Liquid iron in Earth's outer core, located approximately 2200 kilometers beneath the surface, has suddenly altered its movement. Beneath the Pacific Ocean, a large stream of molten material shifted in 2010 from a weak westward flow to a strong eastward one.
Scientists are still unable to explain what triggered this reversal. Data from European Space Agency satellites, including the Swarm and CryoSat missions, along with earlier observations from CHAMP and Ørsted, have enabled a detailed tracking of the event.
A study published in the Journal of Studies of Earth's Deep Interior indicates that such large-scale changes in core circulation can occur much faster than previously believed. It was formerly thought that large-scale flows remained relatively stable over decades.
The study's lead author, Frederik Dahl Madsen from the University of Edinburgh, notes: “The large-scale flow reversal beneath the Pacific Ocean raises new questions about the behavior of Earth's deep layers.” He adds that the strong eastward flow began to weaken around 2020.
Researchers suggest a possible link between this reversal and changes within the inner core, which are detected through geodetic and seismological data. What, then, lies behind these profound alterations?
While changes in the core pose no direct threat to humans or the climate, they directly impact the planet's magnetic field. This field protects Earth from solar radiation and is crucial for navigation and satellite operations.
Anja Strømme, Swarm mission manager, emphasizes the value of long-term satellite measurements, noting that they allow for real-time tracking of the geodynamo's evolution. Scientists plan to continue monitoring to determine whether the reversal is a short-term fluctuation, part of a cycle, or a new stable state.
According to mission scientist Elisabetta Iorfida, regional changes can emerge in just a decade. This opens new avenues for studying the interaction between the outer core, inner core, and lower mantle.
