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10 November 2020.
Introduction:
NASA recently announced that the Earth Mass has deviated in August 2020 as compared to that of 2004-09.The increase in sea level may be due to the change in earth mass.
Highlights:
- The change in earth mass is mainly caused due to land movement relative to sea.
- The changes in land movement was more in snow- and ice-covered regions.
- This is because, here the ice cover is disappearing and the surface mass of the earth is being lost.
- NASA released maps showing how several factors affect the sea level increase.
- The natural drivers such as shifting of tectonic plates, compression of buried ocean sediments produce gradual motion.
- In addition to these, the human driven factors such as ground water extraction, oil production and drying of peat soils also cause land motion.
- The Global Navigation Satellite System (GNSS) helped analyse land movement.
- According to NASA, oil production and ground water extraction can produce subsidence at the rate of centimetres per year as compared to milli metres per year as caused by natural processes.
Reasons for change in earth masses
- The changes were mainly because changes in amount of water, ice and snow. These changes were calculated by GRACE Mission.
- It was a joint mission by NASA and Germany. GRACE mission found that there were mass losses of Greenland ice sheet between 2002 and 2016.
- The mission also found that between 2002 and 2017, there were mass losses of 1.2 milli metres per year.
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