A Method for Habitability Analysis of Planets with True Polar Wander

Abstract Finding unambiguous signs of extraterrestrial life is a central challenge in astrophysics and astrobiology. Habitability assessments typically focus on conditions such as the presence of liquid water. However, True Polar Wander (TPW)—the motion of the planet’s rotation axis relative to its surface—can produce large latitudinally dependent climate perturbations that are not captured by typical energy balance models. Here, we present a theoretical framework that incorporates TPW into a planet’s global energy balance model. The framework couples the radiative balance with the geometric and temporal effects of pole reorientation and identifies the planetary structural and atmospheric prerequisites for significant climate forcing induced by TPW: an atmosphere that allows for surface, grounded ice formation and ablation, and an interior that supports viscous mantle flow (sufficient mantle viscosity and convective vigor) so that TPW can occur on geologically relevant timescales. Using analytic arguments, we show that both the amplitude and the direction of TPW modify latitudinal insolation and surface albedo in ways that can drive abrupt, global redistribution of ice and surface temperatures. Above certain thresholds of TPW, these changes can produce rapid climate transitions with major implications for biospheric stability, as has been reported for the case of the planet Earth. Although the link between TPW and specific extinction events on Earth remains debated, TPW is a plausible mechanism for large, rapid environmental change on habitable worlds. Our methodology is broadly applicable to planets that undergo TPW and yields testable predictions that might help prioritize observational targets in the search for life.