Context:
A recent study says that humans have used enough groundwater to shift Earth’s tilt.
- The earth spins about its axis, which passes through its center, and this movement is called rotation.
- The ends of the axis are the North Pole and South Pole respectively.
- The axis is inclined 23.5 degrees away from the vertical, which means it is 66.5 degrees from the horizontal plane of its orbit.
- The earth rotates from west to east, and once every 24 hours.
- These are important fixed reference points we use in telling directions on the earth.
According to NASA, data from the 20th century shows that the spin axis drifted about 10 centimetres per year.
- Polar Motion – The phenomenon known as polar motion is the natural shifting of poles and the axis due to changes in the mass distribution of the planet.
- Reasons for polar motion – Ocean currents, hurricanes, climate-driven changes in water mass distribution, climate change, etc.
- Recent Findings – Between 1993 – 2010, a total of 2,150 gigatons of groundwater has been removed from earth.
- This has shifted Earth’s tilt 31.5 inches eastward.
- The calculations matched with previous research, which estimated that groundwater extraction raised global sea levels by 6.24mm between 1993 and 2010.
- Groundwater extraction from North America and northwestern India (located at the Earth’s mid-latitudes), had an enormous impact on the polar motion compared to the extraction in poles or equators.
Read also:- The rotation of the Earth
