A recent study has found that as the polar ice sheets melt, the underlying surface of the Earth is warping, causing the crust to rise and spread. This movement covers a vast area, although the amount is minimal, with an average of less than a millimetre a year. The research found a feedback loop, where the bedrock shifting under the ice affects how the ice continues to melt and break away, making a full understanding of this process essential in modelling our future world.
Scientists had previously documented the uplift that occurs as ice sheets melt, but the recent study by geophysicists from Los Alamos National Laboratory went further, focusing on horizontal shifts over a wider area. They found that crust deformations can vary significantly from year to year, with some horizontal movement exceeding the vertical. Using satellite data and field measurements from 2003 to 2018, the researchers measured crust movement in three dimensions.
These crust rebounds in thousands of years, with some changes still being felt across the Earth's surface from the end of the last ice age, some 11,000 years ago. They explained that on recent timescales, we think of Earth as an elastic structure, like a rubber band, but on timescales of thousands of years, it acts more like a very slow-moving fluid. Earth's processes during an ice age take an extended period to play out; therefore, the results of these processes can still be seen today.
Researchers explained that understanding all the factors that cause the movement of the crust is crucial for a wide range of Earth science problems.