  The effect caused by the presence of a number of distinct time scales in a
simple stochastic model for the Earth's atmosphere temperature fluctuations is
studied. The model is described by a dissipative dynamics consisting of a set
of coupled stochastic evolution equations. The system shows features that
resemble recent observations. In contrast to other approaches, like
autoregressive models, the fluctuations of the atmosphere's temperature depend
on parameters with clear physical meaning. A reduced version of the model is
constructed and its temporal autocovariance function is explicitly written.
