How much Antarctic ice has been lost recently?

Three decades of satellite records reveal large grounding‑line retreat

A new circumpolar analysis of satellite observations finds that Antarctica’s ice sheet has retreated from its grounding lines substantially over the past 30 years. The study quantifies that loss as an area roughly ten times the size of Greater Los Angeles, and reports an average grounding‑line migration of about 442 square kilometres per year over the period examined.

Those numbers matter because grounding lines—the places where grounded ice meets floating ice shelves—help stabilize the continent’s largest glaciers. When grounding lines retreat, more ice can flow into the ocean and contribute to global sea‑level rise. The satellite map provides the first comprehensive, continent‑wide view of how grounding positions have shifted over decades, revealing regions that are losing contact with their beds and others that remain more stable.

Complementing the remote‑sensing picture, ice‑core and borehole work has started to open long archives of Antarctic climate. In a separate effort, scientists drilled more than 500 metres through Antarctic ice to extract a record extending back millions of years. That deep archive preserves past climate and ice‑sheet behavior over tens of millions of years and can help calibrate models that project future sea‑level responses.

What these lines of evidence together imply:

• Antarctic ice loss is measurable and accelerating in some sectors.
• Grounding‑line retreat raises the risk of increased ice discharge to the ocean.
• Deep geological and ice records are essential to constrain model projections.

It remains difficult to translate regional grounding‑line changes into precise global sea‑level numbers on short time scales, but the combined satellite and drilling results tighten constraints and point toward greater uncertainty and risk for coastal planning.