A new study suggests melting ice from glaciers and landmasses is causing the Earth’s crust to warp.
Led by Sophie Coulson of Harvard University in Massachusetts, scientists studied the effects of melting ice by looking at early 21st century ice loss from Greenland, Antarctica, mountain glaciers and ice caps using data derived from satellites, and combined it with a model of how the Earth’s crust responds to changes in mass.
Though there have been previous studies about the vertical response of the land in relation to ice loss, this study instead focuses on the horizontal movement of the ground.
In the study, published in the journal Geophysical Research Letters, the researchers describe how ice melting from Greenland and the Arctic glaciers has ’caused the ground to shift horizontally’ across much of the Northern Hemisphere between 2003 and 2018.
The ground has changed by as much as 0.3 millimetres a year in large parts of Canada and the US, with the Earth’s crust thought to lift in response to the sudden loss of overlaying weight on the surface as massive chunks of ice melt. The crust forms the outermost shell of Earth and extends to around 40 kilometres under the surface.
The melting, which sees water redistributed to global oceans, could cause a pattern of 3D motions at the Earth’s surface as far as 1,000 kilometres away from the ice loss. On average, the surface motion is ‘several tenths of a millimetre per year, and it varies significantly year to year’, according to the scientists.
They explain: ‘We show that, rather than only being localised to regions of ice loss, melting of the Greenland Ice Sheet and Arctic glaciers has caused significant horizontal and vertical deformation of the crust that extends over much of the Northern Hemisphere.’
Having considered the past data, the scientists predicted the Earth’s crust would be deformed by 0.05–0.3mm per year in most parts of Canada and the US, and 0.05–0.2mm per year in Europe, including parts of the region which constitutes Finland, Norway and Sweden.
The study states: ‘The redistribution of mass between continents and oceans results in significant and time-varying crustal deformation.’
Researchers believe more studies are needed to further assess the warping of the Earth’s crust due to melting ice, to improve both horizontal and vertical measurements made by navigational satellite systems.
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Geophysical Research Letters
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