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Time’s up: the leap second is being scrapped

Time’s up: the leap second is being scrapped


The ad hoc time correction will end after causing years of disruption to tech infrastructure. But not until 2035.

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A photo taken on October 19th, 2021, shows the landmark Television Tower (Fernsehturm, L) and the World Time Clock (Weltzeituhr) in Berlin.
Leap seconds depend entirely on how quickly the Earth spins, which can be a nightmare for managing technology hardware infrastructures. (Pictured: the World Time Clock in Berlin.)
Photo by INA FASSBENDER/AFP via Getty Images

A global panel of scientists and government representatives have voted to scrap leap seconds by 2035. The ad hoc time adjustment is occasionally inserted to account for the gradual slowdown of the Earth’s rotation and has caused headaches for numerous tech companies over the years.

The leap second was introduced in 1972 as a way to adjust Coordinated Universal Time (UTC) roughly every 21 months. As these seconds are irregular and hard to predict due to the varying speed of the Earth’s rotation, they can disrupt systems that require precise timekeeping. Meta published a blog post earlier this year calling for leap seconds to be scrapped, highlighting that Reddit went down for around 40 minutes back in 2012 when a new leap second interfered with the company’s servers. In 2017, Cloudflare blamed the leap second for its DNS service going down on New Year’s Day, precisely at midnight UTC.

As reported by The New York Times, member states of the International Bureau of Weights and Measures almost unanimously voted in support of Resolution D at a meeting in Versailles, France, on Friday. Resolution D calls for UTC to go uninterrupted by leap seconds from 2035 until at least 2135, during which it’s hoped that scientists can develop a better system for keeping atomic and astronomical time scales in sync.