Something ‘unprecedented’ is now happening to Earth’s rotation, scientists say

Key Points:

• Earth’s rotation is slowing at an unprecedented rate in the last 3.6 million years, primarily due to climate change-induced melting of polar ice sheets and glaciers, which redistributes mass from the poles toward the equator.
• This mass shift causes a measurable lengthening of the day by about 1.33 milliseconds per century, an effect comparable in energy to a magnitude 9.0 earthquake and involving the movement of approximately 1,000 gigatonnes of ice.
• Researchers used fossilized benthic foraminifera shells and machine learning algorithms to analyze geological data dating back to the Late Pliocene, confirming that current changes exceed natural variations except for one rare event two million years ago.
• If high emissions continue, climate change is projected to become the dominant factor affecting Earth’s rotation by 2100, surpassing even the Moon’s gravitational influence, with implications for precise technologies like GPS and spacecraft navigation.
• The study highlights the profound impact of human activity on Earth’s physical systems, with ongoing research focusing on additional effects such as groundwater depletion and water cycle changes to better understand their influence on planetary rotation.