For a long time, human actions have had little effect on the motion of the Earth, i.e. its rotational speed or axis.
These movements were primarily governed by the Moon’s gravity and internal processes in its core and mantle.
However, human activities are currently melting the ice sheets, disrupting these natural processes.
A new study has revealed that the Earth’s axis is “shifting” due to climate change and dynamics within the planet.
Researchers at ETH Zurich have used cutting-edge AI models to better understand polar motion, the movement of the Earth’s axis of rotation relative to the crust.
The study predicts that if greenhouse gas emissions continue to rise, they will eventually outweigh the long-standing influence of the moon’s tidal forces, which have dictated the steady lengthening of our daylight hours for billions of years.
“We humans have a much greater impact on the Earth than we realise, and so naturally we bear a great deal of responsibility for its future,” said Benedikt Soja, professor of space geodesy at ETH Zurich’s department of civil, environmental and geodesy engineering.
The days get longer
Two recent studies have explored a surprising connection between melting ice sheets, the shaking of the Earth, and the length of our day.
As the ice at the poles melts, mass is redistributed toward the equator, slowing the Earth’s rotation. Water moves from the poles to the equator, throwing the Earth out of equilibrium.
As the ice on the Earth’s surface melts, the planet’s rotation slows down, lengthening the length of its day. According to research from ETH Zurich, this slowdown adds a small amount of extra time to a day – just a few milliseconds compared to the usual 86,400 seconds.
In physics, there is a law called the conservation of angular momentum. This basically says that any object that spins will continue to spin at the same speed unless something forces it to change. The Earth’s rotation also follows this law. When ice melts, mass is redistributed, and this change causes the Earth to rotate slower, according to the law.
“This means that a change in mass is occurring, which is affecting the Earth’s rotation,” Soja explained.
Impact on the Earth’s core
The researchers also studied why and how the Earth’s axis shifts gradually over long periods of time. Using a physics-based neural network, the team created the most comprehensive model to date, explaining how movements in the Earth’s core, mantle and surface climate affect polar motion.
The two studies highlight the complex web of interactions within the Earth’s interior. Events on the surface, such as Melting icecan have an impact deep within your core, and vice versa.
“Climate change is shifting the Earth’s axis, and feedback from the conservation of angular momentum appears to be changing the dynamics of the Earth’s core as well,” Soja explained.
As the polar ice melts, the water moves from the poles towards the equator, slowing down the Earth’s rotation. BulkyBenedikt Soya explained that this phenomenon is similar to how a figure skater rotates slower when his arms are extended than when they are bent – the same principle also applies to the rotation of the Earth.
“Ongoing climate change may be affecting deep processes within the Earth’s interior more than previously assumed,” added Kiani Chavandi, a doctoral student and lead author of the study. press release.
About the Editor
Mrigakshi Dikshit Mrigakshi is a science journalist who likes to write about space exploration, biology, and technological innovations. Her works have been published in reputed publications like Nature India, Supercluster, The Weather Channel, Astronomy magazine, etc. If you have any suggestions, feel free to email her.
