According to a recent study conducted by the American Geophysical Union, 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 causing an increasing shift of earth’s axis.
Rising sea levels, heat waves, 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.
- Melting glaciers redistributed enough water to cause the direction of polar wander to turn and accelerate eastward during the mid-1990s, according to a new study.
- Between 2000 and 2019, glaciers lost 267 giga tonnes (GT) of ice per year, which now account for about a fifth of global sea-level rise.
- During the mid-1990s, melting glaciers redistributed so much water that it changed the direction of the routine “polar wander” to not only turn eastward but also accelerate, the researchers said.
- The study noted that the average drift speed between 1995 and 2020 increased about 17 times from the average speed between 1981 and 1995
What is 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 does the earth axis 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”.
|What is Polar Wander? Polar wander is the motion of a pole in relation to some reference frame. It can be used, for example, to measure the degree to which Earth’s magnetic poles have been observed to move relative to the Earth’s rotation axis.|
- It is to be noted that in the last 20 million years, the patterns of the pole has changed (or reversed) in every 200,000 years to 300,000 years.
- The pole shifting has resulted in the migration of North Pole towards Russia. This is also referred to as “Polar Wander”.
- 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. But now, climate change is adding to the degree with which the poles wander.
What does the new study say?
- 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.
- 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, according to Science Alert.
- The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s.
- The other possible causes are (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.
Movement of the Magnetic poles
- The magnetic pole was in the Canadian Arctic in the end of twentieth century. It then moved ten degrees moving towards the true North Pole. In 2001, the movement began to accelerate. In 2019, it had crossed the International Date Line. This is the fastest movement of the poles in human history.
- The shift in poles was done based on the data from GRACE mission.
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