Various simple climate models of the Budyko and Sellers types are discussed. It is shown how the variation of the equilibrium position of the ice line as a function of available insulation is determined primarily by the range of latitudes over which heat transport is acting to smooth temperatures and the effectiveness with which this smoothing occurs. It is shown that when transports loosely associated with Hadley transports, atmospheric eddy transports and oceanic transports are separately modeled their net effect is to decrease the sensitivity of the climate substantially over what is obtained from existing simple models. It is also shown that the models we introduce in this paper are reasonably consistent with various aspects of the observed temperature and with various paleoclimatological features, while earlier simple models are not.