Climate change is causing a “lateral overload” on the Earth’s axis of rotation. That is stated in a new study published in Earth and Planetary Science Letters, which determines that the axis is not stable anymore due to the melting of the ice of Greenland which equivalates with 7,500 gigatons of water that ended up in oceans.
The study, developed by NASA’s Jet Propulsion Laboratory, estimates that the Earth’s axis has shifted about ten centimeters throughout the 20th century, and that would continue if we take no measures to tackle global warming, as explained by the study’s leading author, Surendra Adhikari.
Here’s how climate change is affecting the Earth’s axis
In an article published on the NASA website, JPL researcher and co-author of the study, Erik Ivins, explains how this situation occurred.
“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,” Erik Ivins said.
Therefore, climate change is affecting the stability of the Earth’s axis, causing it to “wobble,” as researchers say. “Earth is not a perfect sphere. When it rotates on its spin axis — an imaginary line that passes through the North and South Poles — it drifts and wobbles. These spin-axis movements are scientifically referred to as ‘polar motion.'” the NASA’s JPL article reads.
The three phenomena that cause the Earth’s axis to wobble
The researchers explain that the redistribution of the Earth’s mass, changes on the surface, ice sheets, oceans and the flow of the mantle all affect the rotation of the planet. Among the various factors, experts highlight the increase in temperatures throughout the 20th century, which led to a decrease in Greenland’s ice mass. That process has led to a rise in sea level and, consequently, to a drift in the Earth’s axis of rotation.
To date, various studies have pointed to glacial rebound as the vital factor in polar movement. During the last ice age, massive glaciers depressed the planet’s surface. However, when these glaciers moved or melted, the Earth slowly returned to its original position, causing a change in the axis of rotation. However, scientists say the glacial rebound is responsible for only one-third of the polar drift.
On the other hand, the researchers explain that the convention of the mantle (which is responsible for the movement of the tectonic plates) is also responsible for the polar drift.