Volume loss from Antarctic ice shelves is accelerating

TLDR

Floating ice shelves around Antarctica restrain grounded ice‑sheet flow, and their thinning reduces this buttressing, increasing ice discharge to the ocean. We analyzed 18 years of continuous satellite radar‑altimeter data to compute decadal‑scale changes in ice‑shelf thickness across the continent. Ice‑shelf volume loss accelerated from negligible 25 ± 64 km³ yr⁻¹ (1994–2003) to rapid 310 ± 74 km³ yr⁻¹ (2003–2012), with West Antarctic losses up 70 % in the past decade, East Antarctic gains ceasing, and some shelves losing up to 18 % of thickness in under two decades.

Abstract

The floating ice shelves surrounding the Antarctic Ice Sheet restrain the grounded ice-sheet flow. Thinning of an ice shelf reduces this effect, leading to an increase in ice discharge to the ocean. Using 18 years of continuous satellite radar altimeter observations, we have computed decadal-scale changes in ice-shelf thickness around the Antarctic continent. Overall, average ice-shelf volume change accelerated from negligible loss at 25 ± 64 cubic kilometers per year for 1994–2003 to rapid loss of 310 ± 74 cubic kilometers per year for 2003–2012. West Antarctic losses increased by ~70% in the past decade, and earlier volume gain by East Antarctic ice shelves ceased. In the Amundsen and Bellingshausen regions, some ice shelves have lost up to 18% of their thickness in less than two decades.