Scientists Consider Replacing Leap Seconds with a Century-Scale 'Extra Hour' to Protect Global Digital Infrastructure from Negative Leap Second Risks
International timekeeping authorities are accelerating plans to overhaul the leap second system by allowing a much larger gap between atomic time and Earth's rotation, potentially requiring the next major adjustment only after several centuries. The proposal, which could take effect as early as 2027, aims to eliminate the disruptive practice of adding or removing individual seconds from UTC. Leap seconds, introduced in 1972, have repeatedly caused outages at companies including Meta, Reddit, and Cloudflare, while also affecting aviation and high-frequency trading. Because Earth's rotation has been accelerating since 2016, experts now face the unprecedented risk of a negative leap second that would remove one second from UTC—an event whose impact on modern systems remains unknown. With a roughly 30 percent chance of needing such a negative adjustment before 2035, the General Conference on Weights and Measures is pushing for a larger tolerance between coordinated and astronomical time. The new approach would preserve the long-term link between civil time and Earth's rotation but make it far less rigid, allowing atomic clocks to govern daily operations without sudden one-second jumps.
securitylab_n•Other
