Glaciers and ice sheets shape Earth’s landscape, provide water and nutrients for plants, animals, and people, and significantly contribute to flooding and sea level rise. 

A key way that scientists track the changing size of glaciers and ice sheets is to calculate their mass balance—their net gain or loss over the course of a year. They gain mass through the accumulation of new snow and other precipitation that freezes into ice; they lose mass through melting and by calving icebergs into the ocean. Measuring the mass balance of glaciers and ice sheets provides important details for understanding trends in how much they are growing or melting; for estimating the amount of freshwater they can provide now and in the future; and for calculating the role of ice in global sea level rise.

NASA’s holdings include datasets collected by laser altimeters and other precision instruments researchers can use to make glacier and ice sheet mass balance calculations.