Human pumping of groundwater is capable of significantly shifting the axis of rotation of the Earth. This conclusion was made by South Korean scientists in an article published in Geophysical Research Letters.
In 2016, scientists showed that the natural redistribution of water and ice on the planet affects its rotation. However, until recently it was unclear what role the redistribution of water caused by human economic activity, and in the first place, the pumping of groundwater, plays in it.
In a new study, scientists from Seoul National University attempted to answer this question by simulating the observed drift of Earth’s axis of rotation and the movement of water masses on the planet. They first took into account only the movement of ice on land and on the ocean, then added a scenario with the movement of groundwater. Based on climate models, scientists previously calculated that between 1993 and 2010, humanity pumped 2,150 gigatonnes of groundwater, equivalent to a six millimeter rise in ocean levels.
Seo et al. (2023), Geophysical Research Letters
A modeling that only takes into account the movement of the ice did not reveal any correspondence with the observed drift of the axis of rotation of the planet. The simulated drift only matched the real one when 2150 gigatons of water pumped out of the ground was added to the model.
Extracting groundwater can move the Earth’s axis of rotation, much like a small weight can change the motion of a spinning top. “The Earth’s axis of rotation shifts a lot,” said study author Ki Won Seo. “Our study showed that of all climate-related causes, groundwater redistribution actually has the greatest impact on axis drift.”
Calculations showed that due to the pumping of groundwater by man during the specified period, the axis of rotation of the Earth shifted 78.5 centimeters to 64.16 ° east longitude, or 4.3 centimeters per year. According to scientists, the distribution of groundwater on the planet depends on how their pumping affects the drift of the axis of rotation. For example, during the period studied, the greatest amount of groundwater was redistributed mainly to the west of the North American continent and to the northwest of India.
Due to natural causes, the axis of rotation drifts a few meters each year, so changes associated with human water use cannot affect the changing seasons. However, on the scale of geologic epochs, pole shift can impact climate change, said Surendra Adhikari of NASA’s Jet Propulsion Laboratory.
From now on, scientists intend to turn to a more distant past. “Observation of the Earth’s axis of rotation is useful for understanding variations in water content across continents. Data on the movement of the axis of rotation have been available since the end of the 19th century. Therefore, we can use them to estimate the evolution of inland water reserves over the last hundred years. Have there been changes in the hydrological regime due to warming? The answer may come from the movement of the poles,” added the author.
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