Melting glaciers will shorten Earth’s year by 2029

Faster melting of glaciers in Greenland and Antarctica may be the reason for the Earth’s angular velocity to further decrease. For this reason, there may be a need to remove leap seconds after three years.

The astronomical year, that is, the period during which the Earth makes a complete revolution around its axis, does not coincide with the calendar year. This is especially reminiscent of leap year, when there is an extra day every fourth February. The reason for this phenomenon is that the planet’s rotation rate is not constant and each subsequent day is slightly different from the previous one.

Scientists monitor the change in Earth’s rotation rate (angular velocity) to synchronize the calendar year with the astronomical year. In addition, they reveal the reasons affecting the “behavior” of the planet: this is necessary to predict its subsequent rotation rate and the imminent need to adjust Coordinated Universal Time (UTC).

UTC is “set” using so-called leap seconds. When the calendar deviates from the actual rotation rate of the Earth, a second is added to the year or vice versa subtracted from it (negative leap second). According to current calculations, a negative leap second will be needed for the first time in 2026. But a new study shows that could happen three years later because glaciers in Greenland and Antarctica are melting faster. The relevant scientific article was published by the journal. Nature.

A researcher from the University of California, San Diego analyzed existing data and predictions about the Earth’s rotation. If it is assumed that the angular velocity of the molten core of the Earth has decreased at a constant rate in recent years (the angular velocity of the remaining part, which is the solid part of the planet, has increased) and this regularity is projected into the near future, it turns out that the leap second should be subtracted from 2026. However, the scientist noted that the Earth’s rotation rate is decreasing faster than before due to global warming and increased melting of glaciers in Greenland and Antarctica. Using mathematical modeling, the author of the paper found that at the new speed, negative leap seconds may not be needed until 2029.

The results of the scientist’s study indicate that the policy for regulating UTC will have to be adjusted earlier than expected due to changes in the “behavior” of the Earth. Since it turns out that global warming and the rotation of the planet are most closely related, the impact of the first process on the second process should continue to be monitored in the future.

Changing the speed at which the Earth rotates can cause problems in many fields, such as distributed computing and financial markets, because these require a precise and standardized time scale. Leap seconds are inconvenient because it is impossible to program their accounting in advance: they are introduced based on existing observations of the Earth’s rotation rate. At the same time, only seconds were added before, and the possible consequences of such an unprecedented subtraction are still unknown.