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Climate change and its impact on Earth’s axis

Climate change and its impact on Earth’s axis

CONTEXT:

  • A new study says that due to the significant melting of glaciers because of global temperature rise, our planet’s axis of rotation has been moving more than usual since the 1990s.

The Sun and the Earth:Earth's Rotation and Revolution | About Sundials |  SEIKO Kids

Climate change and axis of rotation:

  • Rising sea levels, heatwaves, melting glaciers and storms are some of the well-known consequences of climate change.

  • New research has added yet another impact to this list – marked shifts in the axis along which the Earth rotates.

  • Impact: While this change is not expected to affect daily life, it can change the length of the day by a few milliseconds.

  • Study was published in Geophysical Research Letters of the American Geophysical Union (AGU).

Earth’s axis shifts and Polar Motion:

  • Along spins: The Earth’s axis of rotation is the line along which it spins around itself as it revolves around the Sun.

  • Poles: The points on which the axis intersects the planet’s surface are the geographical north and south poles.

  • Location of poles: The location of the poles is not fixed, however, as the axis moves due to changes in how the Earth’s mass is distributed around the planet.

  • Polar motion: Thus, the poles move when the axis moves, and the movement is called “polar motion”.

  • Spin axis drift: According to NASA, the spin axis drifted about 10 centimetres per year. Meaning over a century, polar motion exceeds 10 metres.

  • Cause of Polar Motion: polar motion Generally, polar motion is caused by changes in the

    • Hydrosphere,

    • Atmosphere,

    • Oceans, or

    • Solid earth. But now,

    • Climate change is adding to the degree with which the poles wander.

New study on Earth’s axis shifts due to climate change:

  • Glacial melt: Since the 1990s, climate change has caused billions of tonnes of glacial ice to melt into oceans. This has caused the Earth’s poles to move in new directions.

  • As per the study, the north pole has shifted in a new eastward direction since the 1990s, because of changes in the hydrosphere (meaning the way in which water is stored on Earth).

    • Also, in the last four decades, the poles moved by about 4 metres in distance.

  • GRACE mission: The calculations were based on satellite data from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission as well as estimates of glacier loss and groundwater pumping going back to the 1980s.

  • The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s.

  • Other possible causes:

    • Terrestrial water storage change in non-glacial regions due to climate change and

    • Unsustainable consumption of groundwater for irrigation and other anthropogenic activities.”

    • While ice melting is the major factor behind increased polar motion.

    • Groundwater depletion also adds to the phenomenon. As millions of tonnes of water from below the land is pumped out every year for drinking, industries or agriculture, most of it eventually joins the sea, thus redistributing the planet’s mass.

SOURCE: Indian express