Man slows Earth's rotation and makes it wobble: here's how

The rotation of the Earth and its orientation are being disrupted by human-induced climate change, according to new research.

The changes might seem imperceptible, but they could lead to significant consequences, such as the introduction of negative leap seconds, interferences with space travel, and alterations in the Earth's inner core.


Currently, a day on Earth lasts about 86,400 seconds, but various factors can cause this duration to vary by a few milliseconds each year. Besides tectonic plate movements and the Moon's gravitational influences, anthropogenic climate change is playing an increasingly significant role in these variations.

For several decades, polar ice melt, particularly in Greenland and Antarctica, has been accelerating due to global warming. This additional water accumulates near the equator, causing the Earth to bulge slightly and slow its rotation. This phenomenon is similar to ice skaters slowing down when they extend their arms.

A recent study, published in PNAS, used advanced artificial intelligence combining real data and physical laws to predict the evolution of the Earth's rotation. The results confirm a previous study from March, suggesting a lengthening of earthly days, but with more precise estimates.

The research team also published a study in Nature Geoscience, showing that the accumulation of water near the equator shifts the Earth's rotational axis, causing the magnetic poles to wobble. This study suggests that this phenomenon will intensify in the coming years.

Earth's days have always varied in length. A billion years ago, a day lasted about 19 hours. In 2020, the Earth was rotating faster than it had since 1960, before slowing down again in 2021. Lunar tidal friction is primarily responsible for this millennial slowdown, but current climate change could become the main factor by the end of the century.

The elongation of days might necessitate the introduction of negative leap seconds by 2029 to compensate for the accumulated lengthening of days. This could disrupt the synchronization of electronic devices, although some researchers downplay this risk. These changes must also be considered for space navigation, especially when sending probes to other planets.

The team warns that changes in the Earth's rotational axis could also influence the inner core, but the potential interactions remain poorly understood.