Since the 1990s there has been a change in the movement of the poles, something that, according to the latest study published in the journal Geophysical Research Letters , is due to the melting of glaciers due to global warming.
The Earth rotates around an axis, like a spinning top
The locations of the north and south poles are not static and immutable places on our planet . The axis around which the Earth rotates, or more specifically the surface from which the invisible line that connects the north and south geographic poles of the planet emerges, is always moving due to processes that scientists do not fully understand. And this is exactly what has happened in the last three decades as a result of global warming, which has melted hundreds of billions of tons of ice from the poles, especially the north pole.
According to scientists, since 1980, the position of the two poles has shifted by about 4 meters. Doesn’t that sound like a lot? Although this modification does not affect our lives or the normal course of nature, on a global level it is another testimony of the power that humanity is having over planet Earth. Our impact is so profound that we have even been changing without realizing the very axis on which the Earth rotates.
The researchers examined the phenomenon of polar wandering, in which the Earth’s north and south magnetic poles drift around the planet’s surface which, although known to be driven by many factors, other elements also contribute, such as the effects anthropogenic (man-made) climate change.
“The faster melting of the ice under global warming was the most likely cause of the reversal of polar drift in the 1990s, ” explains lead researcher Shanshan Deng of the Institute of Geographical Sciences and Natural Resources Research in China.
They found that the contributions of water loss from the polar regions were the main driver of polar drift, added to the water loss from the non-polar regions. Taken together, all of this lowering of water accounted for the eastward shift in polar drift. Thus, the average speed of polar drift has accelerated in recent years: the drift from 1995 to 2020 was 17 times faster than that from 1981 to 1995 . This period also coincides with massive melts in the Arctic and Antarctica.
But it’s not just melting that drives polar drift
The study showed that glacier losses accounted for most of the change, but groundwater pumping likely contributed to the movements as well. Groundwater is stored underground, but once it is pumped for drinking or agriculture, most of it ends up flowing into the sea, redistributing its weight around the world . All this mass that used to be stored and concentrated in certain places has now spread throughout the world’s oceans and seas. To put us in context, in the last 50 years, humanity has extracted 18 trillion tons of water from deep underground reservoirs without it being replaced.
Experts say this evidence reveals how direct human activity can impact changes in the body of water on earth. Their analysis revealed large changes in the water body in areas like California, North Texas, the region around Beijing, and North India, for example, all areas that have been pumping large amounts of groundwater for agricultural use. . Both the depletion of groundwater and the melting of polar glaciers are due to unsustainable human activity.
What ramifications will this have for us in the future? We’ll have to wait and see.
Referencia: S. Deng et al, Polar Drift in the 1990s Explained by Terrestrial Water Storage Changes, Geophysical Research Letters (2021). DOI: 10.1029/2020GL092114
