Maps Showing Ice Sheets Melting (1 of 2) (IMAGE) University of Sheffield Caption These maps show the rate at which the ice sheet over the British Isles during the last Ice Age melted. The ka on the images is short for thousand years and BP is ‘before present.’ So 27 Ka BP is the map of the ice sheet at 27,000 years ago. Credit University of Sheffield 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.