Modeling the Ice-Age Climate

The last great (Wisconsin) ice age has long held the interest of climatologists, geologists, and geographers as the best documented of the several ice ages of the last million years. Although local glaciation maximums varied by several thousand years, the time 18,000 B.P. (years before present) is globally representative of this event. The changes of flora and fauna that accompanied this ice age are recorded in an extensive paleoclimatic literature, and are supplemented by widespread evidence of changes in the physical character of the earth's surface, such as changes in sea level, sea-ice extent, and local orography. From these and other evidence, estimates of the local nature of the ice-age climate itself have been derived at selected sites in terms of such variables as the local wind, temperature, or rainfall. Although they are insufficient to portray the overall global climatic regime, these estimates indicate that the ice-age climate was substantially different from today's in many regions of the world.