This document provides a brief overview of Dr. Thompson's talk on records of changes in climate in general and the most significant implications of the ice core records of past climate changes in particular. Because climate processes that have operated in the past continue to operate today, ice core records are providing very valuable insights. Within the last two decades, long cores of glacial ice have been used to establish and improve the record of past changes in climate. Analysis of ice cores from Antarctica, Greenland and tropical and subtropical areas have provided a wealth of detailed information on past climate changes. As the ice in these glaciers and ice sheets grew over time, layer by layer, tiny pockets of air were trapped within each layer, preserving a continuous record of the natural changes in the concentrations of greenhouse and other gases. In addition, these ice cores have preserved indirect/proxy records of changes in temperature (which can be closely estimated from the isotopic record of oxygen trapped in the ice), in the concentration of windblown dust, and in volcanic activity. By combining this information, these ice cores have preserved a 200,000-year history of climate changes and factors contributing to these …