Antarctic calving loss rivals ice-shelf thinning

Area of Science:

• Glaciology and Climate Science
• Earth Observation and Remote Sensing

Background:

• Antarctic ice shelves regulate glacial ice flow into the ocean, influencing global sea-level rise.
• Limited data historically hindered large-scale monitoring of ice shelf dynamics and calving impacts.

Purpose of the Study:

• To generate a comprehensive, pan-Antarctic record of ice shelf coastlines and assess changes since 1997.
• To quantify the impact of ice shelf thinning and calving on buttressing and future sea-level rise.

Main Methods:

• Integration of multi-sensor optical and radar satellite data.
• Generation of spatially continuous, annual-resolution Antarctic coastlines from 1997 to 2021.
• Modeling the effects of coastline evolution on ice-shelf buttressing.

Main Results:

• A net loss of 36,701 ± 1,465 km² of Antarctic ice shelf area occurred between 1997 and 2021.
• Mass loss from ice-front retreat and ice shelf thinning were approximately equal, totaling nearly double the amount measurable by altimetry alone.
• Calving and thinning have equally reduced ice-shelf buttressing since 2007.

Conclusions:

• Antarctic ice shelf area is experiencing significant net loss, with future calving events posing risks.
• Combined mass loss from thinning and retreat nearly doubles estimates from altimetry alone.
• Continued ice shelf retreat will increasingly contribute to significant global sea-level rise.