Jessica Tierney (IMAGE) University of Arizona Caption Jessica Tierney is a paleoclimatologist at the University of Arizona and a co-author of the new paper. Credit University of Arizona Usage Restrictions This visual may only be used in the context of reporting on the research referenced in this news release. Credit must be provided as indicated. License Original 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.