Melting polar ice is messing with global timekeeping

Human-caused "global warming is managing to actually measurably affect the rotation of the entire Earth"

(Image credit: Jeff J Mitchell / Getty Images)

published 28 March 2024

What happened

So much polar ice is melting and flowing toward the equator that it's influencing how fast the Earth spins, complicating global timekeeping, said a paper published in Nature on Wednesday.

The Earth's rotation slowed for a long period, prompting authorities measuring time by the Earth's rotation — astronomical time — to add occasional "leap second[s]" to sync up with coordinated universal time (UTC), the atomic-clock-based standard since the 1960s, CNN said. But now the planet is spinning faster, necessitating subtracting a second. Agnew said this unprecedented "negative leap second" can wait until 2029, not 2026, due to the slowing effect of rising ocean levels.

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Peter has worked as a news and culture writer and editor at The Week since the site's launch in 2008. He covers politics, world affairs, religion and cultural currents. His journalism career began as a copy editor at a financial newswire and has included editorial positions at The New York Times Magazine, Facts on File, and Oregon State University.