From UPSC perspective, the following things are important :
Prelims level : Polar shift
Mains level : Paper 3- How climate change causing a shift in the Earth's axis of rotation
About the study
- A study is published in Geophysical Research Letters of the American Geophysical Union (AGU).
- The study has added yet another impact of climate change on the earth – marked shifts in the axis along which the Earth rotates.
- It 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.
How the earth’s axis shifts
- 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.
- 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”.
- 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.
What the study says
- 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.
- The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s, the study says.
- The other possible causes are terrestrial water storage change in non‐glacial regions due to climate change and unsustainable consumption of groundwater.