A schematic showing the atmospheric sources and sinks that define the new volatile cycling processes in VPLanet’s ThermInt module, inspired by Figure 1 in B. J. Foley (2015). Fluxes related to CO₂ are color-coded magenta, and fluxes related to H₂O are color-coded teal. We incorporate the climate-stabilizing carbon cycle from B. J. Foley (2015), tracking the mass of CO₂ across the mantle (c_man), plate (c_plate), and surface (c_surf) reservoirs. We include the deep water cycle from J. Seales & A. Lenardic (2020), and a precipitation/evaporation parameterization from P. Driscoll & D. Bercovici (2013), which allow us to track the mass of H₂O across the mantle (w_man) and surface (w_surf) reservoirs. At each time step, surface carbon and water are partitioned into the atmosphere (c_atm, w_atm) and the ocean (c_ocean, w_ocean) by enforcing equilibrium at the air–water boundary. This schematic does not depict the modeled ocean chemistry.