CGPM approves resolution to end leap second adjustments to UTC

The General Conference on Weights and Measures (CGPM) has approved Resolution 5, which establishes significant changes to the maintenance of Coordinated Universal Time (UTC). The decision, made during the 28th meeting in Versailles, France, aims to ensure the long-term continuity of UTC by ending the practice of periodic adjustments via leap seconds.

Currently, leap seconds are used to align UTC, which is based on high-precision atomic clocks, with UT1, which is based on the Earth's rotation. Because the Earth's rotation is inconsistent, these manual adjustments are required. However, these adjustments can cause synchronization errors in critical digital infrastructures, including telecommunications, energy distribution, transportation, and space projects.

Under the new resolution, which is set to take effect on May 20, 2027, the maximum allowable difference between UT1 and UTC will be increased to 3,600 seconds (one hour). This change is intended to provide a stable, continuous time scale for at least a century, preventing the technical inconsistencies associated with sudden one-second shifts.