Antarctica's Accelerating Collapse: Inside the Data That Has Scientists Alarmed

The Numbers

A comprehensive analysis of satellite altimetry data from the European Space Agency's CryoSat-2 and NASA's ICESat-2 missions shows that the West Antarctic Ice Sheet (WAIS) lost approximately 219 gigatons of ice per year between 2022 and 2025—triple the rate measured between 2012 and 2017.

The findings, published in Science by a team led by Dr. James Kirkwood at the British Antarctic Survey, indicate that ice loss has crossed what glaciologists call the marine ice sheet instability (MISI) threshold: the point at which warm ocean water penetrating beneath floating ice shelves triggers a self-reinforcing cycle of retreat.

What Is the Tipping Point?

The MISI hypothesis, first proposed in the 1970s, describes a feedback loop specific to ice sheets grounded below sea level—as the WAIS is across much of its base:

1. Warm water melts the underside of floating ice shelves
2. Ice shelves thin and lose their buttressing effect
3. Grounded ice flows faster into the ocean
4. As ice retreats into deeper bedrock basins, more ice is exposed to warm water
5. The cycle accelerates

"What we're seeing is consistent with the early stages of marine ice sheet instability. The geometry of the bedrock beneath West Antarctica means that once this process begins, it's very difficult to stop." — Dr. James Kirkwood, British Antarctic Survey

Regional Breakdown

The study identifies three glaciers as primary contributors to the accelerating loss:

Thwaites Glacier ("The Doomsday Glacier")

Thwaites alone accounts for roughly 4% of global sea level rise. The glacier's grounding line—where ice meets bedrock—has retreated 14 kilometers since 2017, exposing a deeper submarine basin that is accelerating melt.

Pine Island Glacier

Pine Island's ice shelf has fractured into multiple segments, reducing its ability to slow the flow of inland ice. Calving rates have increased 40% since 2020.

Smith Glacier

Previously considered relatively stable, Smith Glacier's ice loss has quadrupled in the study period, driven by a newly identified channel of warm Circumpolar Deep Water reaching its base.

Sea Level Implications

If the WAIS were to collapse entirely, global sea levels would rise by approximately 3.3 meters (10.8 feet). The study does not predict complete collapse but models a range of scenarios:

• Conservative estimate: 25–30 cm of sea level rise by 2100 from WAIS alone
• Mid-range estimate: 50–80 cm, assuming continued acceleration
• High-end estimate: 1.2+ meters if MISI feedback fully engages

Even the conservative estimate would dramatically increase flooding risk for coastal cities worldwide, affecting an estimated 800 million people.

The Response Gap

Despite the alarming data, policy responses remain largely focused on emissions reduction—which, while essential, cannot reverse ice loss already underway. Adaptation planning for sea level rise has been described by the study's authors as "woefully inadequate."

The study calls for immediate investment in coastal defense infrastructure, updated flood-risk mapping, and international coordination on managed retreat from the most vulnerable areas.

This article was collaboratively researched and written by 4 contributors using Kabooy's investigative deep-dive pipeline.