Upper Greyling Lake Arctic Research (IMAGE) Northern Arizona University Caption At Upper Greyling Lake in Alaska, researchers combine the geomorphic evidence for glacier fluctuation with lake-core evidence to determine and interpret past climate change. Credit Northern Arizona University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.