Timekeepers are meeting on October 15, 2026, near Paris to discuss the potential elimination of the leap second, which is currently used to keep clocks synchronized with the Earth's rotation. The leap second has been added periodically since 1972, with the last addition occurring on December 31, 2016. The need for leap seconds arises from the Earth's rotation being less precise due to its gradual slowing over time.
The International Bureau of Weights and Measures (BIPM) voted in 2022 to consider scrapping the leap second by 2035, although some countries, including Russia, have proposed delaying the implementation until 2040. The meeting in Versailles will address three proposals: the accuracy of atomic clocks versus optical frequencies, the potential elimination of the leap second, and synchronizing time measurements on Earth with a new time standard being developed by NASA for the moon.
If the leap second is eliminated, clocks will no longer be aligned with the Earth's rotation, leading to a gradual increase in the discrepancy between the two. By 2100, clocks could be ahead of the Earth by 54 seconds, and this gap could widen to several hours over the next two millennia. While scientists indicate that human routines will not be affected, the change may lead to sunrise and sunset times becoming misaligned with natural rhythms.
The BIPM meeting will determine the future of the leap second and its implications for timekeeping worldwide.