1,2,4- 1Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden (michael.way@physics.uu.se)
- 2NASA Goddard Institute for Space Studies, New York, USA
- 3University of Colorado, Laboratory for Atmospheric and Space Physics, Boulder, Colorado, USA
- 4School of Ocean Sciences, Bangor University, Menai Bridge, UK
The Faint Young Sun Paradox posits that a modern Earth atmosphere placed on Earth in the Hadea/Archean would result in a snowball world. However, zircon data indicate that there was liquid water present at least 4.4 gigayears ago (Wilde et al. 2001). It is generally accepted that CO2 partial pressures (PP) were higher, but there are few consistent contraints on what that PP was. We use a full-complexity 3-D GCM (ROCKE-3D; Way et al. 2017) with ocean and sea ice dynamics to demonstrate that there are a wide variety of climate states possible in the Eoarchean. We see ice-free states with high CO2 PP, a variety of water belt states for medium CO2 PP, and snowball states with low CO2 PP. We also examine how the faster rotation rate of earth (shorter Length of Day) impact these climate states as well as what lower atmospheric pressures reveal given proxy data indicating pressures as low as 0.23 bar were possible in the Archean (Som et al. 2016). Studies like these not only have implications for characterizing ancient Earth's climate, but also contraining the climates of exoplanetary worlds, which we will touch upon.
Som et al. (2016) Nature Geoscience, 9, 448 http://dx.doi.org/10.1038/ngeo2713
Way et al. (2017) Astrophysical Journal Supplement Series 231:12 https://doi.org/10.3847/1538-4365/aa7a06
Wilde et al. (2001) Nature 409, 175 https://doi.org/10.1038/35051550
How to cite: Way, M., Wolf, E., and Green, M.: Exploring Earth's Eoarchean Climate in the context of the Faint Young Sun Paradox, Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-11, https://doi.org/10.5194/epsc2026-11, 2026.
