Just when you thought climate change was only reshaping coastlines and weather patterns, a new scientific study reveals an even more startling impact: Earth’s days are literally getting longer. According to recent research, the planet’s spin is slowing down at a rate not seen in millions of years. This subtle but unprecedented slowdown is rewriting what we thought we knew about our world’s dynamics — and it could have surprising consequences for everything from timekeeping systems to how we understand our planet’s future. Curious how tiny milliseconds could tell such a big story? Read on to uncover the science behind the slowdown.
Climate change is slowing down Earth’s spin
Scientists in Austria and Switzerland have used ancient climate data—specifically how sea levels have shifted since the Late Pliocene—to calculate exactly how fast the Earth’s rotation is changing. Their findings are startling: between the years 2000 and 2020, our days lengthened by approximately 1.33 milliseconds per century. This marks the most dramatic slowdown of the Earth’s spin since the era when prehistoric mastodons and saber-toothed cats roamed the planet.
This shift isn’t just a natural quirk; it’s a direct consequence of our changing environment. As the planet warms, melting ice caps redistribute water toward the equator.
The researchers emphasize that this isn’t just a minor statistical blip. According to the study’s coauthor, Benedikt Soja, a professor of space geodesy at ETH Zurich: “This rapid increase in day length implies that the rate of modern climate change has been unprecedented at least since the late Pliocene, 3.6 million years ago.”
The speed of this change points to one clear culprit. Soja notes that: “The current rapid rise in day length can thus be attributed primarily to human influences.”
The ‘figure skater’ effect: How oceans slow the Earth
In a recent study published in the Journal of Geophysical Research: Solid Earth, researchers describe a phenomenon known as “continental-ocean mass redistribution.” This is a fancy way of saying that as polar ice sheets and mountain glaciers melt, that water doesn’t stay put—it flows toward the wider, middle section of our planet near the equator.
This extra weight at the Earth’s “waistline” creates a physical drag that slows down our planet’s rotation. To make this easier to visualize, study coauthor Mostafa Kiani Shahvandi compares the Earth to a figure skater: “A figure skater who spins more slowly once they stretch their arms, and more rapidly once they keep their hands close to their body.”
By pumping water from the poles to the equator, we are essentially forcing the planetary “figure skater” to reach her arms out. While Earth’s speed has fluctuated naturally over millions of years, the current shift is nearly unprecedented. According to Kiani Shahvandi, a researcher at the University of Vienna:
“Only one time—around 2 million years ago—the rate of change in length of day was nearly comparable, but never before or after that has the planetary ‘figure skater’ raised her arms and sea levels so quickly as in 2000 to 2020.”
Why a few milliseconds are a big deal
It might sound like a tiny shift, but adding a few milliseconds to the day creates a temporal drag that ripples through our most advanced technologies. Our modern world—from the GPS on your phone to satellite communications—depends on Earth’s physical rotation staying perfectly in sync with ultra-precise atomic clocks. When the planet slows down, that synchronization slips, potentially leading to errors in location tracking and data timing.
As Soja explains, “Even though the changes are only milliseconds, they can cause problems in many areas, for example, in precise space navigation, which requires accurate information on Earth’s rotation.”
Source: Gizmodo