The Earth spins around its axis, and the rotation is what causes our 24-hour day. But what you probably didn’t know is that the Earth doesn’t have a smooth rotation. It’s a bit wobbly, and NASA scientists believe that the spin-axis drift known as “polar motion” might be a result of climate change.
Scientist previously believed that the single culprit for the polar motion was glacial rebound – a phenomenon, which usually happens when the surface of the Earth starts reclaiming the original shape after glacial coverage from the last ice age melts. However, scientists now have found two other processes that affect it.
NASA’s Jet Propulsion Laboratory published an article according to which mantle convection and climate change are also affecting polar motion.
Mantle convection is the material in the Earth’s mantle which circulates and is fueled by heat from the core of the planet.
A Concerning Climate Change Effect
The third cause seems to be climate change. Ice melting is a concern all over the planet, but the ice sheets in Greenland (that keep on melting) affect polar motion.
The paper was published in Earth and Planetary Science Letters, and titled “What drives 20th century polar motion?” NASA JPL’s Eric Ivins, one of the authors of the paper, explains their findings:
“There is a geometrical effect that if you have a mass that is 45 degrees from the North Pole — which Greenland is — or from the South Pole (like Patagonian glaciers), it will have a bigger impact on shifting Earth’s spin axis than a mass that is right near the Pole.”
The image shown above describes the three processes that affect polar motion. The ice loss in Greenland is depicted with a blue dotted line, the mantle convection with red, and the postglacial rebound with yellow.
This discovery will lead to future research and scientists will probably figure out how much climate change affect Earth’s wobble. Finally, as Greenland’s ice continues to melt, the intensity of polar motion will grow.
Andre Blair s is the lead editor for Advocator.ca. He holds a B.A. in Psychology from the University of Toronto, and a Master of Science in Public Health (M.S.P.H.) from the School of Public Health, Department of Health Administration, at the University of North Carolina at Chapel Hill. Andre specializes in environmental health, but writes on a variety of issues.