Clock ticking for leap second: Why timekeeping could change forever

What the report says

Timekeepers from around the world are meeting near Paris on Thursday to consider whether to end the leap second, a correction used since 1972 to keep Coordinated Universal Time aligned with the Earth’s slowly changing rotation. Al Jazeera reports that the debate comes as the current system, based on atomic clocks, increasingly diverges from the planet’s uneven spin.

The article says the leap second was introduced to reduce that gap, with the last one added in 2016. But the practice has drawn criticism from companies and institutions that need highly precise timekeeping, including financial markets, data centers and software systems. Al Jazeera notes that previous leap seconds have been linked to technical disruptions, helping drive calls for a simpler global standard.

The meeting is being held by the International Bureau of Weights and Measures, or BIPM, whose member states are weighing three related proposals: whether to redefine the second using newer optical-frequency technology, whether to eliminate leap seconds, and whether to coordinate Earth time with a lunar time standard under development by NASA. Al Jazeera says proposals approved at the meeting could take effect in 2027.

If leap seconds are abolished, clocks would gradually drift further from Earth’s rotation over time. The article says the practical effect on daily life would likely be small at first, but long-term differences would eventually become more noticeable, affecting the relationship between clock time and sunrise and sunset.