A very low order model of the general circulation of the atmosphere developed by Edward Lorenz consisting of three ordinary differential equations is analyzed as a nonlinear dynamical system. Lorenz's analysis of the model's response to fixed forcings and to the seasonal variation of the latitudinal temperature gradient parameter is repeated. Additionally, the response of the model to seasonal variations in the longitudinal temperature contrast parameter and lagged seasonal variations in the forcing parameters is considered. Various "climate change" scenarios for the model climate are investigated, including monotonic variation of the forcing parameters and spikes in the forcing parameters. These are compared with the model's seasonal variation to determine whether seasonal variability can serve as a proxy for climate change in the model.