This research seeks to 1) describe the vegetational history of central Alaska between 14,000 and 125,000 yr B.P.; 2) reconstruct past climate during this period based on palynological and geological data; and 3) compare these paleoclimatic reconstructions with a regional model of Alaska climate based on computer simulations of global climate. The vegatation history will be described from new palynological data coupled with results of previous paleoenvironmental studies. Response surface analyses and autoecological requirements of indicator species will be used to infer past climate from the pollen records. Global simulations, run with various combinations of boundary controls, will form the basis for modeling regional paleoclimates for Alaska. Data-model comparisons will be done to assess the correspondence between simulations and paleoclimatic records in Alaska. The results of this project will significantly expand the understanding of environmental change at high latitudes during the late Pleistocene and will provide a rare opportunity to examine data- model comparisons over a long period of time. Such an examination is essential for evaluating the ability to predict responses of climatic and terrestrial systems to future variations in boundary controls.