Climate shift extends day‑length and alters Earth's rotation

Scientists from the Swiss Federal Institute of Technology in Zurich (ETH) have determined that under the influence of climate warming, water from glaciers moves towards the equator, causing a day-lengthening calculated in milliseconds.

"This means that there is a change in mass distribution, which in turn affects the Earth's rotation," emphasizes Prof. Benedikt Soja, the author of the study described in the "Proceedings of the National Academy of Sciences."

"It's like a figure skater doing a spin - first, with arms close to the body, and then extended," illustrates the specialist. Fast spins slow down because the mass moves away from the axis of rotation. This results from the physical principle known as the conservation of angular momentum. The same law applies to the Earth's rotations, which determine the length of the day. Although the changes are not significant, calculated in milliseconds, over time, they should surpass the slowdown resulting from ocean tides that have been acting for billions of years.

Moreover, as the researchers showed, the mentioned changes in mass distribution also cause a shift in the Earth's axis of rotation. It has already been demonstrated that the points of this axis shift by about 10 metres every hundred years. Until now, it was thought this was due to processes inside the Earth. Now, however, scientists have shown for the first time how much this axis shift is determined by the movement of water from glaciers.

"For the first time, we present a comprehensive explanation of the reasons for long-term changes in the Earth's axis of rotation. In other words, we now know why and how this axis moves relative to the Earth's crust," explains Prof. Soja.

This is not the end of the scientists' findings. The analysis also showed that the migration of water and processes occurring inside the Earth interact with each other.

"Climate change causes a shift in the Earth's axis of rotation. It turns out that due to the conservation of angular momentum, there are changes in the dynamics of the Earth's core," explains Prof. Soja.

The effects are minimal, however, and the scientists assure us there is no reason to be concerned about human functioning. However, they may be significant, for instance, for space flights.

The researchers explain that even a slight deviation in the trajectory over such a large distance can cause a significant miss of the target, for example, when sending a probe to another planet.

The latest advancements in computer science helped the researchers in their findings. They used artificial intelligence trained to utilise the laws of physics and the phenomena occurring on Earth.