Over the years, human activities have had little effect on Earth’s motions, namely its rotational speed and axis.
These motions are governed primarily by the Moon’s gravity and internal processes in the core and mantle.
But now, melting glaciers due to human activities are confusing with these natural movements.
A new study reveals that Earth’s spin axis is “shifting” due to climate change and the planet’s internal dynamics.
Researchers at ETH Zurich have used sophisticated AI models to better understand polar motion, the movement of the Earth’s spin axis relative to the crust.
The study predicts that if greenhouse gas emissions continue to rise, they will eventually outweigh the long-term influence of the moon’s tidal force. For billions of years, the Moon has determined the constant length of our days.
“We as humans have a greater impact on our planet than we realize. This naturally places a great responsibility on us for the future of our planet,” said Benedict Soja, professor of space geography at the Department of Civil, Environmental and Geological Engineering at ETH Zurich.
Extending the days
Two recent studies have examined a surprising connection between melting ice caps, the planet’s wobble, and the length of our days.
Melting ice at the poles redistributes mass toward the equator, slowing Earth’s rotation. Water travels from the poles to the equator, upsetting the Earth’s balance.
As ice melts on Earth’s surface, it slows the planet’s rotation and lengthens the day. Research from ETH Zurich shows that inertia lengthens our days slightly, by a few milliseconds – compared to the usual 86,400 seconds.
In physics, there is a law called conservation of angular momentum. It basically says that a rotating object wants to keep rotating at the same rate unless forced to change it. Earth’s rotation also follows this rule. Melting ice redistributes the mass, and this change, according to law, slows down the rotation of the Earth.
“This means mass transfer is taking place, which affects the Earth’s rotation,” Soja explained.
Impact on Earth’s core
The researchers also studied why and how the Earth’s axis moves gradually over long periods of time. The team used physics-informed neural networks to create the most detailed model to date, explaining how climate in the Earth’s core, mantle and surface contribute to polar motion.
Both studies highlight the complex web of interactions within Earth. Events at the surface, such as ice melting, can have deep effects at the core, and vice versa.
“Climate change causes Earth’s axis of rotation to shift, and the feedback of conservation of angular momentum also changes the dynamics of Earth’s core,” Soja explained.
As the polar ice melts, the resulting water moves from the poles toward the equator, causing the Earth to rotate slowly. In total. Benedict Soja explained that the phenomenon is similar to a figure skater, who spins slowly as she extends her arms. The same principle applies to the Earth’s rotation.
“Current climate change may affect even deep Earth processes and reach larger scales than previously thought,” said Giani Shawanti, lead author of the study and PhD student. Press release.
About the editor
Mrigakshi said Mrigakshi is a science journalist who likes to write about space exploration, biology and technological innovations. His work has appeared in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy Magazine. If you have pitches in mind, please feel free to email her.
