Context
A recent study published in Geophysical Research Letters of the American Geophysical Union (AGU) says that our planet’s axis of rotation has been moving more than usual since the 1990s due to the significant melting of glaciers because of global temperature rise. This is said to be a new impact in the list of global climate change.
About the Earth’s axis of rotation
- Spin axis: The Earth’s axis of rotation is the line along which it spins while revolving around the Sun.
- The axis intersects the planet’s surface on the geographical north and south poles.
How the Earth’s axis shifts?
- Polar Motion: The location of the poles is not fixed and it moves when the axis moves. This movement of poles is known as polar motion.
- It is generally caused by changes in the hydrosphere, atmosphere, oceans, or solid Earth.
- Data support: According to NASA, data collected from the 20th century shows that the spin axis drifts about 10 centimetres per year.
- It has shifted due to polar motion by around 10 metres.
- The axis moves due to the Earth’s mass distribution around the planet.
- Now climate change is also adding to the degree with which the poles wander.
What are the key findings of the study?
- Reasons: According to the study some reasons have been attributed to the change in the poles position which includes:
- Melting glaciers: Since the 1990s, due to the climate change billions of tonnes of glacial ice has been melted into the oceans.
- This has caused the Earth’s poles to move in new directions.
- Groundwater depletion: The other possible causes are said to be due terrestrial water storage change in non?glacial regions.
- This is 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.
- Change in pole position: According to the study, the North Pole has shifted in a new eastward direction due to the changes in the hydrosphere.
- From 1995 to 2020, the average speed of drift was 17 times faster than from 1981 to 1995.
- In the last four decades, the poles have moved by about 4 metres in distance.
- Study: These calculations of shifts are 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.
Impact due to shift in Earth’s Axis
- The change in the axis position is expected to change the day length by a few milliseconds.
- It is said to not to make much changes in the daily life.
