Ice core methodology - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 124

Figure 3.13. Comparison of features at the site of interest with features in reference data.
Although there are differences between the morphologies of the site and the
reference, one can visually associate features of the two as shown by the dashed
vertical lines. But, a question arises as the data become noisier: How subjective is
this process and where does it pass from reasonable logic to the eye of the
beholder?
Wunsch (1999) emphasized that ''the purely random behavior of a rigorously
stationary process often appears visually interesting, particularly over brief time
intervals, and creates the temptation to interpret it as arising from specific and
exciting deterministic causes.'' He went on to say:
''One often sees discussions of apparent visual correlations between two or
more climate time series. One must be extremely careful not to be misled by
oscillations that are merely the happenstance of random variability and imply no
causal connection at all. The human eye developed to find patterns in nature; it
sometimes sees patterns where none exist. Red noise (strongly auto correlated)
processes are particularly prone to generating oscillations that to the eye look
related.''
In his conclusion, Wunsch (1999) said:
''Undoubtedly the real climate record contains physically significant trends
and changes in spectral shape or energy levels. Two visually but statistically