Modelling the Phanerozoic: Discrepancies and conformity with the geological record

The Phanerozoic Eon is characterized by profound variability in global climate and biogeochemical cycles, driven by some combination of the formation and break up of supercontinents, changes to tectonic degassing, the emplacement of Large Igneous Provinces and by biosphere evolution. Understanding the key drivers of these environmental transitions is an ongoing challenge in deep-time Earth system science.

The Spatially Continuous IntegratiON (SCION) climate-biogeochemical model is often used for the analysis these processes, and has successfully reproduced a number of first-order global trends through the Phanerozoic (1) and Neoproterozoic (2), including reconstructions of atmospheric CO₂, atmospheric O₂, and surface temperature. But many notable mismatches still occur, e.g. during the late Paleozoic icehouse interval and in the underestimation of warmth during the Cretaceous greenhouse period. Furthermore, many novel or revised proxy records have not yet been compared to the model outputs (e.g. global erosion rates (3), or new records for Phanerozoic temperature evolution (4) and atmospheric CO₂ (5)).

Here, we present a new integration of multiple environmental proxy record compilations with the SCION model outputs. We determine the key periods of model-data mismatch and explore possible solutions within the current model formulation, or possible model extensions. We then suggest critical intervals where proxy development or sampling work may be best directed.

 

(1) Merdith et al., 2025, Science Advances

(2) Mills et al., 2025, Global and Planetary Change

(3) Hay et al., 2006, Palaeo3

(4) Judd et al., 2024, Paleoclimate

(5) Steinthorsdottir et al., 2024, Treatise on Geochemistry