VERSAILLES: International delegates approved the abolition of leap seconds on Thursday in France, setting May 20, 2027 as the start of a continuous global time standard.
The General Conference on Weights and Measures adopted a resolution allowing Coordinated Universal Time (UTC) to differ from Earth-rotation time by up to one hour. Delegates expect that limit to allow uninterrupted timekeeping for several centuries.
The decision addresses risks to computer systems that depend on precise synchronisation. Transport networks, electricity distribution, telecommunications and space projects all require continuous time, the resolution says.
Delegates cited the danger of a negative leap second, which would remove a second rather than add one. Timekeepers have never made that adjustment, and the conference warned that critical infrastructure remains largely unprepared.
Since 1972, timekeepers have added 27 leap seconds to reconcile atomic clocks with the planet’s uneven rotation, typically inserting the extra second at the end of June or December.
Technology companies including Meta, Google and Amazon have campaigned to end the practice. Meta engineers described each adjustment as “a major source of pain” for infrastructure operators in a July 25, 2022 engineering post.
Previous adjustments disrupted Reddit and LinkedIn in 2012. Cloudflare documented failures affecting some website requests on January 1, 2017, after the leap second inserted at the end of the previous year.
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The International Bureau of Weights and Measures (BIPM), which produces UTC, has responsibility for supporting implementation. BIPM will work with international organisations to inform users and continue monitoring the difference between atomic time and Earth-rotation time.
