Do phenomenological dynamical paleoclimate models have physical similarity with nature?

Abstract. Phenomenological models may be impressive in reproducing empirical time series but this is not sufficient to claim physical similarity with nature until comparison of similarity parameters is performed. We illustrated such a process of diagnostics of physical similarity by comparing the phenomenological dynamical paleoclimate model of Leloup and Paillard (2022) with the more physically explicit Verbitsky et al (2018) model and established that, for the late Pleistocene, there is considerable physical similarity in terms of two crucial similarity parameters: (a) the ratio of the astronomical forcing amplitude to the terrestrial ice-sheet mass influx, and (b) the ratio of amplitudes of time-dependent positive and negative feedbacks.