Water is one of the essential elements of our planet and its distribution influences the rotation of the earth. By pumping and redistributing vast amounts of groundwater, humans altered the Earth’s axis of rotation, causing the geographic north pole to shift east by nearly 80 centimeters between 1993 and 2010, according to a study published in the journal Geophysical Research Letters . Image illustration Pixabay
Ki-Weon Seo, a geophysicist at Seoul National University and leader of the study, says that “among the climate-related causes, groundwater redistribution actually has the greatest impact on the axis of rotation.”
Water’s ability to alter the Earth’s rotation was discovered in 2016. So far, the specific contribution of groundwater to these changes has not been explored. In the new study, the researchers modeled the observed changes in Earth’s north pole drift and water movement, first considering only ice caps and glaciers and then adding different scenarios for groundwater redistribution.
The observed shift of the Geographic North Pole (red arrow, “OBS”) compared to model results without (dashed blue arrow) and with (solid blue arrow) groundwater mass redistribution. The groundwater mass redistribution model fits the observed shift much better and tells the researchers the extent of the groundwater influence on the Earth’s rotation.
Credits: Geophysical Research Letters
The model only fitted the observed polar drift when the researchers accounted for 2,150 gigatonnes of groundwater redistribution. Without this deviation, the model was 78.5 centimeters outside the observation, which corresponds to a drift of 4.3 centimeters per year.
The location of the groundwater has a different influence on the rotation axis of the earth. Thus, mid-latitude water has a greater influence. During the study period, water was redistributed primarily in North America and northwestern India.