Climate change is slowing the Earth’s rotation and the way in which we measure time may need to change, a study has found.

Synchronised global timekeeping is crucial for maintaining the accuracy of various technologies, from smartphones to computer networks.

Currently, leap seconds are added roughly every two to three years to help align atomic clocks with the Earth’s irregular rotation. In 1972, a day defined by the Earth’s rotation was 0.0025 seconds (2,500 microseconds) longer than the one defined by atomic clocks. Over the course of a year, the accumulated difference was almost a second, so a leap second was used to keep the difference from getting any larger. But in 2023, the two kinds of day differed by only 80 microseconds, so the difference in time over a year added up to only 0.03 seconds.

Researchers at Scripps Institution of Oceanography at UC San Diego warn that within the next decade, a negative leap second – or a minute lasting only 59 seconds – might become necessary due...