Global Temperature Maps (IMAGE) University of Arizona Caption These maps show global average surface temperature at different periods in Earth's history going back 24,000 years. The darker the shade of blue, the colder the temperature compared to today. Credit Matthew Osman Usage Restrictions This visual may only be used for the purpose of posting and/or reporting of this news release. Credit information 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.