Climate change may have changed the direction of the North Pole drift
A new study suggests that the sudden turn of the North Pole in the 1990s was probably due mainly to the melting of glaciers associated with climate change.
The location of Earth’s geographic poles, where the planet’s axis pierces the surface, are not fixed. They wander in seasonal and near-annual cycles, primarily driven by weather patterns and ocean currents. But in addition to moving relatively dense swirls only a few meters across, the poles drift over time as the planet’s weight distribution shifts and changes its rotation along its axis.
By the mid-1990s, the North Pole had shifted toward the western edge of Ellesmere Island, Canada. But then the pole turned eastward about 71 degrees toward the northeastern tip of Greenland. It continues to move in the same direction, moving at about 10 centimeters a year. Scientists don’t quite understand why the shift occurred, said Suxia Liu, a hydrologist at the Institute of Geographic Sciences and Natural Resources Research in Beijing.
Liu and his colleagues looked at how well the polar drift trends matched previous studies of glacial melting around the world. In particular, glacial melting in Alaska, Greenland, and the southern Andes accelerated in the 1990s. The timing of this melting, as well as the effect it would have on the Earth’s mass distribution, suggests that the melting of glaciers caused by climate change helped cause a change in polar drift, the team reports in its April 16 letters on geophysical research.
The team’s analysis shows that while melting glaciers can explain much of the change in polar drift, it doesn’t explain it all. So there are probably other factors involved. For example, with abundant irrigation, groundwater pumped from aquifers in one region may end up in a distant ocean. The team reports that, like melting, water management alone cannot explain the direction of the North Pole, but it can push the Earth’s axis significantly.
“The results show how much human activity can affect changes in the mass of water stored on land,” says Vincent Humphrey, a climate scientist at the University of Zurich who was not involved in the study. – And they show how significant these mass shifts can be – so much so that they can change the Earth’s axis.”Tags: climate, North Pole