A group of Adelie penguins rides a sculpted iceberg in Adelie Land, East Antarctica. It is widely known that glaciers in West Antarctica and Greenland have been discharging ice into the oceans in response to warming in recent years, and that sea levels have risen as a result. By contrast, we hear little about the much larger East Antarctic ice sheet, which has been viewed as being less vulnerable to climate change owing to its location in an extremely cold climate. Chris Stokes and colleagues have used satellite imagery to map a large sample of glaciers along the Pacific coast of East Antarctica and show that in fact, they are responding to decadal climate variability. In concert with climate, glaciers retreated in the 1970s and 1980s, advanced in the 1990s, and approximately split between advance and retreat since the 2000s. The authors conclude that parts of the worlds largest ice sheet may be more responsive to external forcing than previously recognized.