EOS, TRANSACTIONS AMERICAN GEOPHYSICAL UNION, VOL. 68, NO. 47, PAGE 1610, 1987
That Earth is constantly changing has been known since the beginnings of human reflections on the nature of our environments. The minute-by-minute changes in winds and clouds and the long-term trends in the climate of the continents, the rapid fluctuations in the humidity of the air and the sudden arrival of monsoons and tropical storms, the seasonal greening of grass and changing vegetation patterns around the globe, the rapidly spreading ripples in ponds and the slow meanderings of the Gulf Stream, the bursts of violent snow storms and the waxing and waning of the polar ice caps, all testify to the dynamic nature of the environments.