We Are Slowing Down the Planet

We Are Slowing Down the Planet By Mark Thompson - March 24, 2026 05:07 PM UTC | Planetary Science This is a cool fact to impress your friends. The length of a day on Earth changes constantly, nudged by the Moon's gravitational pull, shifting winds in the atmosphere, and slow churning movements deep within the planet. It always has. Day length is, in a sense, a living measurement and one that ebbs and flows with the rhythms of a restless, dynamic world. But something new is happening. A study just published in the Journal of Geophysical Research: Solid Earth by researchers at the University of Vienna and ETH Zurich has found that our days are currently getting longer at a rate unprecedented in the past 3.6 million years and the primary cause seems to be human driven climate change! Air pollution by brick factories. The sun can be seen in the background just above the factory chimney, partially covered by the chimney's smoke (Credit : Janak Bhatta) The mechanism proposed is simple. As global temperatures rise, polar ice sheets and mountain glaciers melt, pouring water into the oceans and raising sea levels. That water spreads outward from the poles toward the equator, redistributing mass across the planet. Think of a figure skater who pulls their arms in tight to spin faster. When they stretch their arms out, they slow down. Earth is currently stretching its arms. The result is a measurable slowing of Earth's rotation currently lengthening our day by 1.33 milliseconds per century. That sounds trivial but it isn't. What makes this finding remarkable is not just the number, but its context. To find out whether anything similar had happened in the past, the researchers turned to an unlikely archive, the fossilised shells of tiny single celled marine organisms called benthic foraminifera, which lived on the ocean floor millions of years ago. The chemical composition of their shells encodes records of ancient sea levels. From those sea levels, the team could mathematically...