History in Ice (IMAGE) Columbia Climate School Caption Glaciers usually advance during cold times and recede during warm ones. These two in western Greenland are now retreating from where they may have been when the Vikings arrived. Credit Jason Briner Usage Restrictions Credit must be given. 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.