Redundancies in the Earth's climatological time series

We examine nonlinear coupling among a number of important climatological va riables, delta C-13, delta O-18 and insolation, using mutual information an d redundancy. The coupling among these variables is found to vary over diff erent climatological eras. The dependence between delta C-13 and delta O-18 is of particular strength in more recent samples. Tests for Granger causal ity suggest that delta O-18 has an effect on delta C-13 whereas the reverse is not the case. (C) 2000 Published by Elsevier Science B.V.