In the next few years, everyone worldwide might experience a tiny time change: losing one second. Scientists say humans are causing this by melting ice at the poles, messing with the Earth’s spin and time.
Our days are set by how fast the Earth spins. But it’s not always the same speed; it can shift because of what’s happening on the planet’s surface and deep inside it. Sometimes, these tiny changes mean we need to adjust our clocks by adding or subtracting a second. It might sound small, but it’s a big deal for computer systems that need super accuracy.
“A negative leap second has never been added or tested, so the problems it could create are without precedent,” Patrizia Tavella, a member of the Time Department at the International Bureau of Weights and Measures in France, wrote in an article accompanying the study.
For the first time ever, scientists say we might have to take away one second. This could lead to problems we’ve never faced before, says Patrizia Tavella.
Global warming is playing a role in when this time change will happen. Melting ice is pushing back the moment we lose that second from 2026 to 2029. Understanding global warming helps predict these time changes, says Duncan Agnew, , professor of geophysics at the University of California San Diego and the study’s author.
“Part of figuring out what is going to happen in global timekeeping … is dependent on understanding what is happening with the global warming effect,” said Duncan Agnew.
Before 1955, a second was based on how long it took for the Earth to spin once. Then, we switched to atomic clocks, which are way more accurate. From the late 1960s, we’ve used coordinated universal time (UTC) to set our clocks. But because Earth’s spin isn’t constant, sometimes we need to adjust our clocks to match.
Long-term changes in Earth’s spin were mostly because of ocean tides. But now, melting ice, caused by humans burning fossil fuels, is also playing a big part.
It’s like a figure skater slowing down as they bring their arms down. The melting ice is causing Earth’s spin to slow too, in a way we’ve never seen before.
But there’s another twist in this time tale: what’s happening deep inside the Earth. The liquid core moves independently from the solid outer shell. If the core slows down, the outer shell speeds up to keep things in balance.
Scientists don’t know much about what’s happening deep down, but they know it’s making Earth spin faster overall. This means we might have to subtract a second soon.
“Nobody really anticipated that the Earth would speed up to the point where we might have to remove a leap second,” Agnew said.
Taking away a second might not seem like a big deal, but for computers that need to be super precise, it could cause problems. We might need to reprogram them, which could lead to mistakes.
“Being able to say so much ice has melted that it’s actually changed the rotation of the Earth by a measurable amount, I think gives you the sense, OK, this is a big deal.”
These findings show that changes in Earth’s core are having a bigger impact on our time than melting ice at the poles, which is a big surprise. While it might not affect most people, it’s a reminder of how humans are changing the planet.