Rapid glacier retreat rates observed in West Antarctica

The Pope, Smith and Kohler glaciers, in the Amundsen Sea Embayment of West Antarctica, have experienced enhanced ocean-induced ice-shelf melt, glacier acceleration, ice thinning and grounding-line retreat in the past 30 years. Here we present observations of the grounding-line retreat of these glaciers since 2014 using a constellation of interferometric radar satellites combined with precision surface elevation data. We find that the grounding lines develop spatially variable, kilometre-scale, tidally induced migration zones. After correction for tidal effects, we detect a sustained pattern of retreat coincident with high melt rates of ungrounded ice, marked by episodes of more rapid retreat. In 2017, Pope Glacier retreated 3.5 km in 3.6 months, or 11.7 km yr(-1). In 2016-2018, Smith West retreated at 2 km yr(-1) and Kohler at 1.3 km yr(-1). While the retreat slowed in 2018-2020, these retreat rates are faster than anticipated by numerical models on yearly timescales. We hypothesize that the rapid retreat is caused by unrepresented, vigorous ice-ocean interactions acting within newly formed cavities at the ice-ocean boundary. The Pope, Smith and Kohler glaciers in West Antarctica have exhibited faster than expected retreat rates in recent years, according to grounding-line observations from satellite radar interferometry.

Automated summary

Grounding-line observations from satellite radar interferometry show that the Pope, Smith, and Kohler glaciers in West Antarctica have experienced rapid retreat rates in recent years, faster than anticipated. The retreat is likely caused by unrepresented ice-ocean interactions within newly formed cavities at the ice-ocean boundary.