Melting ice changes the speed of the Earth’s rotation: how much time will people save?

The leaping second will be abolished no later than 2040

The melting of ice masses at the poles and the resulting change in the shape of the globe led to a change in the speed of rotation of the Earth. So say experts from the Scripps Institution of Oceanography in California, whose article was recently published in the journal Nature. Since there is speculation that the Earth’s rotation rate is increasing, the traditional addition of a second to UTC may be abandoned.

The speed of rotation of our planet around its axis is uneven. Until recently, it slowed down a little, and this required periodic “twisting” of the reference, atomic earth clocks, as the natural ones accumulated an additional second as a result of the slowdown. This happened once every few years.

According to one theory, the slowdown of the natural course of the Earth was facilitated by lunar ebbs and flows, the gravitational influence of other planets, and earthquakes.

In 2022, the Earth’s rotation, on the contrary, unexpectedly accelerated. According to one version, which scientists at the Scripps Institution of Oceanography insist on, this happened due to the melting of ice, as a result of which the planet changed its shape: it became flatter at the poles and more convex at the equator.

Now the “time keepers” of different countries are thinking about the need for the traditional addition of an additional second. Recommendations were even made to introduce a moratorium on the movement of seconds in any direction.

As metrologist physicist Vitaly Palchikov previously explained to MK, the melting of ice at the poles is still considered by many only as a version of the influence on the speed of rotation of the planet. Most likely, he said, global warming should lead to a slowdown in the Earth’s rotation due to an increase in the moment of inertia.

There is another common hypothesis that the speed of rotation of the Earth is influenced by its solid core. It has a fairly large mass, rotates in the opposite direction, which means it can lead to acceleration or deceleration of the Earth’s rotation around its axis. However, as Palchikov explained, calculations that take into account the ratio of the Earth’s core and mass show that this version is also not confirmed.

As for the question of the additional second, which would have to be translated forward or backward, depending on the accumulated acceleration or lag of the Earth from the atomic clock, they decided to abandon it. At the International Bureau of Weights and Measures conference in November 2022, almost all experts were unanimous. The legally binding Telecommunications Union decided a few months ago to abandon the leaping second, “from 2035 but not later than 2040.” That is, all of us in the future will have a continuous time scale.

By the way, the only country that voted against abandoning the leaping second was Russia. The fact is that many types of equipment, for example satellites in orbit, are designed for long-term use, and a transition to another mode of their operation may lead to the need for earlier replacement.