Fig. 8. Level curves of the time of crisis function for (a) an irreversible lake (b = 0.4), and (b) an hysteretic lake (b = 0.8). (L_min = 0.1, L_max = 1, P_max = 0.5, and VL_max = 0.1). The times of crisis of two states that belong to the same solid line are finite and equal. Viab(K) (light gray area) and the set of states where the time of crisis is null merge. The time of crisis takes the infinite value for L smaller than L_min in both cases. In the case of the irreversible lake (a), the set of states with infinite cost (shaded area) is larger because there are states from which the property of interest cannot be restored before time T.