How Melting Ice Has Altered Time-Keeping
Climate change is transforming our measurements of many things—summer temperatures, the level of the seas, the strength of hurricanes, for instance. But now, as polar ice caps melt with more regularity, it’s even messing with how we keep time.
According to a recent paper in Nature, that polar thaw has progressed to such an extent that it’s slowing the rotation of the planet. As the melt runs into the ocean, the extra water gathers around the Earth’s belly, fattening it a bit around the equator and reducing the planet’s angular velocity—or rate of spin. Think of an ice skater slowing her axel by extending her arms and you get the picture.
A slower rate of spin, in turn, alters the time it takes for the planet to rotate once—what we think of as a day—which means the rising and
