The Earth’s axis is not static but is always moving. The way water is distributed on Earth’s surface is one factor responsible for the shift.
Researchers have been able to determine the causes of polar drifts starting from 2002 based on data from the Gravity Recovery and Climate Experiment (GRACE). The mission gathered information on how mass is distributed by measuring changes in gravity at different points.
Research has determined more recent movements of the North Pole to be caused by factors like molten iron in the Earth’s outer core. Other shifts are caused by the process where frozen water in glaciers and groundwater stored under our continents is being lost through melting and groundwater pumping.
Using data on glacier loss and estimations of groundwater pumping, Suxia Liu, a hydrologist at the institute of Geographic Sciences and Natural Resources Research, and her colleagues calculated how the water stored on land changed. They found that the contributions of water loss from the polar regions is the main driver of polar drift.
The faster ice melting couldn’t entirely explain the shift, said Shanshan Deng, one of Liu’s colleagues. While they didn’t analyze this specifically, she postulated that the slight gap might be due to activities involving land water storage in non-polar regions, such as unsustainable groundwater pumping for agriculture.
https://phys.org/news/2021-04-climate-shifted-axis-earth.html