Exploring the role of Mantle and Paleomagnetic Reference Frames with Intermediate Complexity Climate Models

The distribution of continents and oceans through deep-time has shaped the Earth’s changing climate and geography in a way that is vital for understanding processes ranging from the evolution and migration of living organisms to the distribution of economic mineral deposits, and the precise contribution of anthropogenic CO₂ to the present climate. Despite this, producing climate models of an evolving Earth across long periods of geological time have been challenging due to the immense computational resources required, and as a result, deep-time paleo-climate models have tended to focus on single ages. Here we demonstrate the use of an intermediate-complexity atmosphere-ocean Plasim-Genie tool to produce a suite of models that illustrate the evolving climate with evolving continents over hundreds of millions of years.

Using this approach, we explore the impact of modelling paleoclimate with a pure paleomagnetic plate reference frame versus a plate motion model that uses a mantle reference frame. These two plate reference frames may have latitudinal differences of up to 15 degrees even in the well-constrained timeframe of the last 100 Myr. We demonstrate with Plasim-Genie that these latitudinal differences result in significant discrepancies in climate in a range of key regions. Users of paleoclimate model data, particularly those studying biology and geography of the past should be aware of the plate reference frame used in generating the climate data. As the Earth’s magnetic field averages to align with the Earth’s spin axis, we suggest that a paleomagnetic reference frame is the preferred reference frame to use for paleoclimate modelling.