Wobbles in the planet’s rotation are due to various influences, including the distribution of mass.
Observations conducted since 1899 have shown that the North Pole has been drifting south toward eastern parts of Canada at the rate of about 4 inches per year.
But that drift jogged abruptly eastward in 2005 and has totaled about 4 feet in distance since then.
Jianli Chen of the University of Texas at Austin and colleagues collected data from NASA’s GRACE satellite, which measures changes in Earth’s gravity field over time in an attempt to find out why the shift occurred.
The measurements allowed them to calculate how melting of the Greenland and Arctic ice sheets and mountain glaciers, and the resulting rise in sea level, caused a redistribution of mass on the Earth’s surface.
Computer analysis determined that it matched perfectly what it would take to cause the observed shift in the North Pole’s position.
“Ice melting and sea level change can explain 90 per cent of the (eastward shift),” Chen told the fall meeting of the American Geophysical Union in San Francisco. “The driving force for the sudden change is climate change.”
His team determined that the largest contributing factor of the shift is the melting of the Greenland ice sheet, which is losing about 250 gigatons of ice each year.