large construction site near Zurich shows just how abrupt. Workers here came across relatively fresh tree stumps, which, at first, they set aside without paying them any attention. A researcher found them, took samples, and investigated their age. The result: the stumps came from pines that were growing there almost fourteen thousand years ago. Even more amazing, though, were the fluctuations in temperature at that time. In less than thirty years, the temperature dropped as much as 42 degrees Fahrenheit, only to finally rise again by about the same amount.
