Climate trajectories in ﹩(T,f,{\mathrm{log}}_{10}\,p{{\rm{CO}}}_{2})﹩ phase space for a fourth feedback with c = −50 W m⁻² and various transition temperatures T_f (Earth-like S and V). Top: overlaid trajectories for T_f = 267, 269, 273, and 275 K (100 Myr integrations after 400 Myr transients). Bottom: individual attractors showing chaos at 267 and 275 K and limit cycles at 269–273 K. Small changes in the activation temperature near the freezing point, where the ice–albedo feedback acts most strongly, qualitatively alter the system dynamics, reflecting the strong sensitivity of the climate to feedback interactions in this regime.