终于要实现了：国际计量大会似乎即将废除闰秒制度，以期实现全球时间计量的一致性。自1972年以来，为让协调世界时（UTC）与基于地球自转变化而确定的天文时间尺度UT1保持同步，人类共添加了27个闰秒。此次提案提议将UTC与UT1之间允许的最大偏差从0.9秒提高至1小时，如此一来便可数个世纪内都无需再进行闰秒调整。
It's about time: the General Conference on Weights and Measures looks set to end leap seconds in an effort to reach horological harmony. Since 1972, 27 leap seconds have been added to Coordinated Universal Time (UTC) to keep it in step with the astronomical time scale UT1, which is based on Earth's fluctuating rotation. The proposal would increase the permitted difference between UTC and UT1 from 0.9 seconds to one hour, avoiding leap-second adjustments for centuries.
近年来地球自转速度有所加快，这增加了出现“负闰秒”的可能性——即减少1秒而非增加1秒。这种操作此前从未实施过。据专家估算，到2035年全球系统需要执行负闰秒操作以保持两种时间尺度同步的概率约为30%。对于那些仅能处理增加秒数而无法应对秒数减少情况的计算机系统而言，这可能会引发诸多问题。目前许多国家级计量机构均支持该提案，预计其将获得通过。
Earth's rotation has also sped up in recent years, raising the possibility of a negative leap second – removing a second rather than adding one. That has never been done before. Experts have estimated a 30 percent probability that global systems will need a negative leap second by 2035 to keep the two time measures in step. That could pose problems for computer systems designed to handle added seconds but not removed ones. Many national bodies support the proposal, which is expected to pass.
若获批准，相关变更将于2027年5月20日正式生效。英国国家物理实验室首席科学家塞特南·谢马尔指出，该提案能在数个世纪内规避与闰秒相关的各类风险。“闰秒的实施难度较大且难以确保万无一失；一旦操作不当，便可能导致不同网络间出现时间偏差，进而引发移动电话网络或电网等系统的故障。若首次实施负闰秒，此类风险还将进一步升高。”
If approved, the change would take effect on May 20, 2027. Setnam Shemar, principal scientist at the UK's National Physical Laboratory, said the proposal would avoid the risks associated with leap seconds for centuries. "Leap seconds can be difficult to implement reliably, and if not applied correctly, they can cause differences in time across networks, potentially leading to the failure of systems such as mobile phone networks or electricity grids. These risks could increase if a negative leap second had to be implemented for the first time.
他补充道：“此前为让协调世界时与UT1的偏差维持在0.9秒以内，我们需定期添加闰秒；而从2027年5月20日起，两者间的偏差在达到1小时之前都无需进行调整，这能确保协调世界时的稳定性延续数个世纪之久。对于天文学及天体导航等应用领域而言，协调世界时与UT1之间的关系至关重要。”
"Previously, leap seconds were added to UTC to keep it within 0.9 seconds of UT1. From 20 May 2027, a difference of up to 1 hour will be allowed before intervention is needed, ensuring the continuity of UTC for several centuries or more. "The relationship between UTC and UT1 is important for some applications, such as astronomy and celestial navigation.
这一决定并不会切断这种联系：UT1仍会受到持续监测，其与协调世界时（UTC）的偏差信息也会继续通过现有的国际服务进行发布。®
The decision would not sever that link: UT1 will continue to be monitored, and its difference from UTC will continue to be disseminated through established international services." ®