Calculating potential cumulative carbon fixed and evolutionary stage for Earthlike planets in our solar neighborhood

We propose a novel method for estimating possible evolutionary stage on exoplanets based on the hypothesis that evolutionary rate is a linear function of cumulative carbon fixed on an entire planet.  We explore the implications of this hypothesis using spatially explicit climate simulations of TRAPPIST-1e, a tidally locked planet within the habitable zone of a red dwarf star ~40 light years away.  We estimate that Earth has cumulatively fixed ~9.4 e25 g C carbon, and TRAPPIST 1e (T1e) as an ocean world with 400 ppm CO2 using photon energy of wavelengths 400 -1100 nm would need 22 Gy years to fix the same amount of carbon.  Since T1e's mean estimated age is 7.6 Gyr, we estimate it to be at a potential microbial, but not multicellular life stage.  We then apply this technique to 29 nearby exoplanets that may have the conditions suitable for harboring life and using 400-1100nm light, assuming a 30% continent ratio. We identify one planet that surpasses Earth’s cumulativ..., 2.1 T1e climate and NPP
We used simulated climatology data for T1e from the THAI experiment (Fauchez et al., 2021, 2020) as well as GCM simulated modern Earth climatology to estimate surface productivity for different atmosphere and surface composition scenarios.  For most results, we used the Met Office Unified Model (UM) model (Mayne et al., 2014) simulations (144 by 90 pixels) of the downwelling shortwave (SW) solar flux at surface (FSWdown), time-average precipitation flux and surface temperature (TS) (downloaded from https://thai.emac.gsfc.nasa.gov/organization/thai on June 1, 2024).  We also compared these results to simulations from ExoCAM (Exoplanet Community Atmosphere Model - derived from the CAM4 NCAR model).   For most results, we used Hab 1 simulations of a single layer slab ocean covered planet with 400 ppm CO2, but we also employed Hab 2 simulations which have an atmosphere of 1 bar of CO2 averaged over between 10 and 100 orbits.  We used two mode..., , # Calculating potential cumulative carbon fixed and evolutionary stage for Earthlike planets in our solar neighborhood

[https://doi.org/10.5061/dryad.37pvmcvvk](https://doi.org/10.5061/dryad.37pvmcvvk)

## Description of the data and file structure

We used simulated climatology data for T1e from the THAI experiment (Fauchez et al., 2021, 2020) as well as GCM simulated modern Earth climatology to estimate surface productivity for different atmosphere and surface composition scenarios.  For most results, we used the Met Office Unified Model (UM) model (Mayne et al., 2014) simulations (144 by 90 pixels) of the downwelling shortwave (SW) solar flux at surface (FSWdown), time-average precipitation flux and surface temperature (TS) (downloaded from [https://thai.emac.gsfc.nasa.gov/organization/thai](https://thai.emac.gsfc.nasa.gov/organization/thai) on June 1, 2024).  We also compared these results to simulations from ExoCAM (Exoplanet Community Atmosphere Model - derived from the CAM4 NCAR..., , **Changes after Nov 7, 2024:** Based on peer review comments, we have made minor updates to the figures. The .m script has been moved to Dryad from Zenodo, and the .mat file was updated.