Thousands of ice cliffs, one calmer answer about how fast ice sheets can fall

One of the most frightening ideas in climate science is that tall cliffs at the edge of ice sheets could collapse in a runaway chain reaction, driving sea levels sharply higher. A new study in Science replaces some of that fear with measurement: researchers surveyed thousands of ice cliffs across Earth's ice sheets with one consistent set of satellite observations — the first global check of its kind. The pattern they found is reassuring without being complacent: when cliffs do retreat rapidly, the retreat so far appears short-lived, with glaciers eventually restabilising. Lead author Jeremy Bassis of the University of Michigan is careful — nobody knows whether that holds as warming continues — but the dataset now lets scientists test their models against the real world instead of arguing from single glaciers. Better predictions are themselves a kind of good news: they tell coastal cities what to actually prepare for.

SDG 13 · Climate action