is only growing larger. Finland increases its surface area by about 2.7 square miles (4.3 square kilometers) every year because of a natural phenomenon.
It is known as the Fennoscandian land uplift, a gradual appearance of more land on Finnish coastlines. Observations were made as far back as 1491 when residents of the city of Östhammar noticed that the shoreline of their city had moved so much that they could no longer use their harbor. The same was happening in other areas of the country.
Early researchers thought it was being caused by sea levels dropping, but an entirely different phenomenon was at play. It wasn’t until a system of precise leveling was used, starting in 1892, that it was discovered that the sea levels weren’t dropping, but the land was rising.
It was found that retreating glaciers about 10,000 years ago were the cause, and the country was and continues to undergo what is called post-glacial rebound. The incredible weight of the glaciers long ago that were 1.2 miles thick (2 kilometers thick) compressed the land a little more than a quarter of a mile (about half a kilometer). When the glaciers receded, the underlying land was released from the enormous weight and began to rise.
It’s something it continues to do today, rising about 0.4 inches per year (10.1 mm), and in areas with the thickest ice, it rises about 0.79 inches per year (20 mm). Land is being added to the country very slowly, and it has about 328 feet (100 meters) still to go.
This phenomenon continues in other areas in the Northern hemisphere. Other Scandinavian countries, northwest Russia, and Canada have all experienced the effects of post-glacial rebound that will continue to add land to their coastlines.