The physical model is based on a global-mean radiative equilibrium model (0 dimension) (section 2.3). This radiative equilibrium model is coupled to an extremely simple representation of the other components of the climate system: ocean, carbon cycle, ice sheets (section 2.4). The model uses physical relationships, as well as empirical relationships whose parameters are adjusted to satisfy observational or theoretical constraints (section 2.1). The model is presently coded in TypeScript.