Global Warming

Global warming changing Earth's wobble

Melting ice sheets - especially in Greenland - are changing the distribution of weight on Earth. And that has caused both the North Pole and the wobble, which is called polar motion, to change course, according to a study published Friday in the journal Science Advances.

Scientists and navigators have been accurately measuring the true pole and polar motion since 1899 and for almost the entire 20th century they migrated a bit toward Canada. But that has changed with this century and now it's moving toward England, said study lead author Surendra Adhikari at NASA's Jet Propulsion Lab.

While scientists say the shift is harmless, it is meaningful. it highlights how real and profoundly large an impact humans are having on the planet.

Since 2003, Greenland has lost on average more than 600 trillion pounds of ice a year and that affects the way the Earth wobbles in a manner similar to a figure skater lifting one leg while spinning. On top of that, West Antarctica loses 275 trillion pounds of ice and East Antarctica gains about 165 trillion pounds of ice yearly.

These factors all combine to pull polar motion toward the east, Adhikari said.