Climate change is physically changing the Earth’s rotation on its axis, NASA scientists have discovered. New research, published in Science Advances, shows that an observed directional change in the planet’s wobble can be attributed to mass redistributions that result from melting ice in Greenland and Antarctica.
It’s worth noting that it’s nothing new for the Earth’s poles to shift around a little bit. Humans have been keeping records of polar shifts since 1899 and, in that time, the North Pole has consistently moved in the direction of Canada. But over the last two decades the vector has changed. Now the pole is slowly creeping towards England.
“The recent shift from the 20th-century direction is very dramatic,” lead author Surendra Adhikari with NASA’s Jet Propulsion Lab told Phys.org.
In order to account for this observed change, the study authors calculated climate-driven mass redistribution on the planet from 2003-2015, and how they would theoretically impact the polar wobble. And indeed, their reconstruction very closely predicted the change in direction of the polar wander.
Earth’s rotation is a function of the distribution of mass on the planet, so it makes sense that uneven melting would shake things up a bit. Greenland is dumping 600 trillion pounds of ice into the oceans each year. The balance is shifting in Antarctica, too — the western half of the continent is losing billions of tons of ice annually, and the eastern half gains nearly as much. These processes compound each other to move mass away from the west, which pushes the North Pole to the east.
The scientists who study this say the changing wobble is harmless. “There is nothing to worry about,” said Jianli Chen with University of Texas’ Center for Space Research, who authored an earlier study that pointed to climate change as a cause of polar wobble. “It is just another interesting effect of climate change.”
Even if the planet is not going to suddenly tip over on its axis as a result of this, the finding is highly unnerving. It highlights just how fundamentally humans are changing the physical and geological history of this planet. Other ways the planet reacts to a warming atmosphere — weaker jet streams and collapsing ice sheets, for example — are far less benign.