A new study in Science (published around early October 2026) shows that analysis of ancient continental flooding patterns reveals multiple episodes of relatively rapid “true polar wander” (TPW) over the past 320 million years.

True polar wander occurs when the solid outer Earth (crust and mantle) reorients relative to the planet’s spin axis (while the core and climate belts stay more fixed to that axis). This happens as Earth redistributes mass (e.g., via tectonic or mantle processes) to keep its rotation stable. It is distinct from magnetic pole reversals or ordinary plate tectonics.

Today, TPW occurs at roughly 10 cm per year (partly linked to ice- sheet melting), faster than average plate motion, but its past speed and frequency have been debated due to conflicting paleomagnetic data.

Rapid TPW shifts the solid Earth relative to the equatorial bulge created by rotation. This produces a distinctive “quadrupolar” (beachball or four- leaf- clover) pattern of relative sea- level change: two opposing quarters of the globe experience flooding while the other two become more exposed. The water itself stays put; continents effectively move through the bulge. This signature is not produced by other common processes.

Lead author Mathew Domeier (University of Oslo’s Centre for Planetary Habitability) and colleagues examined continental flooding reconstructions at 10- million- year intervals over the last 320 million years, combined with statistical modeling. They identified multiple robust quadrupolar patterns consistent with rapid TPW (rates exceeding roughly 0.6° per million years, faster than most tectonic plates).

Four intervals show strong signals:

• Early Jurassic (~200- 190 million years ago)
• Late Jurassic- Early Cretaceous (~150- 140 million years ago; one of the strongest)
• Mid-Cretaceous (~100- 90 million years ago)
• Oligocene- Miocene (~30- 20 million years ago; more debated or weaker)

These broadly align with some earlier paleomagnetic and plate- motion suggestions of rapid TPW, especially in the Jurassic and Cretaceous (Age of Dinosaurs). The study finds little evidence for rapid TPW through most of the Cenozoic and does not support the idea that TPW was the main driver of Pangea’s rapid northward motion in the late Carboniferous- Permian.

The findings challenge views that TPW has been negligible or always slow on geological timescales. Over millions of years, even these “rapid” shifts can move continents across climate zones (with less relative motion between them), influence sea- level patterns, and potentially affect climate, the biosphere, and other Earth- system processes. Researchers emphasize treating TPW as an episodic control rather than a constant background effect.

In short, ancient sea- level maps act as an independent “fingerprint” confirming that Earth’s geographic poles have wandered more dynamically, and episodically, than some prior models assumed.

Quadrupolar sea level fluctuations reveal episodes of rapid polar wander

True polar wander (TPW), when the solid outer Earth (crust and mantle) shifts relative to the planet’s spin axis, is hard to detect reliably with standard paleomagnetic methods. Domeier et al. used an independent approach based on reconstructions of ancient sea level as a proxy.

They identified a robust quadrupolar (degree- 2, order- 1 spherical harmonic, $Y_{21}$) pattern of global sea- level fluctuations caused by relative changes in centrifugal potential during rapid TPW. This shows that couplings among Earth’s rotational dynamics, mantle processes, and surface environments can be highly episodic.

True polar wander (TPW) is occurring today at ~10 cm/year, faster than the average rate of differential plate motion. It has been unclear whether this rate is only transient and negligible on geological timescales or whether Earth has experienced protracted rapid TPW lasting millions of years. Paleomagnetic data have suggested fast TPW episodes, but the limitations of that record have prevented definitive conclusions.

Rapid TPW should produce predictable global sea- level fluctuations tied to changes in centrifugal potential. The authors tested this prediction using continental flooding reconstructions and found multiple robust quadrupolar patterns since 320 million years ago. This confirms that protracted rapid TPW has occurred on Earth.

Key findings (from the paper and supporting materials)

• Analysis of continental flooding maps at 10- Myr intervals, combined with statistical modeling, revealed significant $Y_{21}$ (quadrupolar and or tesseral) signals.
• Four main episodes with rates ≥ ~0.6° per million years (a conservative lower bound inferred from forward modeling of viscoelastic Earth responses):
  • ~200- 190 Ma (Early Jurassic)
  • ~150- 140 Ma (Late Jurassic- Early Cretaceous; one of the strongest)
  • ~100- 90 Ma (mid- Cretaceous)
  • ~30- 20 Ma (Oligocene- Miocene)
• These signals are robust even after tests for regional confounding effects.
• Little evidence for rapid TPW through most of the Cenozoic.
• No significant support for the hypothesis that rapid northward motion of Pangea in the late Carboniferous- Permian was driven primarily by TPW.
• The results broadly corroborate some earlier paleomagnetic and plate- motion studies while providing an independent test that avoids many of their limitations.

Implications

The work refutes the view that TPW has been negligible or persistently slow on geological timescales. It highlights TPW as an episodic control on sea- level change and, potentially, other global environmental and biological processes (e.g., by moving continents across climate belts while relative plate positions change less).

Data and codes are available on Zenodo (version linked in the supplementary materials). The full paper is behind the Science paywall; the abstract, editor’s summary, and supplementary materials (including methods details on the $Y_{21}$forward model and rate bounds) are the primary publicly extractable content. Secondary coverage in outlets such as New Scientist, Scientific American, and AAAS summaries expands on the environmental context.

Journal information: Science, Vol. 394, Issue 6819, pp. 87- 90 (1 October 2026)

DOI: 10.1126/science.aec8423

Authors: Mathew Domeier, Leandro C. Gallo, Chloé M. Marcilly and Trond H. Torsvik 

Abstract

True polar wander (TPW) is presently occurring at a rate of ~10 centimeters per year, exceeding the mean rate of differential plate motion. Whether this rate is transient and negligible on geological timescales or whether Earth has experienced rapid TPW lasting millions of years is unclear. Paleomagnetic evidence has been used to propose fast episodes of TPW, but limitations of the paleomagnetic record have precluded definitive results. Rapid TPW will induce global sea level fluctuations associated with relative changes in centrifugal potential, offering an independent test. We evaluated this prediction using continental flooding reconstructions and identified multiple robust quadrupolar patterns since 320 million years ago, confirming that protracted rapid TPW has occurred on Earth and that couplings among Earth’s rotational dynamics, mantle processes, and surface environments can be strongly episodic.