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Story summary
- International timekeeping authorities will vote at the 2026 CGPM to adopt a leap-hour system that would begin in 2027.
- Scientists warn that a negative leap second could trigger unknown and potentially catastrophic infrastructure problems.
- Adding a leap second has caused outages at Meta, Reddit, Cloudflare, grounded planes, and disrupted high-frequency trading.
- Patrizia Tavella says a 10 % risk of a negative leap second is unacceptable, prompting the leap-hour push.
