Overview
- A Science paper published this week reports independent evidence that the solid Earth has tipped relative to its spin axis in at least four rapid episodes across the past 320 million years.
- The team led by Mathew Domeier used continental flooding reconstructions sampled at 10‑million‑year intervals to detect a characteristic quadrupolar inundation pattern that signals true polar wander.
- The study identifies strong TPW signals in the Early Jurassic (200–190 Ma), Late Jurassic–Early Cretaceous (150–140 Ma), mid‑Cretaceous (100–90 Ma) and Oligocene–Miocene (30–20 Ma).
- Modern satellite geodesy shows much smaller present‑day motion of about 10 centimeters per year tied mainly to ice‑mass loss, which the authors say confirms TPW is active today but driven by different short‑term processes.
- Key questions remain about what triggers rapid TPW and how far the globe reorients; the authors warn that episodic TPW could have altered past coastlines, shifted climate zones, affected ecosystems and may interact with Earth’s magnetic field, so cross‑disciplinary work is needed to pin down causes and impacts.