Melting glaciers trigger movement of the earth’s crust


The Earth’s crust is shifting as climate change wreaks havoc on ice caps and glaciers around the world. The continued melting of these Greenland and Antarctic ice caps causes the earth’s crust to deform as water is redistributed into the world’s oceans, causing sea levels to rise.

The movement is due to a sudden loss of weight superimposed on the surface as massive chunks of ice melt, causing vertical and horizontal movement. While scientists have studied the vertical response to changes as the earth heaves, horizontal movement was followed for the first time.

In a study published in Geophysical Research Letters, a team of scientists found that surface motion averages several tenths of a millimeter per year and varies considerably from year to year. “The redistribution of mass between continents and oceans results in significant and time-varying crustal deformation,” the paper said as it set out to analyze the mass balance of ice caps and glaciers on a planet that is gradually warming up.

Studying the crustal movement

Under the direction of Sophie Coulson of Harvard University in Cambridge, the researchers gathered satellite data on ice loss from Greenland, Antarctica, mountain glaciers and ice caps and combined it with a model of the reaction of the earth’s crust to changes in mass.

They found that between 2003 and 2018, melting ice from the Greenland and Arctic glaciers forced the ground to move horizontally in the northern hemisphere, and up to 0.3 millimeters per year in a large part of Canada and the United States.

The loss of ice mass from Arctic glaciers also produces ubiquitous horizontal movements of magnitude up to 0.15 millimeters per year. They found that instead of being localized only to regions of ice loss, the melting of the Greenland ice sheet and arctic glaciers caused significant horizontal and vertical deformation of the crust that extends over a large area. part of the northern hemisphere.

Crustal motions are a key element observable in a multitude of geodynamic applications, including the estimation of ice mass changes as well as in a range of tectonic studies.

(Photo: Getty)

What is the earth’s crust?

The crust forms the outermost shell on Earth with a depth of up to 40 kilometers below the surface. According to the National Geographic Society, the crust is made up of solid rocks and minerals and the layers of the Earth constantly interact with each other, and the crust and the upper mantle are part of a single geological unit called the lithosphere. .

Just as the depth of the crust varies, so does its temperature. The upper crust withstands the ambient temperature of the atmosphere or ocean – hot in arid deserts and freezing in ocean trenches. The crust is made up of igneous, metamorphic and sedimentary rocks.

Climate change plays the bad guy

Climate change has triggered rapid loss of ice in the Arctic and Antarctic as well as the vast swathes of Greenland. Glaciers lose 31 percent more snow and ice per year than they did 15 years earlier. Scientists documented the massive loss of ice in April using 20 years of declassified satellite data.

They calculated that the world’s 220,000 mountain glaciers have lost more than 328 billion tonnes (298 billion metric tonnes) of ice and snow per year since 2015.

India will also be affected by the massive melting triggered by global warming, as 12 cities could be nearly a meter underwater by the turn of the century. NASA has identified 12 Indian cities that could be hit hard by climate change and sea level rise if the situation is not brought under control.

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