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 3-activity sequence addresses the question: "To what extent should coastal communities build or rebuild?" The activity uses social science and geoscience data to prepare an evidence-based response to the question, in targeted US coastal communities.