Researchers Claim to Know Why the Earth’s Rotation Is Wobblier Than Before
Environmental change has caused many alterations to the planet Earth. One of its impacts was explained in detail in a study published in Science. This impact has been felt for a long time in one of the movements exhibited by the planet, stated IFL Science.
For a long time, experts have been observing a change in the planet's rotation. Earth has become more unsteady or wobbly because of a shift in its axis. The axis had reportedly shifted by 45 cm from its normal position. This change has been deemed so important because it impacts pursuits like tracking, according to Science Focus.
"You might wonder why a small shift like this is interesting or even worth measuring," said co-author Professor Clark Wilson of the University of Texas at Austin. "I always like to point out that every GPS position you get on your phone depends on knowing where the pole is. So the motion of the pole is very carefully monitored – down to the millimetre."
Several reasons were cited for this change, from loss of ice, changes in the core, to glacial rebound, over the years by experts. A new study has now determined the exact cause, and it is none of these. Their calculations suggest that a massive loss of soil moisture that has happened on the planet in recent decades has caused this alteration.
The study claimed that a climate model had previously suggested that from 2000 to 2002, Earth's soil lost around 1,600 gigatonnes of water. This huge amount of water was then drained into the oceans. The whole phenomenon reportedly left an impact on the planet's balance. Researchers believe that this redistribution of mass from one area to another had an impact on Earth’s moment of inertia. This effect eventually started shifting the planet's axis.
According to experts, the whole system is like a spinning top. Any change in mass will shift the axis on which the top is spinning. Scientists were aware of this theory, but believed that only factors like a change in landform due to glacier melting or loss of the Antarctic and Greenland ice sheets could facilitate the shift. However, the study, with its calculations, asserts that the soil moisture loss in recent decades has been massive enough to cause the shift.
To verify whether this loss actually happened, the team analyzed satellite radar data as well as some models of soil moisture. The results indicated that there was indeed a drop in soil moisture in these years. Along with this drop, there was also an elevation of 1.95mm in global mean sea level every year. The team used the same methods for an expansive range, which included the late 20th and early 21st century. The results indicated that between 2003 to 2016, 1,000 gigatonnes of water were lost from the soil. Examinations further showcased that even by 2021, the moisture had not recovered. This implied that the planet's land water had indeed undergone a major change.
Though experts are not entirely sure about the reasons behind the moisture loss, the study puts forward some speculations. These speculations include lower-than-average rainfalls in the early 21st century, as well as increasing demand for atmospheric moisture. The soil moisture loss phenomenon had largely gone unnoticed in popular imagination. This study showcases that even a change in environment that did not immediately produce consequences could impact the planet significantly over decades.