Studies over the past decade have predicted substantial range shifts and increased extinction probabilities for thousands of plant and animal species under climate change. The preponderance of these studies rely on empirical niche modeling approaches (also called climate envelope models) and are almost entirely untested because they lack temporally independent data necessary for validating their projections. The impact of these studies on scientific, political, and public debate is high, as they often form the basis for conservation and resource management planning decisions. Consequently, assessing the accuracy of these projections is critical, yet is lacking. An important approach to assessing niche model projections is to calibrate models with historic data and compare model projections to present-day data. The use of historic data for validating niche model projections is vital because it provides the only means to directly measure projection accuracy under measured climate change and assess the factors and assumptions that influence model skill. Unfortunately, large-scale historic datasets suitable for use in niche model development are rare and our understanding of the accuracy of climate change projections on biota is limited. This organized oral session is designed to highlight the use of historic data for assessing predictions about biotic responses to climate change. Presentations will focus on a variety of topics ranging from practical evaluations of niche models under measured climate change, tests of ecological theory, uncertainty analysis, and the coordination and development of historic datasets for use in impact assessment research.