Researchers from the University of California, specializing in American geology, report a surprising consequence of melting ice in Greenland and Antarctica: it can nudge the Earth’s spin. As warming releases massive amounts of freshwater into the oceans, the distribution of mass changes, subtly altering the planet’s angular velocity. The work was published in Nature, a leading scientific journal that compiles results from diverse fields to illuminate how natural systems respond to climate change. [Citation: Nature study, 2025 update]
The idea that the Earth’s rotation isn’t perfectly constant dates back centuries. Before precise timekeeping existed, only the timing of eclipses and other celestial events offered clues to rotation, and these signals traveled through a history of human observations. With modern instrumentation, scientists can detect minute variations in the planet’s rotation rate, turning what were once considered curiosities into measurable phenomena. This shift helps researchers understand how the planet’s interior and exterior systems interact and respond to external forces. [Citation: Chronology of rotation studies]
At the heart of the observation is the link between the planet’s inner core, mantle, and the overlying oceans. On average, the Earth’s rotation slows by about six millionths of a second every year due to those internal exchanges. While this drift may seem negligible in daily life, it becomes meaningful for technologies that demand extreme timing precision. Atomic clocks, internet time servers, and global transaction networks rely on consistent time standards, making even tiny shifts scientifically relevant and operationally significant. [Citation: Atomic clock networks]
Current research shows that the loss of polar ice accelerates the slowdown beyond historical trends. The mechanism is straightforward: as ice melts at the poles, freshwater moves toward lower latitudes, redistributing mass and reconfiguring the planet’s moment of inertia. This redistribution can lengthen the length of a day ever so slightly and, over years, accumulate into measurable changes in timekeeping systems used worldwide. The consequences extend to fields that depend on exact timing, including online computing, financial markets, and navigation services, where nanoseconds can matter for synchronization and pricing. [Citation: Timekeeping and climate dynamics]
In the broader context, scientists note physical routes for these effects. For example, scientists have identified features in polar ice sheets, such as deep channels that carry meltwater away from the ice mass into surrounding oceans. In Greenland, channels with walls that can reach several hundred meters in height illustrate how large volumes of meltwater can leave the ice sheet and potentially influence ocean circulation patterns. These processes feed back into the climate system and the planet’s rotation, creating a loop where warming reshapes mass distribution, which in turn influences the rotation and timekeeping technologies that society depends on. [Citation: Greenland meltwater channels]