PETER D. MOORE
Division of Biosphere Sciences
The warming of the earth's climate following the last glaciation was interrupted in the North Atlantic region by a severe spell of cold conditions that lasted from about 10,800 to 10,000 years ago (called the "Younger Dryas" event). The cause of this setback to global warming is thought to be the diversion of ice meltwater from the North American ice sheet into the St. Lawrence River and, hence, into the North Atlantic. But the discovery of paleobotanical evidence for climatic cooling in the equivalent period in Alaska has now shown that the impact of this cooling was felt even in the Pacific area.
D.R. Engstrom, B.C.S. Hansen, H.E. Wright, Jr., "A possible Younger Dryas record in southeastern Alaska," Science, 250, 1383-5, 7 December 1990. (University of Minnesota, Minneapolis)
A relatively extensive literature exists concerning the impact of human trampling on...