Earth Has "Spare Tire"—And Ice Melt's Keeping It That Way
Waistline bulge has stopped slimming, thanks to massive melting.
(Related: "Antarctica Ice Loss Faster Than Ten Years Ago" .)
Researchers have long known that Earth isn't a perfect sphere. Rotational forces cause the planet to bulge at its waistline. A person standing at the North Pole, for example, is about 13 miles (21 kilometers) closer to the center of Earth than someone at the Equator.
That difference has been shrinking, at least over the long term. Ever since scientists have been measuring the equatorial bulge, it's been retracting at a rate of seven millimeters (about a quarter of an inch) a decade—part of a long rebounding from the Ice Age, which lasted from about 2.6 million to 11,700 years ago.
During the Ice Age, "all that ice is sitting there, and