PREDICTIONS – 10 Years Later - Santa Fe Institute

8. A COSMIC HEARTBEAT
consumption data we see that it is still at the beginning of its growth; the
annual figures for the United States have been following an S-curve that
starts around 1850 and does not approach a ceiling until toward the end
of the twenty-first century (Appendix C, Figure 8.1).
Ten Years Later
The small circles in Appendix C Figure 8.1 show excellent
agreement between the forecast and the actual data since 1985.
It is worth pointing out that at the time of the forecast the trend
had been demonstrating a stubbornly flat pattern for more than
a decade. As it usually happens the deviation ended and the
natural trajectory was resumed.
The fact that energy consumption may stop growing by the middle
of the twenty-second century, stabilizing at a much higher level, has little
impact on us today. What does have a large impact is something that
is hardly noticeable in the picture described above: the small deviations
of the data points around the smooth trend. We can zoom in on these
deviations by looking at the ratio of each data point to the corresponding
level of the curve. Doing so, the overall trend fades from view,
highlighting the percentage of deviation from the established pattern of
overall growth. The resulting graph, Figure 8.1, presents a picture of
regular oscillations. It is so regular that a harmonic wave—a sinusoidal—with
a fifty-six-year time period can be made to pass very closely
to most points. It indicates that while Americans consume more and more
energy, sometimes they behave like gluttons toward this celestial food and
at other times they go on a diet. It also says that their gluttony is regularly
periodic.
This periodicity in energy consumption was first observed by Hugh
B. Stewart. 1 On several occasions before and after Stewart, economists
and others have pointed out many human activities that oscillate with a
period of fifty to sixty years. 2 It appears that it is not just Americans
consuming energy who behave this way; the whole world seems to
be pulsing to this rhythm. Drawing from a variety of data sources, I
present in the following figure striking examples that cover widely
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