The axis of rotation of the Earth is not fixed. This is manifested by a shift in the position of the poles. A movement followed for some time now by scientists. Today, they emphasize that anthropogenic global warming and more broadly, human activities, have significantly accelerated this natural movement.
The inclination of the axis of rotation of the Earth with respect to the plane of the ecliptic is not constant. Scientists are still trying to understand what exactly are the phenomena behind this variation. But the way water is distributed on the surface of our planet seems to be an important factor. And today, researchers at the Chinese Academy of Sciences tell us that the melting of glaciers due to the ongoing anthropogenic global warming has redistributed the water sufficiently to accelerate the displacement of the North Pole, causing it to swing from south to east. in the mid-1990s.
To reach this conclusion, the researchers calculated the total loss of water stored on land in the 1990s. They relied on data from melting glaciers and estimates of groundwater pumping. And the loss of water from the polar regions is the main driver of the polar drift. A drift whose average speed between 1995 and 2020 is approximately 17 times greater than that of the period 1981-1995.
The amazing impact of human activities on Earth
The increasingly rapid melting of the ice with global warming, however, cannot explain all of the drift. Although the researchers did not take their analysis that far, they believe that the remaining gap could result from disturbances in non-polar regions. Due, in particular, to the unsustainable pumping of groundwater for agriculture.
Results which show, according to the researchers, to what extent human activities can have an impact on our Earth. Going so far as to move its axis of rotation. Despite everything, without any real effect on our daily life. Since the operation could not, at most, change the length of our days by only a few milliseconds.
Our planet is not quite spherical. And its axis of rotation – which connects the North Pole to the South Pole through the center of the Earth – tends to oscillate and drift little by little. The 10 centimeters per year drift, that is to say some 10 meters in the single XX th century. Of researchers from NASA (USA) wanted to study the phenomenon. Using observational data and powerful models, they identified three processes that could explain it.
The glacial rebound, already incriminated by previous studies, is the best known of them. Glaciers tend to sink the surface of the Earth (much like when a person settles on a mattress ). When the ice melts , it gradually rises. But, according to NASA researchers, this phenomenon could not explain more than a third of the rotational drifts observed.
Natural causes and an anthropogenic cause
The convection of the Earth’s mantle is also involved for a third. Thus, under the effect of the heat emitted by the core of the Earth , rocks undergo a vertical circulation pattern. What to redistribute the masses and disrupt the rotation of our planet.
The last process involved is attributable to Man. It is indeed the melting ice of Greenland resulting from global warming . No less than 7,500 gigatons would in fact have been transferred to the oceans, responsible for a rise in sea level … and a drift in the axis of rotation of our planet.