Groundwater pumping has caused the Earth’s tilt to change by 80 cm over 17 years, scientists report in a study published in Geophysical Research Letters. Moving such a large mass of water has the greatest impact on shifting the Earth’s axis of rotation, among other climate-related factors.
Scientists discovered the impact of water on the Earth’s axis of rotation back in 2016, but until now they had not studied the contribution of groundwater to these changes. In the new study, the research team created a computer model that took into account observed changes in the tilt of the Earth’s axis of rotation and the movement of water. At first, the simulation included only ice sheets and glaciers, and then also various groundwater redistribution scenarios.
The resulting picture became consistent with observed changes in the Earth’s axis only after the researchers included displaced groundwater. Without them, the model deviated from real changes by 78.5 cm.
The Earth’s axis of rotation usually shifts by about a few meters during the year, the authors of the paper noted. Therefore, changes due to groundwater pumping do not carry a global risk, for example, the change of seasons. But on the scale of geological time, changes in the tilt of the planet can affect the climate.
Changes in the inclination of the planet can affect the climate
A change in the Earth’s tilt could affect climate on the geologic time scale, scientists warn. They point out that changing the tilt of the planet could change the distribution of solar energy, which, in turn, could affect climate conditions on Earth.
“Our study shows that the redistribution of groundwater has the greatest impact on the shift in the Earth’s axis of rotation,” says Ki Won-seo, lead author of the paper and a geophysicist at Seoul National University.
The scientists point out that groundwater pumping can lead to changes in the hydrological cycle, which can affect climatic conditions on Earth. They point out that this could lead to an increase in arid regions and a decrease in humid regions.
“Groundwater pumping could lead to changes in the hydrologic cycle and affect climate conditions on Earth,” said Jeffery Cavitt, professor of hydrology at Colorado State University.
Need to control groundwater use
Scientists warn that groundwater use needs to be controlled to avoid negative effects on the climate and ecosystem. They note that this can be accomplished by improving water use technology and water management.
“We need to control groundwater use to avoid negative effects on the climate and the ecosystem,” says Jeffery Cavitt.