Earth does not always spin on an axis running through its poles. Instead, it wobbles irregularly over time, drifting toward North America throughout most of the 20th Century (green arrow). That direction has changed drastically due to changes in water mass on Earth.
Captions and image source: NASA/JPL-Caltech
Excerpts;
Ice melting has caused a drift in polar motion.
Around the year 2000, Earth’s spin axis took an abrupt turn toward the east and is now drifting almost twice as fast as before, at a rate of almost 7 inches (17 centimeters) a year. “It’s no longer moving toward Hudson Bay, but instead toward the British Isles,” Surendra Adhikari, a researcher at NASA’s Jet Propulsion Laboratory, said.
Scientists have suggested that the loss of mass from Greenland and Antarctica’s rapidly melting ice sheet could be causing the eastward shift of the spin axis.
Read Full Article, LiveScience
Study Solves Two Mysteries About Wobbling Earth, NASA (04-08-2016)
Around the year 2000, Earth’s spin axis took an abrupt turn toward the east and is now drifting almost twice as fast as before, at a rate of almost 7 inches (17 centimeters) a year. “It’s no longer moving toward Hudson Bay, but instead toward the British Isles,” said Adhikari. “That’s a massive swing.” Adhikari and Ivins set out to explain this unexpected change.
