Different climate states as a function of time and planetary distance a. The colors have the same meanings as in Figure 9. The four panels show differences in the CO₂-pressure dependence of land-based weathering. Panels (a)–(d) have β_L = 0.1, 0.25, 0.35, and 0.5, respectively. In all cases, W_L0 = W_S0 = 1/6. The values of other model parameters are the same as in Figure 9.