Watching the Ice: How Satellites and Scientists Are Tracking Glacier Change From Space

Our understanding of how the world's glaciers are changing rests on a remarkable infrastructure of observation — satellite constellations, airborne survey aircraft, GPS networks embedded in the ice, and dedicated field stations where scientists make painstaking manual measurements in conditions of extreme cold. Together, these systems provide a picture of glacier change that is unprecedented in its spatial coverage, temporal resolution, and scientific precision — and the picture they reveal is deeply concerning.

Satellite Altimetry — Measuring Ice from Space

NASA's ICESat-2 satellite, launched in 2018, fires 10,000 laser pulses per second at the Earth's surface and measures the return time with extraordinary precision — calculating ice surface elevation changes to centimetre accuracy across the entire globe. By comparing elevation measurements over time, scientists can detect precisely where and how fast glaciers are losing or gaining volume. ICESat-2's data has revealed previously unknown patterns of ice loss — including accelerating thinning at the margins of the Greenland Ice Sheet and structural weaknesses in Antarctic ice shelves.

GRACE — Weighing the Ice Sheets

The GRACE and GRACE Follow-On satellite missions (operated jointly by NASA and the German Aerospace Center) measure changes in Earth's gravitational field with extraordinary sensitivity. Because gravitational field strength depends on the mass distribution of material below, GRACE can detect the loss of ice mass from ice sheets and glaciers — essentially weighing the ice from space. GRACE data has been essential for quantifying the total mass loss from Greenland and Antarctica and for separating glacial contributions to sea level rise from other sources.