According to a study which appeared in the Science Advances journal, ice in Greenland is melting comparatively faster than expected. The study reveals that from 2003 to 2013 Greenland lost 2,700 gigatons (2,700 billion metric tons) of ice. Previously, it was reported that 2500 gigatons were lost.
Commenting on the development, researchers from Ohio State University in the US disclosed that the hotspot that feeds Iceland’s active volcanoes has softened the mantle rock beneath Greenland. This will be ultimately distorting their calculations for ice loss in the Greenland ice sheet. This has caused researchers to underestimate the melting by about 200 billion metric tons or 20 gigatonnes per year.
Greenland lost 2700 gigatonnes of ice during 2003 to 2013
Meanwhile, Greenland did not lose around 2500 gigatonnes of ice from 2003-2013 as previously claimed. However, Michael Bevis, a professor at the Ohio State University said that it accounted to 2700 gigatonnes, which is roughly 7.6 percent more.
Bevis said that the crust of the Earth in that part of the world is slowly moving northwest. There are reports that over 40 million years ago, parts of Greenland passed through a very hot season of partially molten rock that now lies beneath Iceland.
Overall ice sheet of Greenland larger than current ones
During the previous ice age, the overall ice sheet was much larger than the current sheets. Moreover, the enormous weight has caused Greenland’s crust to slowly sink into the very soft mantle rock below it.
The existence of mantle flow beneath Greenland is not a surprise in itself
As soon as large parts of the ice sheet melted at the end of the ice age, the total weight of the ice sheet decreased. The crust also began to partially rebound. According to researchers, it is still rising since mantle rock continues to flow inwards and upwards beneath the region.
In 2002, the Gravity Recovery and Climate Experiment (GRACE) satellites began measuring gravity signals around the world. Around that time, scientists understood that they would have to separate mass flow beneath the Earth’s crust. This is to avoid changes in the mass of the overlying ice sheet.
GRACE measures mass, period. It cannot tell the difference between ice mass and rock mass.
If you are unaware, models of this rock flow depend on the viscosity of the mantle that researchers can fetch. The models released initially rely on a fairly typical mantle viscosity. However, the land’s proximity to the Iceland hot spot greatly changed the picture.