Melting ice and human-caused factors are impacting changes in the Earth's axis

A shift in the normal movement of the poles that occurred in the 1990s was likely the result of in increase in glacial melting, according to a new study from the American Geophysical Union (AGU).

The exact locations of the North and South poles are not static and are constantly moving. One factor that can influence these polar shifts is the way water is redistributed on the Earth's surface.

This July 17, 2011, photo shows the melting front of a glacier at the edge of the Greenland ice sheet, near Kangerlussuaq, Greenland. Greenland is the focus of many researchers trying to determine how much its melting ice may raise sea levels. (AP Photo/Brennan Linsley)

AP Photo

Accord to the AGU report, the melting of glaciers during the mid-1990s caused enough redistribution of water to influence the drift of the poles by causing them to turn and accelerate eastward.

Key excerpts from the AGU report.....

The Earth spins around an axis kind of like a top, explains Vincent Humphrey, a climate scientist at the University of Zurich who was not involved in this research. If the weight of a top is moved around, the spinning top would start to lean and wobble as its rotational axis changes. The same thing happens to the Earth as weight is shifted from one area to the other.

The study determined that the average speed of polar drift from 1995-2020 increased about 17 times from the average speed recorded from 1981-1995.

“I think it brings an interesting piece of evidence to this question,” said Humphrey. “It tells you how strong this mass change is—it’s so big that it can change the axis of the Earth.”

The faster ice melting couldn’t entirely explain the shift, said Shanshan Deng, a researcher at the Institute of Geographic Sciences and Natural Resources Research at the Chinese Academy of Sciences, the University of the Chinese Academy of Sciences and an author of the new study. While they didn’t analyze this specifically, she speculated that the slight gap might be due to activities involving land water storage in non-polar regions, such as unsustainable groundwater pumping for agriculture.

This change in the Earth's axis is not enough to change daily life on the planet, but it would change the length of day by milliseconds, according to the report.