Ice Age Aftermath: Nordic Land Mass Rising as Earth’s Gravity Shifts

In a finding that highlights the lasting impact of Earth’s glacial history, scientists have discovered that the Nordic region’s landmass is not only rising but is also more dense than previously known. This ongoing geological process, which began after the last Ice Age, is causing measurable changes in Earth’s gravitational field across the region.

Researchers at Sweden’s KTH Royal Institute of Technology have developed an enhanced method for tracking these subtle changes, revealing that the upper mantle beneath Fennoscandia—a peninsula encompassing Sweden, Norway, Finland, and part of Russia—has a density of approximately 3,546 kilograms per cubic meter. This figure, higher than earlier estimates, provides new insights into the region’s geological composition.

“Beginning 60 years ago, scientists were using terrestrial gravimeters to establish gravity reference system and study temporal changes in gravity associated with glacial isostatic adjustment,” explains Mohammad Bagherbandi, a researcher in geodesy and land surveying at KTH. “Our study is an alternative technique to study this phenomenon.”

The research, published in the Journal of Geodesy, combines multiple data sources including satellite observations, terrestrial gravity measurements, and 3D positioning from GPS systems. This comprehensive approach has enabled scientists to create more accurate models of how both the land and gravity are changing over time in the region.

The phenomenon, known as post–glacial rebound, occurs as land masses slowly recover from the weight of massive ice sheets that covered them during the last Ice Age. In Fennoscandia, this process results in land rising by approximately one centimeter per year—a rate that might seem minimal but has significant implications over time.

The study’s findings extend beyond pure scientific interest. Understanding these gravitational changes and land movements is crucial for multiple applications, from preparing for sea level changes to improving our ability to predict natural disasters. The research team utilized data from the Global Geodetic Observing System (GGOS), demonstrating the growing importance of satellite technology in Earth science research.

“This discovery helps us understand the slow ‘bounce-back’ of land after the Ice Age,” Bagherbandi notes. The research marks a significant step forward in our ability to measure and predict Earth’s dynamic processes.

Similar research is currently underway in North America, where scientists are studying an even larger region experiencing comparable uplift effects. These studies contribute to a growing body of knowledge about how our planet continues to respond to climate changes that occurred thousands of years ago.

The findings have particular relevance in the context of current climate change studies. As modern glaciers melt and ice sheets diminish, understanding how the Earth responds to such changes becomes increasingly valuable. The research provides a window into potential future geological changes as current ice masses continue to evolve.

The study’s enhanced measurement techniques, combining satellite data with traditional ground-based observations, represent an important advancement in geodesy—the science of measuring Earth’s geometric shape, orientation in space, and gravity field. This methodological improvement allows researchers to create alternative and comparable models of land and gravity changes, providing a more complete picture of Earth’s ongoing geological processes.