In this activity, students estimate the drop in sea level during glacial maxima, when ice and snow in high latitudes and altitudes resulted in lower sea levels. Students estimate the surface area of the world's oceans, use ice volume data to approximate how much sea levels dropped, and determine the sea-level rise that would occur if the remaining ice melted.

This activity in a case study format explores ice loss from the Greenland ice sheet by way of outlet glaciers that flow into the ocean. Students do basic calculations and learn about data trends, rates of change, uncertainty, and predictions.