Fig. 3
From: Stable carbon isotope evolution of formaldehyde on early Mars
Evolution of δ13C (upper panel) in CO2 and H2CO, mixing ratios of CO2, CO, and H2 (middle panel), and surface temperature (lower panel) for 0.5-bar (dotted line) and 2-bar (solid line) atmosphere with a planetary albedo of 0.3, starting from 4 Ga.
