This is the author accepted manuscript.Data availability: The research data supporting this publication are openly available with CC BY 4.0 at https://doi.org/10.5281/zenodo.8178651We present results from 3D simulations of the Archean Earth including a prescribed
(non-interactive) spherical haze generated through a 1D photochemical model. Our sim ulations suggest that a thin haze layer, formed when CH4/CO2 = 0.1, leads to global
warming of ∼10.6K due to the change of water vapour and cloud feedback, compared
to the simulation without any haze. However, a thicker haze layer, formed when CH4/CO2
> 0.1, leads to global cooling of up to ∼65K as the scattering and absorption of short wave radiation from the haze reduces the radiation from reaching the planetary surface.
A thermal inversion is formed with a lower tropopause as the CH4/CO2 ratio increases.
The haze reaches an optical threshold thickness when CH4/CO2 ∼ 0.175 beyond which
the atmospheric structure and the global surface temperature do not vary much.Bell Burnell Graduate Scholarship FundUKRIScience and Technology Facilities Council (STFC)Leverhulme TrustNASAHill Family Scholarshi
