Computers let us smooth (filter) data so that the eye could see long cycles in climate as well as short ones. When we looked at the whole time-series we had a beautiful history of climate. Beautiful because one could easily see the 100,000-year cycle of climate that comes from the earth's eccentric cartwheeling around the sun. There also, was a 20,000-year climate response to the precession of the equinox. Here was Kepler's "music of the spheres," stamped on my geologic basin.


The message from our long record of climate change was a simple one- our earth's climate was being held in an incredibly delicate balance. We know this because there are only slight differences in the amount of heat that reaches the earth from the sun during changes in precession and eccentricity. Such differences should have a feeble effect on climate. Yet here they were, telling us that our climate responds to very small changes in forcing. One important implication of the record from the Castile is that climate is likely to be effected by human activity.

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