Constraining glacier elevation and mass changes in South America

Excluding the large ice sheets of Greenland and Antarctica, glaciers in South America are large contributors to sea-level rise¹. Their rates of mass loss, however, are poorly known. Here, using repeat bi-static synthetic aperture radar interferometry over the years 2000 to 2011/2015, we compute continent-wide, glacier-specific elevation and mass changes for 85% of the glacierized area of South America. Mass loss rate is calculated to be 19.43 ± 0.60 Gt a⁻¹ from elevation changes above ground, sea or lake level, with an additional 3.06 ± 1.24 Gt a⁻¹ from subaqueous ice mass loss not contributing to sea-level rise. The largest contributions come from the Patagonian icefields, where 83% mass loss occurs, largely from dynamic adjustments of large glaciers. These changes contribute 0.054 ± 0.002 mm a⁻¹ to sea-level rise. In comparison with previous studies², tropical and out-tropical glaciers — as well as those in Tierra del Fuego — show considerably less ice loss. These results provide basic information to calibrate and validate glacier-climate models and also for decision-makers in water resource management³.