The decision was made by representatives from governments worldwide at the General Conference on Weights and Measures (CGPM) outside Paris on 18 November. It means that from 2035, or possibly earlier, astronomical time (known as UT1) will be allowed to diverge by more than one second from coordinated universal time (UTC), which is based on the steady tick of atomic clocks. Since 1972, whenever the two time systems have drifted apart by more than 0.9 seconds, a leap second has been added.

Leap seconds aren’t predictable, because they depend on to Earth’s natural rotation. They disrupt systems based on precise timekeeping,

Future metrologists might find more elegant ways than the leap second to realign UTC and UT1.

https://doi.org/10.1038/d41586-022-03783-5