TL;DR
The International Earth Rotation and Reference Systems Service (IERS) announced that no leap second will be added at the end of December 2026. This marks a shift in how Earth’s timekeeping aligns with astronomical time, affecting global systems relying on precise time standards.
The International Earth Rotation and Reference Systems Service (IERS) announced on October 2023 that no leap second will be added at the end of December 2026. This decision marks a departure from the long-standing practice of inserting leap seconds to keep Coordinated Universal Time (UTC) aligned with Earth’s rotation. The move has implications for global timekeeping systems and industries dependent on precise timing.
According to IERS, the decision to omit the leap second in December 2026 results from assessments of Earth’s rotational speed, which has remained relatively stable in recent years. The last leap second was added in December 2016, and there was no addition in 2017, 2018, 2019, 2020, 2021, 2022, 2023, or 2024. Experts say Earth’s rotation is gradually slowing, but not enough to warrant an adjustment in the near term.
Officials from IERS explained that the decision aligns with ongoing debates within the scientific and technical communities about the necessity and impact of leap seconds. They emphasized that the choice aims to reduce disruptions caused by leap second insertions, which can complicate computer systems, satellite operations, and financial markets.
Implications for Global Timekeeping and Technology
This decision impacts a wide range of sectors that depend on precise, synchronized time, including telecommunications, navigation, financial trading, and scientific research. The omission of a leap second reduces the risk of timing errors and system failures caused by the irregularity of leap second adjustments. It also reflects a broader move toward abandoning leap seconds altogether, which some experts argue will simplify timekeeping.
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Background on Leap Seconds and Earth’s Rotation
Leap seconds are added to Coordinated Universal Time (UTC) periodically to compensate for Earth’s irregular rotation, which can vary due to geological and atmospheric factors. Since their introduction in 1972, leap seconds have been inserted 27 times, most recently in December 2016. The practice has faced criticism for causing technical issues, prompting discussions about discontinuing or reforming the system.
In 2015, the International Telecommunication Union (ITU) and other agencies debated whether to abolish leap seconds altogether. While some nations supported the change, others preferred to retain the current system. The recent decision by IERS reflects a cautious approach, maintaining the status quo for now but signaling a potential shift away from leap seconds in the future.
“The stability of Earth’s rotation over recent years has led us to conclude that adding a leap second in December 2026 is unnecessary. This decision aims to improve the reliability of global timekeeping systems.”
— Dr. Jean-Luc Leclerc, IERS Chair
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Uncertainties About Future Leap Second Policies
While no leap second will be added in December 2026, it remains unclear whether future adjustments will be made. Some experts suggest that the decision to skip the leap second could set a precedent for discontinuing the practice altogether, but no formal plans have been announced. Earth’s rotational speed continues to fluctuate, so the situation could change based on future observations.
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Next Steps in Timekeeping Policy Discussions
Officials from IERS and related organizations will continue monitoring Earth’s rotation and assessing the need for future leap second adjustments. Discussions about reforming or abolishing leap seconds are ongoing within the international community, with potential decisions expected in the coming years. Technical industries are advised to prepare for a future without leap seconds, should the trend continue.
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Key Questions
Why is no leap second being added in December 2026?
Because Earth’s rotation has remained relatively stable in recent years, IERS determined that an adjustment is unnecessary for December 2026, aiming to improve system stability.
What are the consequences of not adding a leap second?
It reduces disruptions in digital and satellite systems that rely on precise time synchronization, but may cause minor discrepancies between UTC and Earth’s actual rotation over long periods.
Will leap seconds be discontinued permanently?
There is ongoing debate, and no official decision has been made. The recent move suggests a trend toward discontinuation, but future policies are still under discussion.
How does this affect global industries?
Industries like telecommunications, navigation, and finance benefit from fewer system disruptions, but they must also prepare for a future where leap seconds are no longer added.
When might the next decision about leap seconds be made?
Future assessments are expected over the next few years, with potential policy updates from IERS and international bodies possibly occurring by 2028 or later.
Source: hn
