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Climate change causing a shift in Earth’s axis

Topics Covered: Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.

Climate change causing a shift in Earth’s axis:


Context:

According to a study, 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.

Implications:

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

What is the Earth’s axis?

The Earth’s axis of rotation is the line along which it spins around itself as it revolves around the Sun. The points on which the axis intersects the planet’s surface are the geographical north and south poles.

How it shifts?

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

  • According to NASA, data from the 20th century shows that the spin axis drifted about 10 centimetres per year. Meaning over a century, polar motion exceeds 10 metres.
  • Generally, polar motion is caused by changes in the hydrosphere, atmosphere, oceans, or solid Earth.

What the new study says?

  • 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).
  • From 1995 to 2020, the average speed of drift was 17 times faster than from 1981 to 1995. Also, in the last four decades, the poles moved by about 4 metres in distance.

Latest factors behind this change:

  • The faster ice melting, change in non‐glacial regions due to climate change and unsustainable consumption of groundwater for irrigation and other anthropogenic activities.
  • 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.

InstaLinks:

Prelims Link:

  1. Earth’s poles.
  2. Differences between geographic and magnetic poles.
  3. Causes for shifts.
  4. Implications.

Mains Link:

How climate change results in shift in Earth’s axis? Discuss.

Sources: Indian Express.