The short version
- The BIPM voted to eliminate leap seconds by May 2027, moving the deadline forward from the previously agreed-upon 2035 target.
- The acceleration aims to prevent infrastructure failures that could occur if timekeepers were required to subtract a second rather than add one.
- Major technology firms have supported the change after previous leap seconds caused significant outages for platforms like Reddit and LinkedIn.
A fundamental shift in global timekeeping is set to take effect earlier than originally planned, as international standards bodies move to eliminate the practice of inserting leap seconds into atomic clocks. The International Bureau of Weights and Measures (BIPM) voted on Thursday to discontinue the ad hoc adjustments that have long been used to keep coordinated universal time aligned with the Earth’s irregular rotation. While members had previously agreed in 2022 to cease using leap seconds no later than 2035, the new decision expedites this transition significantly. The changes are scheduled to take effect on May 20 of next year, a date chosen to coincide with World Metrology Day.
The primary driver for accelerating this timeline is a growing concern regarding the stability of critical digital infrastructure. Historically, leap seconds have involved adding an extra second to the clock to compensate for the Earth’s slowing rotation. However, recent shifts in planetary dynamics suggest that timekeepers may soon need to subtract time rather than add it to maintain synchronization between astronomical and atomic standards. This scenario presents a unique technical challenge because the subtraction of a second has never been attempted in modern timekeeping history.
Experts warn that introducing a negative leap second could trigger widespread disruptions across systems that rely on precise time synchronization. The fear is not merely theoretical; past implementations of positive leap seconds have already demonstrated their potential to destabilize digital networks. Several major technology platforms, including Foursquare, Reddit, LinkedIn, and Yelp, have experienced service outages in previous years when leap seconds were added. These incidents highlighted the fragility of software systems that are not designed to handle unexpected changes in time progression.
The tech industry has largely welcomed the move to abolish leap seconds entirely. Companies such as Meta, Google, Microsoft, and Amazon have publicly supported efforts to scrap the current system. For these organizations, the reliability of their global infrastructure depends on consistent timekeeping protocols that do not require sudden, manual adjustments. The removal of leap seconds eliminates the risk of software errors associated with both adding and potentially subtracting time units, thereby reducing the likelihood of cascading failures in cloud services and financial trading platforms.
Under the new framework, atomic time and astronomical time will be allowed to drift apart gradually rather than being forced into alignment through frequent adjustments. Instead of inserting seconds, the revised system may eventually utilize larger intervals, such as leap hours, to reconcile the difference between the two time standards. However, this divergence is expected to occur very slowly. It is estimated that it could take approximately 3,000 years before an entire hour needs to be added to bring the systems back into rough alignment.
This transition marks a significant departure from decades of timekeeping tradition. The leap second was introduced to ensure that civil time remained closely tied to the position of the sun and the Earth’s rotation. By abandoning this practice, authorities are prioritizing the stability of digital infrastructure over strict astronomical correspondence. This shift reflects the increasing importance of atomic precision in modern society, where nanosecond-level accuracy is crucial for telecommunications, navigation systems, and data synchronization.
The decision by the BIPM underscores a broader trend toward simplifying complex technical standards to mitigate risk. The comparison to the Y2K bug scare highlights the potential severity of time-related infrastructure failures. Just as organizations worldwide rushed to update computer systems to handle the millennium rollover, the tech sector is now adapting to a new era of timekeeping that removes the need for periodic manual interventions. This proactive approach aims to prevent future crises before they can emerge.
As the implementation date approaches, software developers and system administrators will need to prepare their infrastructure for the change. Although the removal of leap seconds simplifies certain aspects of time management, it requires updates to protocols that currently account for these adjustments. The transition period will likely involve careful coordination among international bodies, technology companies, and government agencies to ensure a smooth shift without disrupting global services.
The long-term implications of this change extend beyond immediate technical concerns. By allowing atomic and astronomical time to drift, society is accepting a gradual decoupling of civil time from natural cycles. While this may seem abstract to the general public, it represents a fundamental redefinition of how humanity measures and manages time in an increasingly digital world. The stability gained from eliminating leap seconds comes at the cost of losing a direct link between our clocks and the Earth’s rotation.
Looking ahead, the success of this new system will depend on its ability to maintain synchronization across diverse global networks without the safety valve of leap seconds. The three-millennium horizon for the next major adjustment suggests that current generations need not worry about immediate astronomical misalignment. However, the precedent set by this decision may influence how future technological standards are developed, emphasizing resilience and simplicity over strict adherence to natural phenomena.
Sources behind this briefing
Go to the original reporting
- The Verge↗Time is a-changin’: say goodbye to the leap second
