Melting ice sheets, especially in Greenland, are changing the distribution of weight on Earth.
This has caused both the North Pole and the wobble, which is called polar motion.
If we lose mass from the Greenland ice sheet, we are essentially putting mass elsewhere.
And as we redistribute the mass, the spin axis tends to find a new direction.
The study was published Friday in the journalScience Advances.
The recent shift from the 20th-century direction is very dramatic, he added.
The motion has also sped up, though it still isnt very large.
Its no longer moving toward Hudson Bay, but instead toward the British Isles, said Adhikari.
Something east of Greenland has to be exercising an additional pull.
The researchers found the answer in Eurasia.
Ivins said he likes to think of it as a billion trucks each year dumping ice out of Greenland.
They all together pull polar motion towards the east, Adhikari said.
There is nothing to worry about, said Chen, who wasnt involved in the NASA study.
It is just another interesting effect of climate change.
source: www.techworm.net