Human activities are changing Earth's spin so much that it might affect how we keep time

• Polar ice melt driven by climate change is affecting Earth's rotation, according to new research.
• We may have to adjust timekeeping by "skipping" a second in 2029.

The climate crisis has gone so far that it's altering the shape and spin of our planet, and changing our experience of time itself, according to a new study published in the journal Nature on Wednesday.

"Enough ice has melted to move sea level enough that we can actually see the rate of the Earth's rotation has been affected," Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography and author of the study, told Nature.

Don't worry — this change in Earth's rotation won't be catastrophic. However, it does mean that we'll have to adjust our time keeping, which may be a problem for much of the computing we rely on.

Ice melt could delay the dreaded negative leap second

Humans track time in seconds, minutes, and hours, and these measurements are dictated by Earth's rotation on its axis and the sun's position in the sky — what's called the solar timescale.

But the solar timescale is not very precise because the planet's spin has never been constant — it changes based on how fluids both above and below the crust move.

Therefore, humans invented a more precise way of time keeping with atomic clocks and the atomic timescale.

But, every 1.5 years, or so, on average, these two timescales misalign because of the Earth's inconsistent rotation rate. When that happens, we accommodate with what's called a leap second: a second that is added to the atomic timescale to realign it with the solar timescale.

We've been adding leap seconds this way since 1972, but we haven't needed one since 2016.

That's because Earth has spun faster and faster over the last eight years for reasons scientists are still trying to understand.

As a result, scientists predict that we would need the first-ever negative leap second by 2026. Meaning we'd need to subtract a second from the atomic timescale, instead of adding one.

But this new research suggests that climate change is slowing down the acceleration of Earth's rotation and will delay that negative leap second to 2029.

Losing one second of time may not sound like much. But adding and subtracting leap seconds poses big problems for computing, so much so that the International Bureau of Weights and Measures voted to get rid of them by 2035.

Computers, financial exchanges, GPS, and spaceflight rely on extremely precise timekeeping, so leap seconds can lead to "serious malfunctions in critical digital infrastructure," the Bureau wrote in its resolution. It added that the negative leap second which may soon be necessary "has never been foreseen or tested."

"We do not know how to cope with one second missing. This is why time metrologists are worried," Felicitas Arias, former director of the Time Department at the International Bureau of Weights and Measures, told Nature.

While Agnew's study suggests we have more time before facing this worrying unknown, it's worth noting that Earth's spin is very difficult to predict, and the new study is not necessarily a definitive forecast.

"There's a very great uncertainty about this," Judah Levine, a physicist at the National Institute of Standards and Technology, told The Washington Post. "A few years ago, there were predictions in the other direction."

How melting ice slows Earth's spin

There are three main mechanisms that control the Earth's spin:

• One is tidal friction, or the interaction between moving ocean water and the ocean floor, which slows Earth's rotation.

• The second is changes in the ice caps that covered Northern Canada and Scandinavia during the last Ice Age, which made Earth more spherical, speeding up its rotation rate, according to Agnew.

• And finally, currents of magma inside Earth's spinning, liquid core change irregularly, causing it to rotate faster or slower and altering the entire planet's rotation in the process.

But now, a fourth influence has come to scientists' attention: climate change.

As average global temperatures rise, polar ice is melting at an unprecedented rate, dumping water in the oceans. As that meltwater moves from the Arctic toward the equator — a process that is raising sea levels and causing devastating coastal flooding — our planet grows slightly wider around the middle, which slows its rotation.

Picture a figure skater spinning with her arms above her head. Now imagine that she lowers her arms to extend them out at her sides, causing her spin to slow down. Earth's widening equator is having a similar effect on its spin.

"To me, the fact that human beings have caused the rotation of the Earth to change is kind of amazing," Agnew told CNN.

Perhaps you've managed to escape the mega-clouds of wildfire smoke, historic floods, and debilitating heat waves so far. But this new study reveals that the climate crisis is affecting even the most intimate aspects of our day-to-day lives. Nobody escapes time.